Glowworm Ultracom 24cx User manual

Technical Helpline: 01773 828300
Glow-worm, Nottingham Road, Belper, Derbyshire. DE56 1JT
www.glow-worm.co.uk
0020088542-03 02.10
GAS VALVE(DUNGS)
KIT Pt. No. 2000802664
6mm white scroll incl.
Brass Flange adaptor, 4
off screws, 2 “O” rings
MODEL
24 & 30 ultracom cx
24 & 30 ultracom cxi
18 & 30 ultracom sxi
18 & 30 sxi
24 & 30cxi
MODEL
12 – 30 hxi
12 – 30 ultracom hxi
MODEL
38 cxi
38 ultracom cxi
Xtramax HE
MODEL
38 hxi
38 ultracom hxi
BG330
KIT Pt. No 2000802442
6mm white scroll
incl. Brass liner
and grommet
KIT Pt. No 2000802452
12mm grey scroll
incl. Brass liner
and grommet
KIT Pt. No. 0020018823
12mm grey scroll incl.
Brass Flange adaptor,
4 off screws, 2 “O” rings
If the burner door is removed during the gas valve
replacement a new door seal must be tted.
Burner Door Seal kit - Part No. 801635
IMPORTANT NOTES
THESE INSTRUCTIONS SUPERCEDE
THE GAS VALVE SETTING PROCEDURE CONTAINED
WITHIN THE ORIGINAL APPLIANCE LITERATURE.

Requirements
It is the Law that any replacement of parts is carried out by a
competent person approved at the time by the Health and Safety
Executive.
Before commencing with the replacement of a part the boiler
should be isolated from the electrical supply and the gas supply
should be turned off at the gas isolation valve.
When replacing a part, use only spare parts that you can be
assured conform to the safety and performance specification that
we require. Do not use reconditioned or copy parts that have
not been clearly authorised by Glow-worm.
After electrical connections have been made, checks to the
earth continuity, polarity, short circuit and resistance to earth
must be repeated using a suitable multimeter.
Unless stated otherwise, parts are replaced in the reverse order
to their removal.
After replacing these parts you MUST always test for gas
soundness and carry out functional test of the controls and
check the following:
General Inspection
After the replacement of a part, the following must be
checked.
● The integrity of the flue system and flue seals.
● The integrity of the appliance combustion circuit and
relevant seals.
● Electrical, gas and water connections.
● System pressure.
● the combustion performance, operational gas inlet
pressure and gas rates.
refer to the following procedure.
ALL MODELS
Refer to the installation and servicing instructions supplied
with your boiler to t the replacement gas valve.
IMPORTANT. If the Burner Door was Removed
Fit the new combustion door seal kit tted in accordance
with the instructions provided.
Re- assembly
After assembly test for gas soundness and purge in
accordance with the current issue of BS6891 or in IE, the
current edition of I.S.813 “Domestic Gas Installations”.
Do not t the inner or front case until the commisioning has
been carried out as described in the following sections.
COMPETENCY TO CARRY OUT THE CHECK
OF COMBUSTION PERFORMANCE
NOTE: BS 6798: 2009 Specication for installation
and maintenance of gas-red boilers of rated input not
exceeding 70kW net advises that:
● The person carrying out a combustion measurement
must be assessed as competent in the use of a ue gas
analyser and the interpretation of the results.
● The ue gas analyser used should be one meeting
the requirements of BS7927 or BS-EN50379-3 and be
calibrated in accordance with the analyser manufacturers’
requirements.
● Competence can be demonstrated by satisfactory
completion of the CPA1 ACS assessment, which covers
the use of electronic portable combustion gas analysers in
accordance with BS 7967, parts 1 to 4.
● Ensure that the gas analyser is set to the correct fuel
setting.
NOTE: Safe combustion can only be verified by measuring CO/
CO2 ratio. This must not exceed the value shown in the table on
the back page.
FLUE
ELBOW
COMBUSTION
ANALYSER
TEST POINT
FLUE
DUCT
Diagram 1
COMBUSTION
ANALYSER
TEST POINT
Diagram 2
OFFSET
ADJUSTMENT
2mm Allen Key
THROTTLE
Flat Bladed or
2mm Allen Key

LPG MODELS - ONLY
Refer to diagram 2 and turn the gas valve throttle
fully clockwise, then turn the throttle anti-clockwise by the
number of turns shown in the table on the back page.
Please refer to the specic instruction relating to your
model.
1. Turn on the electrical supply.
2. Ensure external controls are calling for heat.
3. Turn on the gas supply.
4. Turn on the appliance.
5. The boiler should re automatically.
NOTE: LPG MODELS
If the appliance does not light & goes to lockout (F1), turn
the throttle anti-clockwise 1 full turn. Reset the appliance.
The appliance will (after a short delay) again attempt to
re. If necessary, repeat this procedure up to a total of 2
extra turns on the throttle screw, until the appliance lights.
Several ignition attempts may be needed, to purge gas
through the appliance, before a successful ignition is
achieved.
ALL MODELS
With the appliance cold.
Connect a CO2 combustion analyser to the appropriate
test point, see diagrams 1.
Maximum Rate Check and Adjustment
Refer to the instructions supplied with your appliance and set the
maximum rate.
Check and adjust CO2 as necessary.
NOTE: Adjustment is made by turning the throttle an
⅛ of a turn, waiting 1 minute to allow the appliance
to stabilise before checking or making further
adjustments.
● Rotate the “throttle”(anti-clockwise to increase), to the
required CO2, refer to diagram 2 and the “SETTING”
column in the table.
● Now proceed to check the minimum rate adjustment.
Set appliance to minimum rate.
Minimum Rate Check and Adjustment
Refer to the instructions supplied with your appliance and set the
minimum rate.
Check and adjust CO2 as necessary.
Adjustment is made by turning the offset adjustment, see
diagram 2.
If adjustment is necessary, proceed as follows:
NOTE: Adjustment of the CO2 at minimum rate is very
coarse and should not be adjusted more than an ⅛ of
a turn at a time. Wait 1 minute to allow the appliance
to stabilise before checking or making further
adjustments.
● Gradually rotate the “offset adjustment” (anti-clockwise
to decrease) to the required CO2, refer to diagram 2 and
the “SETTING” column in the table.
Re-Check CO2 and check the CO/CO2
combustion ratio.
● Re-check the maximum and minimum CO2 values to
ensure that they are within the “setting” limits in the table
then check the CO/CO2 combustion ratio does not exceed
the value in the CO/CO2 column of the table. If the CO/
CO2 setting exceeds the value in the table, a complete
servicing of the appliance will be necessary, refer to the
servicing instructions
Check the Gas Inlet Pressure and Gas Rate
On completion, test the gas installation for tightness using
the pressure drop method and suitable leak detection uid,
purge in accordance with the above standard.
NOTE: Due to the modulating operation of the boiler and
the need to check the gas inlet pressure and measure the
gas rate at maximum rate, it will be necessary to force it to
maximum.
Operational Gas Inlet Pressure
With ALL other gas appliances operating, check the
operational supply pressure at the gas service isolation
valve test point, refer to your Installation literature supplied
with your appliance.
The nominal supply pressure for Natural Gas (G20) is
20mbar.
The nominal supply pressure for LPG (G31) is 37mbar.
Turn the taps and appliances off, then disconnect the
pressure gauge.
Additionally the safe nominal maximum heat input of the
appliance can be achieved at an inlet pressure down to
15mbar.
NOTE: The BURNER PRESSURE cannot be measured
and is not used to measure the gas rate.
Gas Rate
Make sure that ALL other gas burning appliances and pilot
lights are off.
Check the gas rate using the gas meter test dial and stop
watch, at least 10 minutes after the burner has lit, see
table below for approximate rates.
In communal or LPG installations where the gas rate
cannot be measured it is acceptable to measure the
combustion rate as described in the servicing section.
On completion, reset the boiler to normal operation by
referring to the Installation and Servicing Instructions.
Completion
If it is not possible to achieve the required results for
either the combustion or gas rates, it will be necessary to
complete a full service of the appliance and then repeat
the combustion check procedure. If after servicing and
adjustment of the appliance the combustion values are still
unacceptable and after further remedial work has been
carried out, the appliance must be disconnected until the
CO/CO2 ratio is acceptable. Advice can be sought from
the Glow-worm Technical Helpline.

Models SETTING SETTING Throttle CO/CO2
Nat. Gas G20 - Case Off Propane G31 - Case Off turns
Because of our constant endeavour for improvement, details may vary slightly from those shown in these instructions.
