gas reference package quickreferenceguide2010v2.pdf · gb-gas.co.uk gas reference package 2010v2...

gb-gas.co.uk GAS REFERENCE PACKAGE 2010v2 Aim To Pass With Gb-Gas

1

GAS REFERENCE

PACKAGE

This document is free to download and copy from www.gb-gas.co.uk


2

Combustion See www.gb-gas.co.uk for more details.

Visual inspection

The main reasons for incomplete combustion

1. Lack of oxygen (soft yellow flames)

2. Incorrect burner pressure (over gassed / under gassed)

3. Flame impingement (flame chilling)

A good pre-aerated flame should be bright blue with a strong inner and outer cone,

and above all will have a roar. If there is any yellow in the flame then it is incorrect.

(Do not mistake yellow for orange, as orange flames are usually dust being burnt.)

Procedure for carrying out a service with the aid of a Combustion Analyser.

1. Carry out the service as per manufacturer’s instructions

Tightness test, clean and inspect.

2. If the appliance is range rated turn to maximum setting

Traditional boilers adjust to max burner pressure.

Combination boiler on hot water mode or chimney sweep mode.

Condensing boilers check manufacturer’s instructions.

All other appliances burner(s) on full.**

**Be aware that checking a eye level grill when the hob burners are on will cause

incomplete combustion on the grill.

3. Take flue gas analysis

If acceptable:

Reset to original burner pressure / gas rate and retest if ok

Then conduct:

Flue and spillage test

Check safety controls.

Ventilation.

Confirm safe operation

If unacceptable:

If possible rectify fault(s) then re test

If not possible follow the unsafe situations guidelines.

At Risk for flued appliances

Immediately Dangerous for Flueless appliances.

4. Complete job documentation

If using a flue gas analyser acceptable readings vary depending on the

appliance type. Consult manufacturers’ instructions. If the manufacturer

supplies a Co2 reading only then make sure you are very close to that

reading.

http://www.gb-gas.co.uk/


3

BS 7967-3

APPLIANCE TYPE CO/CO2 RATIO

Back boiler unit Boiler 0.008

In combination with fire 0.020

Central heating boiler 0.008

Hot water circulator 0.010

Flued space heater 0.020 (check man instructions)

Flueless space heater 0.001

Water heater flued and Flueless 0.020

Warm air heater 0.008

Flueless cooker Oven 0.008

Hob Visual inspection of flames

Grill (CE marked) 0.010

Grill (No CE mark) 0.020

Range oven flued 0.020

Refrigerator (LPG) 0.007

Tumble drier Flued 0.010

flueless 0.001

Gas lights (LPG) 0.020

Any ratios above these readings maybe through, misuse, lack of maintenance, damage

or aging.

Make sure the probe is placed

correctly:

Open flued: centre of the flue, or

200mm inside the draught diverter.

Room sealed: From the

manufacturers test point or 200mm

inside the flue duct from outside

Flueless appliances: On the flue

outlet using the spreader bar tester.

The appliance has run for 5 mins.

Monitor the Co reading carefully if

this starts rising quickly then

remove the tester as you may

damage the equipment.

If you don’t get the reading you are

looking for let it run for a further 10

mins and retest.

A full clean and check or repair of

the appliance is essential and then

re-tested.

If it is not possible to achieve these

levels then the appliance should be

regarded as at risk for flued

appliances and immediately

dangerous for Flueless appliances.

COMBUSTI

ON

ANALYSER Natural gas

Co…. 21

O2… 4.8 Co2...8.9

C

O

M

B

US

TI

O

N

A

N

A

L

YS

IS


4

Carrying out a room test for carbon monoxide with a Combustion Analyser.

General

1. Position an open ended sampling probe approximately 2 m above floor level in

the centre of the room and at least 1 m away from any suspect appliance

installation.

2. Close all external doors, windows and customer adjustable ventilation.

3. Record the level of CO over a 15 min period. If the indoor level of CO starts

to rise during this period, check for CO migration from other sources.

4. If there is no rise then proceed to test the appliance.

Room

sealed and

open flued

appliances

Operate the appliance at full rate until the CO reading stabilizes or begins to fall,

whichever occurs first.

Cookers

Ensure that all permanent ventilation to the space in which the appliance is situated is

unobstructed.

Place a saucepan on each of the pan-supports above the two largest hotplate burners

and put approximately a litre of water in each and cover with a lid. Use a saucepan

with a flat base and a base diameter of between 160 mm and 220 mm.

Place the grill pan in its highest position under the grill.

Open/operate the customer adjustable ventilation in accordance with the cooker

manufacturer’s instructions, e.g. window or extractor fan.

Light the grill, oven and the two hotplate burners at their maximum setting. Turn the

oven down to gas mark 5 (or mid-range if not calibrated in gas mark numbers).

Record the CO levels at 1 min intervals.

Turn the hotplate burners down to simmer when the water boils. Turn the grill off

after 30 min.

If during the test the CO reading:

begins to fall without exceeding 30 ppm, stop the test; the installation and cooker are

satisfactory;

does not exceed 30 ppm for longer than 20 min and begins to fall and does not exceed

90 ppm at any time, stop the test; the installation and cooker are satisfactory;

Exceeds 90 ppm at any time, stop the test, ventilate the room, identify the cause,

rectify and repeat the test.

