Checking & Adjustments; Pilot Adjustment - RBI Gas boilers Installation And Operation Instructions Manual

Finned copper tube gas boilers & water heaters – Boiler Manual Finned copper tube gas boilers & water heaters – Boiler Manual F
CHECKING & ADJUSTMENTS
Spark Gap
With the main and pilot gas manual valves in the closed position
energize the unit. Observe the trial for ignition to confi rm that the
spark is strong and continuous. If not check and adjust the spark
gap as shown in Figure 17.
Figure 17 Spark Gap

Pilot Adjustment

Th e pilot pressure has been factory set at 3 in for natural and LP
gas and shouldn't need adjustment. To check the pilot pressure
close the manual main shut-off valve 2 and the pilot gas shut-off
valve, Figure 14. Remove the 1/8 in pipe plug from the pilot tee
and connect a manometer having a minimum range of 6 in,
152 mm WC to it. Open the pilot gas shut-off valve. With the unit
powered, generate a call for heat. When the prepurge is complete
the ignition/pilot trial will begin. At this point put the Honeywell
RM7800 test switch in the test position. Th e control will hold in
the ignition/pilot sequence allowing you to check the pressure.
To adjust the pilot the following steps must be taken:
1. Remove the pilot gas pressure regulator cap.
2. Turn the pressure regulator adjustment screw clock-wise to
increase the pressure and counterclockwise to decrease it.
3. Replace the pressure regulator adjustment screw cap.
Never force the regulator adjustment screw beyond the stop
limits or damage to the regulator will occur!
Th e air damper adjustments must only be made by
a trained technician using a combustion analyzer!
Improper adjustment can result in excessive levels of
carbon monoxide or an explosion resulting in severe
personal injury or death!
Required Gas Pressure
Provide gas supply pressure at inlet to boiler gas train as follows:
Minimum (in WC)
Maximum (in WC)
Measure pressure when the boiler is fi ring at full rate. Low gas
pressure could indicate undersized gas line or insuffi cient gas supply.
"Static and operating gas pressure required at the gas valve inlet
is between 2 in WC and 14 in WC for natural gas and 2 in WC and
14 in WC 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 and not to exceed a maximum of
(10 in WC) drop when fi ring from minimum input to supply line
and all the appliances running. Th is pressure regulator (supplied by
others) may be installed at the service entrance to each unit or
a "master" regulator sized to handle multiple units with adequate
turndown capability may be utilized. Consult local gas utility or
regulator manufacturer for recommendations to meet specifi c job
site requirements. "
Input Rate, Natural Gas
Gas appliances are rated based on sea level operation with no adjust-
ment required at elevations up to 2000 ft , 610 m. At elevations
above 2000 ft , 610 m input ratings should be reduced by 4% for
each 1000 ft , 305 m.
Check the input rate as follows:
1. Turn off all other gas appliances that use the same gas meter
as the boiler/water heater.
2. Call your gas supplier and ask for the heating value of the gas.
3. Start the boiler/water heater and let it run for 15 minutes.
4. Using the gas meter and a stopwatch, clock the time that it
takes to burn 10 ft 3 , 0.28 m
5. Insert the heating value and the time, in seconds, into the formula
below.
6. Input = (heating value, Btu/hr)(3600)/(time, seconds)
7. If the computed rate deviates by more than 5% from the rated
input value of the unit, consult factory.
Never increase the input to the boiler/water heater above that
for which it is rated. Doing so can cause premature failure of
the boiler!
LP Nat
2 2
14 14
3 of gas and divide this time by 10.
25