34
SECTION 10
LPG INSTRUCTIONS
10.1 RELATED DOCUMENTS
BS 5440
PARTS 1 & 2
FLUES & VENTILATION REQUIREMENTS
BS 5449
PART 1
FORCED CIRCULATION OF HOT WATER SYSTEMS
BS 5482
PART 1
DOMESTIC BUTANE & PROPANE GAS BURNERS IN PERMAMENT
DWELLINGS
BS 5546
INSTALLATION OF GAS HOT WATER SUPPLIES FOR DOMESTIC
PURPOSES
BS 6798
INSTALLATION OF BOILERS OF RATED NOT EXCEEDING 60kW
10.2
Gas Pressures
Unica 28HE
Unica 32HE
Unica 36HE
I
nlet pressure
37.0mbar
Maximum gas rate (kg/hr)
2.17
2.48
2.80
Minimum gas rate (kg/hr)
0.47
0.54
0.54
Injector size
4.7mm
4.7mm
5.0mm
CO
2
max (%)
10.0
10.0
10.0
CO
2
min (%)
10.0
10.0
10.0
CO max (mg/kWh)
182.8
215.0
236.5
CO max (mg/kWh)
32.3
21.5
21,5
NOx max (PPM) mg/kWh
70.6
88.3
88.3
NOx min (PPM) mg/kWh
53.0
53.0
70.6
CO/CO
2
ratio @ max
0.002 to 1
0.002 to 1
0.002 to 1
CO/CO
2
ratio @ min
0.002 to 1
0.002 to 1
0.002 to 1
SEDBUK ‘A’ (%)
92.4
92.7
92.7
10.3
CONVERTING THE APPLIANCE GAS TYPE
To convert the appliance to another gas type it is
necessary to change the burner injector, adjust
the appliance fan speeds, and adjust the gas
valve (CO
2
).
•
To change the injector see 6.12.1
•
To adjust the fan speeds see 10.7
•
To adjust CO2 values see 10.6
10.4
GAS SUPPLY
The gas supply must be connected to the
appliance by a competent LPG installer and must
be of sufficient size to supply the appliance at its
maximum output. An existing supply must be
checked to ensure that it is of adequate size to
deal with the maximum rated input of this and
any other appliances that it serves.
10.5
GAS SUPPLY INSTALLATION
The entire installation including the meter must
be purged and checked for gas soundness.
10.6
ADJUSTING THE GAS VALVE
THE GAS VALVE MUST BE SET-UP OR
ADJUSTED WITH THE AID OF A PROPERLY
CALIBRATED FLUE GAS ANALYSER.
10.6
CHECKING THE CO2 AND ADJUSTING THE
GAS VALVE
THE GAS VALVE MUST BE SET-UP OR
ADJUSTED WITH THE AID OF A PROPERLY
CALIBRATED FLUE GAS ANALYSER.
Isolate the appliance from the electrical supply
and remove the appliance casing as described in
4.7.1. Set the flue gas analyser to read CO2 and
insert the probe into the flue analysis test point (
A,
B
fig. 35). Restore the electrical supply to the
boiler and switch the boiler to the OFF mode. To
adjust the gas valve you must first ensure that the
fan speed potentiometers (trimmers) have been
set correctly (see 10.7).
Remove the 3-selector knobs, locate and press
the CO button (see fig. 36). The appliance will now
operate in CO mode for approximately 15-minutes
(see 7.10).
10.6.1 GAS VALVE MAXIMUM SETTING
Locate and gently turn the HTG trimmer till the
maximum value (fan speed) is obtained and check
that it corresponds with the appropriate CO2 value
(Maximum) for the respective appliance. If the CO2
reading is correct, proceed to gas valve minimum
setting (10.6.2).
However, If the CO2 reading is incorrect, the
maximum gas pressure must be adjusted as
follows:
•
Using a 2.5mm Allen key, very slowly turn the
maximum adjustment screw (see fig. 38) –
clockwise to decrease, counter clockwise to
increase – until the correct value is displayed on
the CO2 analyser (allow time for the analyser to
stabilise).
10.6.2 GAS VALVE MINIMUM SETTING
Locate and gently turn the HTG trimmer till the
minimum value (fan speed) is obtained and check
that it corresponds with the appropriate CO2 value
(Minimum) for the respective appliance. If the CO2
reading is correct, rotate the HTG trimmer until
the correct value is obtained for the respective
appliance (see fan speed table) and proceed to
10.6.3.
However, If the CO2 reading is incorrect, the
minimum gas pressure must be adjusted as follows:
•
Using a suitable screwdriver, very slowly turn
the minimum adjustment screw (see fig. 38) –
clockwise to increase, counter clockwise to
decrease - until the correct value is displayed on
the CO2 analyser (allow time for the analyser to
stabilise).
10.6.3 COMPLETION
On completion of the combustion analysis check
and/or any gas valve adjustment, set the HTG
trimmer to the corresponding value as detailed in
the fan speed table. Refit the 3-selector knobs and
move the mode selector to the OFF position.
Remove the test probe from the test point and refit