Flueless

water

heaters


unobstructed.

Close all customer adjustable ventilation to the space in which the appliance is

situated.

Light the appliance and operate it at maximum gas rate for 5 min recording the CO

levels at 1 min intervals.

Flueless

space

heaters


unobstructed.

Close all customer adjustable ventilation to the space in which the appliance is

situated.

Light the appliance and operate it at maximum gas rate for 30 min recording the CO

levels at 1 min intervals.


5

Pipe work inspection See www.gb-gas.co.uk for more details.

Common faults found on the meter installation:

Valve handle

missing

Valve handle drops

to on position

On / off label

missing

Incorrect materials

at meter

Incorrect or no

telephone number

No emergency

procedures label

No governor on

primary meter

Governor not

sealed

Common faults found on pipework installation:

No 10mm² bonding

within 600mm of

the meter

To close to electric

meters or outlets

(150mm)

To close to electric

cables or conduits

(25mm)

Pipework

inappropriately

supported

Incorrect sleaving

methods

Incorrect materials

used in pipework

Incorrect fittings

used in pipework

Unsatisfactory

workmanship

Re-establishing gas supplies

This checklist should be conducted every time the gas has been turned off. Even if only conducting a

tightness test.

A visual check on the pipework installation

A visual check of the appliances should be made

Calculate the ventilation requirements for the installation

Test for soundness

Purge the meter from the furthest practical point Purge volume = 5x the meter badge capacity for installations with pipe up to 28mm

e.g. ( imperial meter(ft³) = 5x 0.071ft³ = 0.355ft³) (metric meter(M³) = 5x 0.002m³ = 0.010m³)

If there is pipework greater than 28mm or a meter bigger than a 6m capacity a calculation must be used U16 meter 5 x 0. 006m³ = 0.030m³ Purge volume = pipework length x volume of 1m length x 1.1 (for fittings) x 1.5 plus meter purge volume.

Eg 3 m of 35mm pipe plus a U16 meter... 3 x 0.00084 x 1.1x1.5 =0.004158 m³ + 0.030 m³ =0.034158 m³.

See page 26 or IGEUP1B FOR MORE DETAIL or visit gb-gas.co.uk

MMaatteerriiaall aanndd nnoommiinnaall ssiizzee ooff ppiippee VVoolluummee ooff 11mm lleennggtthh ooff ppiippee

SStteeeell // ssttaaiinnlleessss sstteeeell CCooppppeerr

1155mmmm ½½ 00..0000002244 ((mm³³)) 1155mmmm 00..0000001144 ((mm³³))

2200mmmm ¾¾ 00..0000004466 ((mm³³)) 2222mmmm 00..0000003322 ((mm³³))

2255mmmm 11 00..0000006644 ((mm³³)) 2288mmmm 00..0000005544 ((mm³³))

3322mmmm 11¼¼ 00..00001111 ((mm³³)) 3355mmmm 00..0000008844 ((mm³³))

Purge the remaining sections of the installation (light and detect method)

Re-light each appliance in turn checking that all user controls are

working satisfactorily

Check all open flued appliances for spillage

Inform customer on appliance use and gas safety



6

Testing for tightness (Using Gas) NEW SYSTEMS See www.gb-gas.co.uk for more details.

After visually inspecting the installation

1. Turn the gas off

2. Make sure all appliances are disconnected

3. Turn all valves on pipework on.

Connect a zeroed manometer to the meter test point and start the test procedure

Test name

Reason

Test pressure Test time

Let-by test To check if MCV is passing,

if greater than (max 0.25mb

or 0.2mb with a digital) report to supplier. To confirm

let-by spray LDF in valve

10mb 1 min

Stabilisation to allow for temp. differences

20mb 1 min

Soundness test (No pressure drop or smell

allowed) 20mb 2 min

4. Make sure all appliances are re-connected

5. Turn all valves on including lifting the cooker lid.


Test name

Reason


Stabilisation To allow for temp.

differences

20mb 1 min

Soundness test (record any drops here)

20mb 2 min

Gas test for pipework and appliances in new installations

NO DISCERNABLE DROP ALLOWED –(max 0.25mb or 0.2mb with a digital)

The test pressure must never be greater than 23mb as the governor may lock up,

if so you will have to spray all the inlet pipework to check for leaks.

Air testing Connect a zeroed manometer to the TEST TEE and start the test procedure.

Test name Reason Test pressure Test time

Stabilisation to allow for temp. differences 20mb 1 min

Soundness test (record any drops here) 20mb 2 min

Air test would be used for pipework in new installations

NO DISCERNABLE DROP ALLOWED -(max 0.25mb or 0.2mb with a digital)

******** Test all testpoints with leak detector fluid*********



7

Testing for tightness (Using Gas) Existing Systems


1. Turn the gas off

2. Make sure all appliances are connected



Test name

Reason


Let-by test To check if MCV is passing,

if greater than (max 0.25mb

or 0.2mb with a digital) report to supplier. To confirm

let-by spray LDF in valve

10mb 1 min

Stabilisation To allow for temp.

differences

20mb 1 min

Soundness test (see information below) 20mb 2 min

If there is no discernable pressure drop in the system and no smell

of gas then the system has passed.

If there is a drop in the system then all the appliances must be

isolated and the pipework tested on its own (no discernable drop is

allowed in the pipework)

If the drop is at an appliance and within the limits set (below) and

no gas can be smelled, then the system may be passed.

The test pressure must never be greater than 23mb as the

governor may lock up, if so you will have to spray all the inlet

pipework to check for leaks.

Maximum drop allowed

U6 meter 4mb over 2min* or

2.5 mb if there is

pipe work greater

than 28mm

E6 meter 8mb over 2min*

4.5 mb if there is

pipe work greater

than 28mm

U16 meter 1mb over 2 min* even if the pipe is greater than 28 mm

* in any situation if the recorded drop is in the pipework it is an immediate fail

* if there is a sell of gas the installation is an immediate fail



8

Testing for tightness (Using Gas) Maximum Operating

Pressure (MOP) greater than 75 MB


1. Turn the gas off

2. Make sure all appliances are connected and no pilot lights



Test name

How Reason

Test

pressure

Test time

Let-by test

for Meter

Control

Valve (A)

Take the system up to standing

pressure.

Close meter control valve.

Release pressure e.g. (by

opening a cooker)

Hold open regulator valve and

observe.

To check if MCV is

passing, if greater than

(max 0.25mb) report to

supplier. To confirm

let-by spray LDF in

valve

Approx.

2-10mb

1 min

Let-by test

for

Regulator

lock out (B)

Release the regulator valve

pressure should increase

slightly.

Open meter control valve and

observe.

to check if regulator is

passing on lock out, if

greater than (max

0.25mb) report to

supplier

Approx.

2-10mb

1 min

Stabilisation Raise pressure to 19 mb close

meter control valve

To allow for temp.

differences

19mb 1 min

Soundness

test

Observe (No discernable

pressure drop or smell

allowed)

19mb 2 min

No discernable drop is any drop greater than 0.25mb

The test pressure must never be greater than 19mb as the governor

may lock up,

Because the inlet pipework is subjected to pressures up to 2 bar you

must spray all the inlet pipework to check for leaks.

Maximum drop allowed

U6 meter 4mb over 2min* or

2.5 mb if there is

pipe work greater

than 28mm

E6 meter 8mb over 2min*

4.5 mb if there is

pipe work greater

than 28mm

U16 meter 1mb over 2 min* even if the pipe is greater than 28 mm

* in any situation if the recorded drop is in the pipework it is an immediate fail

* if there is a sell of gas the installation is an immediate fail



9

Ventilation “When checking ventilation requirements always observe manufacturers instructions”

Calculate MAX NET heat input Take MAX GROSS heat input from the

appliance DATA BADGE and by 1.1

OPEN FLUED Advent Top Bottom Outside

ONE Open flued appliance in a room

MAX net heat input

YES

*

*

-7kW

X 5cm²

ONE Open flued appliance in a

compartment vented to outside

MAX net heat input

*

X 5cm²

X 10cm²

*

ONE Open flued appliance in a

compartment vented to a room

MAX net heat input

*

X 10cm²

X 20cm²

-7 kW

X 5cm²

TWO Open flued appliance in a room

MAX net heat input

ADD two heat inputs together and

calculate as above

TWO Open flued appliance in a

compartment MAX net heat input


calculate as above

TWO Open flued GAS FIRES in the

same room (less than 14kW) additional ventilation may not be

required

TWO Open flued GAS FIRES in the

same room (greater than 14kW)

Add heat inputs together and calculate as

for one open flued appliance in a room

IF flue or spillage test fails additional ventilation is required

ROOM SEALED Top Bottom Outside

ONE Room Sealed appliance in a room

MAX net heat input

*

*

*

ONE Room Sealed appliance in a

compartment vented to outside

MAX net heat input

X 5cm²

X 5cm²

*

ONE Room Sealed appliance in a

compartment vented to a room

MAX net heat input

X 10cm²

X 10cm²

*

FLUELESS APPLIANCES OPENABLE

WINDOW OR

SIMILAR

ROOM SIZE (M³)

<5 5-10 10-15 15-20 >20

COOKER YES 100 CM² 50 CM² * 0 CM² 0 CM² 0 CM²

WATER HEATER YES NOT 100 CM² 50 CM² 50 CM² 0 CM²

TUMBLE DRIER YES 100 CM² 100 CM² 0 CM² 0 CM² 0 CM²

* IF THE ROOM CONTAINS A DOOR TO OUTSIDE THEN A VENT IS NOT REQUIRED

MULTI- APPLIANCE SITUATIONS

SIMILAR flued appliances in a room

MAX net heat input


calculate as above

DISSIMILAR flued appliances in a room TAKE largest ventilation requirement

Measuring ventilators Calculate the free air area (measure the holes) the hole

MUST be from 5 to 10 mm and not closeable.

if answer is in MM² 100 to get CM²


10

Pressure testing

Meter Standing and Working Pressure

1. Connect a zeroed manometer to the meter test nipple.**

2. Turn on gas slowly and record STANDING PRESSURE (APPROX. 25mb)

3. Then turn on ONE appliance: Cooker 3 hotplates.

Fire on full rate.

