LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
30
13. Turn the knob on the pilot valve to on, Figure 18.
14. Turn on all electric power to the boiler and set the operating
control or thermostat to the desired setting.
15. With the unit operating at high purge the differential air pressure
should match those listed in Table 15. To adjust the differential
air pressure see the “AIRFLOW ADJUSTMENT” instructions
in the “CHECKING AND ADJUSTMENTS” section.
Figure 19
Manual valve & manifold pressure tap
16. The pilot should automatically light. Do not try to light the
pilot by hand!
17. The pilot pressures should match those listed in Table 20. To
adjust the pilot gas pressure see the “PILOT ADJUSTMENT”
instructions in the “CHECKING AND ADJUSTMENTS”
section.
18. Distinguish pilot.
19. Turn the knob on the main gas valve to on, 400 model, Figure
18. On 600 through 2300 models open the manual shutoff
valve located in the control compartment, Figure 19.
20. Recycle boiler.
21. The manifold pressures should match those listed in Table 20.
To adjust the manifold gas pressure see the “GAS PRESSURE
ADJUSTMENT” instructions in the “CHECKING AND
ADJUSTMENTS” section.
22. Replace the upper front jacket panel.
23. Check all safety switches for proper operation before placing
boiler on-line.
LP
Nat
Minimum (in WC)
11
7
Maximum (in WC)
14
14
Measure pressure when the boiler is firing at full rate. Low gas
pressure could indicate undersized gas line or insufficient gas supply.
Static and operating gas pressure required at the gas valve inlet is
between 7 in WC and 14 in WC for natural gas and 11 in WC and
14 in WC for propane. If the gas pressure is above this limit, a lock-up
style regulator suitable for dead end service such as an Equimeter or
Fisher must be installed to prevent increase (creep) of gas pressure
when the units are not operating. This pressure regulator (supplied
by others) may be installed at the service entrance to each unit or
a “master” regulator sized to handle multiple units may be utilized.
Consult local gas utility or regulator manufacturer for recommenda-
tions to meet specific job site requirements.
Table 20 Pilot & manifold pressures
On/Off
inches WC
mm WC
Pilot - NG
2.5 ± 0.3
63.5 ± 7.6
Pilot - LP
7.0 ± 2.0
177.0 ± 50.0
Low Fire
inches WC
mm WC
Manifold - NG
1.4 ± 0.2
35.5 ± 5.0
Manifold - LP
4.0 ± 0.5
101.6 ± 12.7
High Fire
inches WC
mm WC
Manifold - NG
2.5 ± 0.2
63.5 ± 5.0
Manifold - LP
9.3 ± 0.3
236.2 ± 7.6
Table 21 Combustion readings
Natural Fuel
Propane Fuel
CO
2
%
7.0 - 7.5 (low)
8.2 - 8.8 (low)
7.8 - 8.5 (high)
9.2 - 9.9 (high)
O
2
%
8.3 - 7.6 (low)
8.3 - 7.6 (low)
7.0 - 5.8 (high)
7.0 - 5.8 (high)
Required Gas Pressure
Provide gas supply pressure at inlet to boiler gas train as follows:
