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Finned copper tube gas boilers & water heaters – Boiler manual
FTXLF-IOM-HN-1-110308 Copyright 2008 Mestek, Inc.
pilot adjustment
The pilot pressure has been factory set at 3 inches w.c., and
1.
shouldn't need adjustment.
To check the pilot pressure close the manual main shut-off
a.
valve 2 and the pilot gas shut-off valve, Figure 16, page 22.
Remove the 1/8-inch pipe plug from the pilot gas pressure
b.
regulator cap and connect a manometer having a minimum
range of 6 inches, 152 mm w.c. to it.
Open the pilot gas shut-off valve.
c.
With the boiler powered, generate a call for heat.
d.
When the prepurge is complete the ignition/pilot trial will
e.
begin.
Put the Honeywell RM7800 test switch in the test position.
f.
The control will hold in the ignition/pilot sequence, allowing
you to check the pressure.
To adjust the pilot the following steps must be taken:
2.
Remove the pilot gas pressure regulator cap.
a.
Turn the pressure regulator adjustment screw clock-wise to
b.
increase the pressure and counterclockwise to decrease it.
Replace the pressure regulator adjustment screw cap.
c.
Never force the regulator adjustment screw beyond the
stop limits or damage to the regulator will occur!
required gas pressure
Provide gas supply pressure at inlet to boiler gas train as follows:
Gas supply pressure
Inches
water column
mm
water column
Minimum (in W.C.)
3.5
88.9
Maximum (in W.C.)
14
356
Measure pressure when the boiler is firing at full rate. Low
1.
gas pressure could indicate undersized gas line or insufficient
gas supply.
Static and operating gas pressure required at the gas valve inlet is
2.
listed in the Table above.
If the gas pressure is above the limit above, a lock-up
style gas pressure 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 recommendations to meet specific
job site requirements.”
input rate — natural gas
Gas appliances are rated based on sea level operation with
no adjustment 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:
Turn off all other gas appliances that use the same gas meter as
1.
the boiler/water heater.
Call your gas supplier and ask for the heating value
2.
of the gas.
Start the boiler/water heater and let it run for 15 minutes.
3.
Using the gas meter and a stopwatch, clock the time that it takes
4.
to burn 10 ft
3
, 0.28 m
3
of gas and divide this time by 10.
Insert the heating value and the time, in seconds, into the formula
5.
below.
Input = (heating value, Btu/hr)(3600)/(time, seconds)
6.
If the computed rate deviates by more than 5% from the rated
7.
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!