Boiler on full rate.*

Other appliance full rate.

*a range rated boiler may cause a problem, if using a combi. Use hot water mode

4. Record reading on the WORKING PRESSURE (must be from 19mb to 23mb) if

to high or to low contact gas supplier for primary meter, if it is a secondary meter

adjust (screw down clockwise to increase pressure.)

**To read the manometer correctly add both legs together and divide by 2**

If the meter is running at full rate (6m³/hr), with an inlet pressure of 19mb at the

governor. The drop or (absorption) through the meter will be as much as 4mb.

Inlet working pressure

This test is prove the pipework is suitable in size and length with no blockages.

1. Connect a zeroed manometer to the boiler inlet test point.

2. Turn on the appliance and record the reading( only 1mb drop allowed through

the pipeline) see page 27 for more details

e.g. working pressure at the meter : 21mb

inlet working pressure : 20mb

installation acceptable.


Burner pressure

This test is to prove that the appliance is burning within the limitations set by the

manufacturer.

1. Connect a zeroed manometer to the boiler BURNER PRESSURE test point.

2. Turn on the appliance and record the reading (compare the reading against the

appliance data badge. The reading must be within the range)



BURNER

STANDING PRESSURE at the meter (APPROX. 25mb)

Test method (see below)

WORKING PRESSURE (must be 21± 2 mb) AT THE METER

Test method (see below)

APPLIANCE INLET

WORKING PRESSURE

(max 1mb drop form working

pressure at the meter)

APPLIANCE BURNER

PRESSURE (check against

appliance data badge)

Multifunction control


11

Heat Inputs And Gas Rates. See www.gb-gas.co.uk for more details.

The purpose of these tests is to prove how much gas is being burnt by the appliance

IMPERIAL METER (ft³): E.G. U6

1. Make sure only the appliance to be tested is on (turn up full)

2. Got to the gas meter and time one complete revolution of the red dial on the meter.

3. Convert the time into seconds and apply into the calculation.

U6 GAS RATE = 100.8 TIME IN SEC FOR 1FT³ OF GAS

=_______________M³/HR

U6 (gross) HEAT INPUT= 1064 TIME IN SEC FOR 1FT³ OF GAS

=_______________kW

U6 (net) HEAT INPUT = 967 TIME IN SEC FOR 1FT³ OF GAS

=_______________kW 4. Compare the reading against the appliance data badge. The reading must be within

the range.

METRIC METER (M³): E.G. E6, G4

1. Make sure only the appliance to be tested is on (turn up full)

2. Go to the gas meter and record the reading and at the same time start the stop

watch.

3. Two minutes later (on the stop watch) record the second reading.

4. Subtract the first reading from the second reading and apply into the calculation.

EXAMPLE

Reading after two minutes 1 0 0 7 1 3 3 M³

First reading on meter - 1 0 0 7 0 7 2 M³

Amount of gas used = 0 0 0 0 0 6 1 M³

E6 GAS RATE = TWO MINUTES OF GAS X 30

=_______________M³/HR

E6 (gross) HEAT INPUT = TWO MINUTES OF GAS X 317

=_______________Kw

E6 (net) HEAT INPUT = TWO MINUTES OF GAS X 288

=_______________Kw Compare the reading against the appliance data badge. The reading must be within the

range.

1 revolution = 1ft³ of gas



12

Gas safety devices and Controls See www.gb-gas.co.uk for more details.

Flame supervision devices or F.S.D s Purpose : To avoid unlit gas entering the appliance

1 Thermoelectric FSD Recognise because it has a push button and

thermocouple

Found in every type of gas appliance

Test 1. Light pilot and establish.

2. Turn gas off time until click

2 Bi-metallic strip FSD Recognise Loop of metal

Found Only found on hot water circulators

Test 1. Light pilot and establish.

2. Turn pilot off time until burner

turns off

3 Vapor pressure FSD Recognise Small probe directly on oven

burner, burner lights on low flame

Found Only found in cookers

Test 1. Light burner (should light on

low flame) after approx. 30sec

rising to high flame.

2. Turn gas tap off, wait for 90 sec

and re-light (should light on

low flame)

4 Flame rectification

FSD

Recognise Ignition starts automatically to light

the pilot or main burner

(electronic ignition) Found On all appliances

Test 1. turn appliance on make sure

flame lights and establishes

2. Keep the demand on the

appliance and turn the gas off.

The appliance should go into

lockout or keep sparking

FSD shutdown times

* BOILERS 60 SEC

* W / AIR HEATERS 60 SEC

* COOKERS 90 SEC oven

60 SEC other

* WATER HEATERS 90 SEC

* D.F.E. GAS FIRES 120 SEC

* OTHER GAS FIRES 180 SEC

* *Manufacturers instructions may differ from the times stated above. *



13

Thermostats Purpose: to control heat

4 Mechanical

thermostat

Recognise Dial with numbers indicated

(Vapor expansion) Found Mostly on cooker ovens

Test 1. Turn oven on and heat up for 15

min.

