508134-01
Issue 2045
Page 41 of 53
4.
Move gas valve switch to OFF.
5.
Replace the access panel.
Failure To Operate
If the unit fails to operate, check the following:
1.
Is the thermostat calling for heat?
2.
Are access panels securely in place?
3.
Is the main disconnect switch closed?
4.
Is there a blown fuse or tripped breaker?
5.
Is the filter dirty or plugged? Dirty or plugged filters will
cause the limit control to shut the unit off.
6.
Is gas turned on at the meter?
7. Is the manual main shut-off valve open?
8.
Is the internal manual shut-off valve open?
9. Is the unit ignition system in lockout? If the unit locks
out again, inspect the unit for blockages.
Heating System Service Checks
C.S.A. Certification
All units are C.S.A. design certified without modifications.
Refer to the
GDD92C
Operation and Installation
Instruction.
Gas Piping
If a flexible gas connector is required or allowed by
the authority that has jurisdiction, black iron pipe shall
be installed at the gas valve and extend outside the
furnace cabinet. The flexible connector can then be
added between the black iron pipe and the gas supply
line.
CAUTION
Do not over torque (800 in-lbs) or under torque (350
in-lbs) when attaching the gas piping to the gas valve.
WARNING
Gas supply piping should not allow more than 0.5” W.C.
drop in pressure between gas meter and unit. Supply gas
pipe must not be smaller than unit gas connection.
Compounds used on gas piping threaded joints should be
resistant to action of liquefied petroleum gases.
Testing Gas Piping
In case emergency shutdown is required, turn off the
main shut-off valve and disconnect the main power to
unit. These controls should be properly labeled by the
installer.
IMPORTANT
When pressure testing gas lines, the gas valve must be
disconnected and isolated. Gas valves can be damaged if
subjected to more than 0.5 psig (14” W.C.). See Figure 50.
Figure 50.
MANUAL MAIN SHUT-OFF
VALVE WILL NOT HOLD
NORMAL TEST PRESSURE
CAP
FURNACE
ISOLATE
GAS VALVE
1/8” N.P.T. PLUGGED TAP
When checking piping connections for gas leaks, use
preferred means. Kitchen detergents can cause harmful
corrosion on various metals used in gas piping. Use of a
specialty Gas Leak Detector is strongly recommended.
Do not use matches, candles, flame or any other source
of ignition to check for gas leaks.
WARNING
Gas Flow (Approximate)
Capacity
Seconds for One Revolution
Natural
LP
1 cu ft
Dial
2 cu ft
Dial
1 cu ft
Dial
2 cu ft
Dial
-45
80
160
200
400
-70
55
110
136
272
-90
41
82
102
204
Natural-1000 btu/cu ft LP-2500 btu/cu ft
Table 14. Gas Meter Clocking Chart
Furnace should operate at least 5 minutes before checking
gas flow. Determine time in seconds for two revolutions of
gas through the meter. (Two revolutions assures a more
accurate time.) Divide by two and compare to time in Table
14. If manifold pressure matches Table 16 and rate is
incorrect, check gas orifices for proper size and restriction.
Remove temporary gas meter if installed.
NOTE:
To obtain accurate reading, shut off all other gas
appliances connected to meter.
