A-Maize-Ing Heat NRP620-10 Owner's Manual page 36

Problem
Furnace
overheating
Furnace
overheating
Furnace
overheating
Furnace
overheating
Smoke is emitted
during the low fire
cycle
Smoke is emitted
during the high
fire cycle
NRP620-10 OMEPAPV20161017 (ENGLISH) REV 1
Possible Cause
Fuel feed rate too high
If used with another furnace, air
back feeding from the other heat
source may cause overheating.
The hot air output, or cold air
return connections are restricted
or are less than 196 square
inches.
Draft is too high
There is not enough draft.
High pressure in the burn
chamber.
Possible Corrective Action
 Increase the Variable BTU Timer "OFF"
time
 Decrease the Variable BTU Timer "ON"
time
Consult with a heating contractor to install
a device that prevents hot air from feeding
back into the heating appliances.
 Confirm that the hot air output and cold
air return are 196 square inches.
 Check/replace air filter.
 Check for obstructions in the ductwork.
 Check the barometric damper for proper
adjustment. A second damper may be
required in some instances.
 Consult with a heating contractor to check
the flue and chimney operation.
 Check the barometric damper for proper
adjustment to provide sufficient draft
during the low fire cycle.
 Check the flue and chimney installation.
Improper placement of the stack can
cause backflow down the chimney.
 Check the type of vent pipe. In extremely
cold conditions, a poorly insulated vent
pipe can cool and cause air to travel back
into the furnace.
 Check that there is fuel in the fuel feed
system.
 Check that the air bypass is not
obstructed.
 Check the barometric damper for proper
adjustment to provide sufficient draft
during the high fire cycle.
 Check the flue and chimney installation.
Improper placement of the stack can
cause backflow down the chimney.
 Check the type of vent pipe. In extremely
cold conditions, a poorly insulated vent
pipe can cool and cause air to travel back
into the furnace.
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