2. Turn control to lowest setting

flame should drop to by-pass

rate

Mechanical

thermostat

Recognise Dial with numbers indicated

(rod type) Found Old cookers and water heaters.

Test Heat up appliance gas should turn

down / or off (depending on

appliance)

5 Electric thermostat Recognise Dial with numbers indicated

Found Boilers etc

Test Heat up appliance thermostat

should turn the solenoid off

6 Solenoid Purpose An electrically operated gas valve

Found Boilers etc

Test 1. Turn electricity on valve opens

2. Turn electricity off valve closes

7 Multi-function

control

Purpose A collection of controls in one unit

Found Boilers etc

Test If the FSD, Regulator and solenoid

work then the multi-function

control is working.

8 Relay valve Purpose An automatic gas valve

Found Old boiler, commercial cookers

Test 1. Weep gas of the top of the unit

and the burner should open.

2. Stop the weep and the burner

will go off.

9 Lid safety device Purpose To turn off the burners, when the

lid drops

Mechanical safety Found Cookers, (hotplates)

cut off Test 1. Turn on gas tap to hotplate.

2. Lower lid and gas should turn

off


14

10 Gas tap Purpose To control the flow off gas safely

Found Cooker, fires ,etc

Test 1. tap locks in the off position

2. tap functions correctly

11 Atmospheric

Sensing

Device

(ASD) (VSD)

Purpose To close down the open flued

appliance automatically, if the

appliance and flue operate

incorrectly

Found All open flued appliances after 1998

Test 1. light pilot.

2. Close air inlet hole and observe

flame (turn yellow)

12 Atmospheric

Sensing

Device / over heat

Purpose To close down the open flued

appliance automatically, if the

appliance and flue operate incorrectly

Thermocouple

interrupter

Found On water heaters, Flued water heaters

this is usually a overheat safety

device. Flueless used as an ASD

Test Visual inspection to check wiring to thermocouple (no

links) and check FSD

13 Regulator Purpose Adjuster screw to alter burner

pressure

Found Boilers etc

Test 1. Attach manometer to test point

2. Adjust screw to alter pressure

14 Zero governor Purpose To compensate for the negative

pressure caused by the fan, on the

gas valve (this could pull more gas

into the burner than intended)

Found New fan flued room sealed

appliances

Test 1. Attach manometer to burner pressure test point

Turn appliance on when the fan comes on the

manometer reads negative pressure, quickly going to

positive pressure when the burner comes on.

15 Medium to low

pressure Regulator

Purpose To lower incoming gas pressure from

2 bar to 21mb

Found Above the meter control valve, fitted

with a reset handle

Test 1. make sure working pressure is 21mb

make sure the regulator lockout does not let-by


15

Flame rectification / conductance

Sequence of events for an electronic ignition fan flued boiler

yes no

1 Demand on the system turns pump then fan on.

2 Fan turns on fan pressure switch

3 Pressure switch turns on ignition system.

Proving AC to AC through electrodes

4 Ignition system turns on power to the solenoid via the

control stat and high limit stat.

5 Ignition spark ignites the gas

6 Ignition system proves the flame by rectification of the

current through the ionized layer of the flame AC to DC

7 Ignition system monitors flame by DC current

To test the flame rectification system

1 Put a demand on the system and make sure it fires up and

stays lit

2 Turn the gas off system should start sparking again then go

into lockout or keep sparking


16

Cooker Controls See www.gb-gas.co.uk for more details.

FSD

Vapour pressure

Test procedure Light the oven burner, it should light on the low flame

After approx. 30 seconds it should rise to the high flame

Turn oven gas tap off

After 90 seconds re-light the oven burner, it should light on low flame

If it lights on the high flame then the FSD is faulty

OR Thermoelectric Test procedure

Push the control handle in and turn to a setting.

Light the burner hold in the control handle for 30

seconds

Release the control handle the flame should stay on the

burner.

If the flame goes out the thermocouple or

thermoelectric valve is faulty

Turn the gas off, at the meter or appliance isolation

valve, after the flame goes out at the burner time until a

click is heard or the time limit is reached.

Turn the gas back on without pushing in the control

knob in ,the gas should not come back through the burner

If the gas comes back on thermoelectric valve is faulty

Oven thermostat

Test Procedure

Light the oven burner and turn to high setting

Shut the door and leave for 15 min

Open the door to see the flames and turn to the lowest

possible setting

The flame should drop to the bypass rate

If flame goes out (faulty bypass)

If flame does not drop (faulty thermostat)



17

Unsafe situations

To find out if a situation is NCS AR or ID consult the unsafe situations document

Category Action taken

Label used Notice used

N.C.S. NOT TO

CURRENT

STANDARDS

Inform responsible person, and repair fault if

possible. Fill in (notice) and give copy to

responsible person

None Fill in the NCS

section of

warning notice

form

A.R.

AT RISK


possible. If not turn appliance off attach

(label) and fill in (notice) and give copy to

responsible person.

Warning label do

not use

Fill in the A.R.

section of

warning notice

form

I.D. IMEDIATELY

DANGEROUSE


possible. If not DISCONNECT appliance

and attach (label) and fill in (notice) and

give copy to responsible person.