% CO2 TABLE
m3/h ft/h kg/hr
Models GAS RATES - Nat. Gas G20 GAS RATES - Propane G31
MAX MAX
Glow-worm 24cxi 9.1%CO2 (+0.2% -0.5%) N/A N/A N/A
Glow-worm 30cxi 9.1%CO2 (+0.2% -0.5%) 10.5%CO2 (+0.2% -0.2%) 5
1
/2 0.004
Glow-worm 38cxi 8.8%CO2 (+0.2% -0.5%) N/A N/A N/A
Glow-worm 18sxi 9.1%CO2 (+0.2% -0.5%) N/A N/A N/A
Glow-worm 30sxi 9.1%CO2 (+0.2% -0.5%) 10.5%CO2 (+0.2% -0.2%) 5
1
/2 0.004
Glow-worm 12hxi 9.1%CO2 (+0.2% -0.5%) N/A N/A N/A
Glow-worm 15hxi 9.1%CO2 (+0.2% -0.5%) N/A N/A N/A
Glow-worm 18hxi 9.1%CO2 (+0.2% -0.5%) N/A N/A N/A
Glow-worm 24hxi 9.1%CO2 (+0.2% -0.5%) N/A N/A N/A
Glow-worm 30hxi 9.1%CO2 (+0.2% -0.5%) 10.5%CO2 (+0.2% -0.2%) 5
1
/2 0.004
Glow-worm 38hxi 8.8%CO2 (+0.2% -0.5%) N/A N/A N/A
BG 330 9.1%CO2 (+0.3% -0.3%) N/A N/A N/A
Ultracom 24cx 9.1%CO2 (+0.2% -0.5%) 10.0%CO2 (+0.0% -0.9%) 5
1
/4 0.004
Ultracom 30cx 9.1%CO2 (+0.2% -0.5%) 10.5%CO2 (+0.3% -0.7%) 5
1
/2 0.004
Ultracom 24cxi 9.1%CO2 (+0.2% -0.5%) 10.0%CO2 (+0.0% -0.9%) 5
1
/2 0.004
Ultracom 30cxi 9.1%CO2 (+0.2% -0.5%) 10.5%CO2 (+0.3% -0.7%) 5
1
/2 0.004
Ultracom 38cxi 8.8%CO2 (+0.2% -0.5%) 9.8%CO2 (+0.2% -0.8%) 8 0.004
Ultracom 18sx 9.1%CO2 (+0.2% -0.5%) 10.1%CO2 (+0.0% -1.0%) 5 0.004
Ultracom 30sx 9.1%CO2 (+0.2% -0.5%) 10.5%CO2 (+0.3% -0.8%) 5
1
/2 0.004
Ultracom 12hxi 9.1%CO2 (+0.2% -0.5%) 10.1%CO2 (+0.0% -0.8%) 5 0.004
Ultracom 15hxi 9.1%CO2 (+0.2% -0.5%) 10.1%CO2 (+0.5% -0.5%) 5
1
/4 0.004
Ultracom 18hxi 9.1%CO2 (+0.2% -0.5%) 10.1%CO2 (+0.0% -1.0%) 5 0.004
Ultracom 24hxi 9.1%CO2 (+0.2% -0.5%) 10.1%CO2 (+0.3% -0.8%) 5
1
/4 0.004
Ultracom 30hxi 9.1%CO2 (+0.2% -0.5%) 10.5%CO2 (+0.3% -0.8%) 5
1
/2 0.004
Ultracom 38hxi 8.8%CO2 (+0.2% -0.5%) 9.8%CO2 (+0.2% -0.8%) 8 0.004
Xtramax HE 9.0%CO2 (+0.2% -0.2%) 10.1%CO2 (+0.2% -0.2%) 5
1
/2 0.004
Glow-worm 24cxi 2.24 79 - - -
Glow-worm 30cxi 2.80 99 - - -
Glow-worm 38cxi 3.6 127 - - -
Glow-worm 18sxi 2.0 71 - - -
Glow-worm 30sxi 3.0 107 - - -
Glow-worm 12hxi 1.30 46 - - -
Glow-worm 15hxi 1.63 57 - - -
Glow-worm 18hxi 2.24 99 - - -
Glow-worm 24hxi 2.46 87 - - -
Glow-worm 30hxi 2.80 99 - - -
Glow-worm 38hxi 3.6 127 - - -
BG 330 1.9 66.4 - - -
Ultracom 24cx 2.24 79 - 1.88 -
Ultracom 30cx 2.80 99 - 2.34 -
Ultracom 24cxi 2.24 79 - 1.88 -
Ultracom 30cxi 2.8 99 - 2.34 -
Ultracom 38cxi 4.06 143 - 2.98 -
Ultracom 18sx 2.0 71 - 0.48 -
Ultracom 30sx 3.0 107 - 0.48 -
Ultracom 12hxi 1.29 45.6 - 0.48 -
Ultracom 15hxi 1.61 57 - 0.48 -
Ultracom 18hxi 2.00 70.6 - 1.47 -
Ultracom 24hxi 2.58 91.1 - 1.90 -
Ultracom 30hxi 3.02 107 - 2.22 -
Ultracom 38hxi 4.06 143 - 2.98 -
Xtramax HE 3.62 128 - 2.66 -