74
Rev. 05/2020
PROBLEM
CAUSE
SOLUTION
REFERENCE
Furnace boils
or rattles before
reaching maximum
Temp.
HTF Temperature
range to broad
Reduce
Temperature
“Electrical (HTF
Temperature Range
Control)”
Operating
temperature to high
Maximum temp.
setting should not
exceed 180° F
“Electrical (HTF
Temperature Range
Control)”
Firebox Door
pops or Rattles
Loading fuel too
close to the firebox
door
Load your fuel away
from the firebox
door
“Loading Coal into
the HEATMOR™
HTF Temp. range
setting is too wide
Adjust aquastat
spread setting
closer
“Electrical (HTF
Temperature Range
Control)”
Building
too warm
Defective in-house
thermostat
Replace thermostat
Local Dealer
Aquastat
malfunction
Replace Aquastat
“Electrical (HTF
Temperature Range
Control)”
Outdoor furnace is
overheating
Check for air leaks
“Checking for Air
Leaks”
Controls for heating
appliances in building
need to be adjusted
Adjust, relocate,
add more controls
to monitor & control
Heat
Local Dealer
Creosote Build-Up
Air leakage
around door
Replace Door
Gasket
“Firebox Door
Gasket”
Firebox receiving air
somewhere when
fans are off
Check all seals for air
leaks. Run a smoke
check
“Checking for Air
Leaks”
Fire is not
burning hot
Check type of coal
burning & if blowers
working properly
“
Types of Coal,
Combustion Air
Blowers/ Flipper
Assemblies”
Air flow is not
sufficient for the
type of fuel
Check and clean fan
blades. Check & clean
flipper assembly
“Combustion Air
Blowers/ Flipper
Assemblies”