Warning label do

not use

Fill in the I.D.

section of

warning notice

form

Flue inspection

When visually inspecting a flue start at one end and work methodically to the other

end making a note of all the problem areas

Common faults to look for are

Open flues Catchment area too

small

Catchment area not

sealed

Catchment area has

letterbox opening

Incorrect flue for

appliance

Flue not sealed to the

appliance

Flue damaged Flue upside down Signs of spillage

Joints leaking Joints not sealed Flues not clipped Minimum of 600mm

between draught

diverter and first bend

Bend no greater than

45

Flue too small for

appliance.

To close to

combustible material.

Incorrect terminal

Terminal not high

enough through the

roof.

Copex liner not fixed

at the top or bottom

Copex not sealed to

appliance

Incorrect material or

methods used.

Room sealed flues Flue not sealed Appliance seals

damaged or missing

Terminating in wrong

position.

No terminal guard

Flue length to long Flue damaged Incorrect material or

methods used

Appliance or flue

leaking.


18

FLUE TESTING See www.gb-gas.co.uk for more details.

The purpose of a flue test is to prove a few points about the flue:

1. Flue draws all the products of combustion up the flue.

2. The flue does not leak from any joints or connections.

3. The flue terminates in the correct position.

4. The flue does not leak through any other flue system.

Before carrying out the test a few points MUST be covered.

1. Explain to the customer what you are about to do (in case they panic)

2. Close doors and windows (put the flue under its worst conditions)

3. When testing a flue with a fan in the area (it may not be necessary to turn the fan

on as the problems that may occur with back pressure are checked when

conducting a spillage test)

Test the flue

from cold

IMPORTANT

while completing the test;

All smoke must be drawn into the flue.

The smoke must terminate at the correct point.

The flue must not leak into any other flue, room or dwelling

↓

Pre-test with

a smoke

match

→

FAIL

Heat the flue

for 10 min and

retest

↓ ↗ ↓

Test with a

smoke pellet

Pre-test with a

smoke match →

FAIL

Heat the flue

for further 10

min and retest

If the flue is

condemned it may

require repair or

cleaning further

investigation is

required. Follow

the unsafe

situations

procedures

↓ ↓ ↗ ↓

OK Test with a

smoke pellet

Pre-test with a

smoke match →

FAIL

Heat the flue

for further 10

min and retest

↓ ↓ ↗ ↓

OK Test with a

smoke pellet

Pre-test with a

smoke match →

FAIL

CONDEMN

↓ ↓ ↗

If heating the flue with a blow torch, it

may require as much as 30 min to heat

properly

OK

Test with a

smoke pellet

↓

OK



19

SPILLAGE TESTING See www.gb-gas.co.uk for more details.

The purpose of a spillage test is to prove a few points about the appliance:

1. The appliance draws all the products of combustion into the flue.

2. The appliance and flue design are working correctly.

3. The appliance has no fumes entering the room

4. The appliance is safe to use

Before carrying out the test a few points MUST be covered.

1. Explain to the customer what you are about to do (in case they panic)

2. Close doors and windows (put the flue under its worst conditions)

3. Turn the extractor fans on in the room and test

4. Turn extractor fans on in any other room in the house and leave the door

between the rooms open. And re test

5. When testing a flue with a fan in the area test with the fan on and with the fan off.

Heat the

appliance for 5

minutes

IMPORTANT

while completing the test;

All smoke must be drawn

into the appliance.

The appliance must be left

on at maximum setting.

↓

Leave the

appliance on and

place smoke

match in the

desired area

→ FAIL

Heat the

appliance for

further 10 min

↓ ↗ ↓

Is all the

smoke drawn

into the

appliance

Leave the

appliance on and

place smoke

match in the

desired area

→ FAIL

CONDEMN

↓ ↓ ↗

OK Is all the

smoke drawn

into the

appliance

If the appliance fails then further investigation may be required

The appliance may be;

1. Over gassed.

2. Sooted up.

3. Blocked flue or flue ways.

4. Bad flue design.

5. Faulty appliance.

↓ OK


gb-gas.co.uk GAS REFERENCE PACKAGE 2008.1 Aim To Pass With Gb-Gas

20

Spillage Testing for room sealed appliances See www.gb-gas.co.uk for more details.

• This to make sure the appliance is sealed form the room.

• Remove the outer case if its not part of the seal.

• Visually inspect for any corrosion, distortion and problems with

seals

• While the appliance is turned on

• Move a lighter or match around

1. All the case seals,

2. Viewing windows,

3. All Pipes and wires entering the

pressurised case

4. Around the flue seals

• If the lighter flame is distorted

or blows out then this is a fail.

D Below a gutter, or

sanitary pipe work

300 [#] 75 [@]

E Below the eaves 300 [#] 200

F Below a balcony or

carport roof

600 200

G Above ground, roof or

balcony level

300 300

H From vertical drain/soil

pipe work

75 [@] 75 [@]

J From an internal or

external corner

600 300

K From a surface or

boundary facing the

terminal

600 600 [+]

L Vertically from terminal

on same wall

1500 1500

M Horizontally from

terminal on same wall

300 300

N From a terminal facing

the terminal

600 1200

P From an opening in a

carport (e.g. door,

window) into the building

1200 1200

R From a vertical

structure on the roof

[Note $]

n/app n/app

S Above an intersection

with the roof

n/app n/app

Notes: @. a terminal serving a natural draught and fanned draught appliance

more than 5kW heat input should be at least 300mm and 150mm

respectively from combustible material.

#. Where a natural draught flue terminates not more than 1m below a

plastic projection or not more than 500mm below a projection with a

painted surface, then a heat shield at least 1m long should be fitted.

+. The distance from a fanned draught appliance terminal installed at

right angles to a boundary may be reduced to 300mm

$. Vertical structure includes a chimney-stack, dormer window, tank

room, lift motor room or parapet.



21

Condensation and pluming.

• Facing properties and points of possible extensions in the future must be a

consideration.

• A distance of 2m is recommended where pluming may be a nuisance. To

openings or other properties

Minimum distance to terminal in millimetres

Balanced flue, room-sealed appliance

Natural

draught

Fanned draught

A Directly below an

opening, air brick,

opening window, etc

(0-7 kW) 300 300

(>7-14 kW) 600 300

(>14-32 kW) 1500 300

(>32-70 kW) 2000 300

B Above an opening, air

brick, opening window,

etc

(0-32 kW) 300 300

(>32-70 kW) 600 300

C Horizontally to an

opening, air brick,

opening window, etc

(0-7 kW) 300 300

(>7-14 kW) 400 300

(>14-70 kW) 600 300

POSSIBLE EXTENSION


22

Simple gas faultfinding on appliances

Typical Gas Component Faults on Central Heating

Boilers and Circulators

Unsatisfactory Ignition Of Burners / Flame Supervision

Devices; Flames not igniting,

Explosive ignition due to a range of possible faults;

Pilot flame to small

Pilot flame not in correct position

Faulty FSD

To much gas at the main burner

Not enough gas at the main burner

Unstable Flame Picture

Incorrect flame due to a range of possible faults

Over gassed (Long flames with possible yellow tips)

Lack of oxygen (Yellow flames)

Cracked burners

Blocked burners (Choked with soot)

Signs Of Spillage

Sooting in or around the appliance or appliance seals

Pattern staining from the draught diverter

Inoperative Thermostats Inoperative operating thermostats giving temperature problems (to hot or to

cold)

If operating thermostat fails on a system boiler. The high limit stat will lock

the boiler out (requires to be manually reset)

If high limit stat also fails steaming hot water will discharge from the pressure

relief valve. This will drop the pressure from the boiler. (requires to be

manually reset)

Inoperative Air Pressure Switch

Symptoms on a fan flued boiler would be

The boiler fan starts up but the ignition sequence does not start

( The fan pressure switch starts the ignition sequence)

Inoperative Multifunction Control Valve

a multifunction control valve contains three main components

a FSD,

a Solenoid

a Regulator

all three components must work correctly.


23

Typical Gas Component Faults On

Central Heating Boilers And Circulators






Faulty FSD





Over gassed (Long flames with possible yellow tips)


Cracked burners


Signs Of Spillage



Inoperative Thermostats Inoperative operating thermostats giving temperature problems (to hot or to

cold)

If operating thermostat fails on a system boiler. The high limit stat will lock

the boiler out (requires to be manually reset)

If high limit stat also fails steaming hot water will discharge from the pressure

relief valve. This will drop the pressure from the boiler. (requires to be

manually reset)

Inoperative Air Pressure Switch Symptoms on a fan flued

boiler would be





a FSD,

a Solenoid

a Regulator



24


Cookers






Faulty FSD shut down in (90sec)



Faulty ignition system

Unstable Flame Picture at Full or Simmer


Over gassed ( Long flames with possible yellow tips)


Cracked or warped burners

Blocked burners (Choked with grease)

Faulty Thermostat or Oven By-pass

Thermostat out of calibration and undercooking or overcooking food

Oven burner goes out when the oven reaches temperature (blocked by-pass)

Stiff Burner Control Tap A control tap that is too loose or too tight may require re-greasing

A control tap must also lock itself in the off position so that it cannot be turned

on by accident check the spring and locking collar

Inoperative Lid Closure Device

Lid safety Device must turn the gas of to the burners when the lid is

lowered Some devices turn all the gas taps off others have a reset button to push when

the lid is lifted again. Check that the device operates correctly


25


Space Heating (gas fires)






Faulty FSD







Cracked burners


Signs Of Spillage



Incorrect position of fuel on the fuel bed If the wrong size of radiant or the incorrect amount of coals are used on a gas

fire the result could be

Flame impingement

Incomplete combustion

In either case the burner will not operate correctly, with the appliance

becoming sooted

Inoperable or Stiff control tap Check that the gas tap is easy to work and that it controls the full range of settings on the

appliance






26


Warm Air Units.






Faulty FSD







Cracked burners CRACKED HEAT EXCHANGER/ Blocked burners (Choked with soot)

NO RETURN AIR DUCT

Signs Of Spillage


Pattelkj ;oinern staining from the draught diverter

Inoperative Thermostats Warm air units have a low temperature thermostat this lets the burner turn on

and heat, the heat exchanger before the fan unit turns on.

and a high temperature thermostat this turns the burner off when the heat

exchanger gets too hot, but lets the fan keep running.

If it does not operate in this sequence then the thermostat(s) may be faulty.

Faulty Heat Exchanger

Symptoms of a cracked heat exchanger would be The flame picture is very poor (flames blown side ways)

Products of combustion entering all warm air ducting

Pilot flame blowing out.

Fail spillage test at burner.



a FSD,

a Solenoid

a Regulator



27


Instantaneous Water Heaters






Faulty FSD







Cracked burners


Signs Of Spillage



Scaled Heat Exchanger A scaled heat exchanger usually results in a noisy unit due to the reduction in

flow rate. Also may cause the appliance to over heat





Defective Gas Valve Assembly

Will result in the main burner failing to light or the main burner staying on

after the water has been turned off.

The problem may be:

Defective Diaphragm

Blocked Venturi

Failure of the mechanism (push rod sticking)


28

Volume and purge calculations for large installations With pipework greater than 28mm or a meter bigger than a 6m³ capacity. See www.gb-gas.co.uk for more details.

Installation volume Purge volume

Meter type LENGTH 15mm

LENGTH 22mm

LENGTH 28mm

LENGTH 35mm

Pipe volume m³ Multiply the lengths by the

volumes from table 1

A Total pipe volume This is the same as B

F

Fittings +10% Multiply A by 1.1 to add the

10% on

B Pipework purge volume

x 1.5 Multiply F by 1.5

G

Meter volume Look up the meter volume

C Meter purge volume

(cyclic volume x5)

H

Total installation

volume Add B and C together

D Total purge volume Add G and H together

J

If the volume is greater than 0.035m³ or the meter capacity is

greater than 16m³/hr then the (commercial) IGE UP 1 or 1A

document and qualification must be used.

If the purging volume is less than

0.02m ³ purging is conducted from

the furthest practical point well

ventilated and no source of ignition.

If the purging volume is greater

than 0.02m ³ purging is

conducted from the furthest

practical point and the appliance

must be continually ignited until

a flame is established.

SStteeeell // ssttaaiinnlleessss sstteeeell CCooppppeerr

1155mmmm ½½ 00..0000002244 ((mm³³)) 1155mmmm 00..0000001144 ((mm³³))

2200mmmm ¾¾ 00..0000004466 ((mm³³)) 2222mmmm 00..0000003322 ((mm³³))

2255mmmm 11 00..0000006644 ((mm³³)) 2288mmmm 00..0000005544 ((mm³³))

3322mmmm 11¼¼ 00..00001111 ((mm³³)) 3355mmmm 00..0000008844 ((mm³³))

TTyyppee ooff mmeetteerr FFOORR VVOOLLUUMMEE CCAALLCCSS

MMeetteerr vvoolluummee ((mm³³)) ffoorr ppiippee wwoorrkk

vvoolluummee ccaallccuullaattiioonnss

FFOORR PPUURRGGEE CCAALLCCSS BB

MMeetteerr ccyycclliicc vvoolluummee xx 55 ==MMeetteerr ppuurrggee vvoolluummee iinn ((mm³³))

GG44 // UU66 00..000088 00..000022 xx 55 == 00..001100mm³³

UU1166 00..002255 00.. 000066 xx 55 == 00..003300mm³³

EE66 00..00002244 NN//AA ==00..00003366mm³³



29

Pipe work sizing

Resistance table:

Discharge in straight horizontal table x copper tube with 1.0 mb differential

pressure between the ends, for gas of relative density 0.6 (air = 1).

When estimating the gas flow rate in pipework of a known length this length

must be increased by 0.5 m for each elbow and tee branch fitted.

Draw a plan of your pipe routs SPLIT THE PIPE WORK INTO SECTIONS and number them 1,2,3,4

etc. details on the plan the number of actual or estimated elbows and tees required.

Appliance / appliances 1 2 3 4 5 6

A GAS FLOW REQUIRED THIS IS THE GAS RATE OF THE APPLIANCES THAT THIS PIPE IS

FEEDING

M³/HR

Pipework

B LENGTH (how many meters of pipe) M

C FITTINGS (0.5m for each elbow or

tee going round the corner)

M

D ACTUAL LENGTH (add B+C together)

M

E ASSUMED PIPE DIAMETER

Make an assumption on the pipe diameter or use the table to find a

diameter

MM

F CHART ALLOWABLE LENGTH

Use diameter E in the table read to the

right until you find close to or just

greater than A. then run up to the top

of the table to find the allowable length

M

G PRESSURE DROP

Chart allowable length D divided by

the actual length F. if this is greater

than one you have divided the wrong

number first.

mb

Total Pressure drop

Adding the pressure drops from the meter to the appliances and all pipework it passes must total less

than one to pass eg. (From the meter to the first tee). + (From the tee to the appliance) = must equal less

than 1mb. See www.gb-gas.co.uk for more details.

Meter to appliance 1 Meter to appliance 2 Meter to appliance 3 Meter to appliance 3


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