Specifications

Heartland Owners Forum http://manuals.heartlandowners.org
Heating and Cooling Guide V1.pdf Page | 15 Version: 1, March 15, 2013
Furnace Operation
Normal Sequence and Theory of Operation
When the thermostat is set to heat mode and the sensed temperature falls below the thermostat set
point, the furnace will start. First, the fan comes on for about 20 seconds. This is to purge the
combustion chamber of any potential gas. There is an air flow switch (sail switch) that must close before
the furnace will even attempt to light. Next the gas valve will open and the direct spark igniter will light
the main burner. A flame sensor checks for successful ignition. If the flame sensor does not detect the
burner being lit within a few seconds of the gas valve opening, the gas valve is closed and the fan will
run for about 60 seconds to purge any propane gas from the combustion chamber. This cycle will
continue for 3 or 4 attempts. After several unsuccessful tries at ignition, the furnace controller will lock
out and will not attempt to re-light until you cycle the thermostat to OFF and back ON.
If you’re not on shore power (converter powered) and your batteries are getting low on power, the fan
may come on but not move enough air to close the sail switch. In this case, the gas valve will not open
and the ignition sequence will not take place.
As the furnace runs, there will be a large amount of “waste” heat blowing out of the exhaust port of the
furnace outside. This is the combustion gas exhaust from the furnace and is normal.
If you see any buildup of soot around the exhaust port, this is a warning sign of improper flame
adjustment and that service is required.
When the temperature in your coach warms up sufficiently, the thermostat shuts the furnace off. The
gas valve closes, but the fan will continue to run until the burner has cooled down and the exhaust gases
have been purged from the combustion chamber.
Using Electric Heat
With the high price of propane and the inconvenience of filling propane tanks, you may want to consider
electric heat alternatives that can reduce the furnace runtime. If you are in a spot where the electric
use is included in site rental, using a heat pump, an electric fireplace, ceramic disc heaters, or similar
devices will reduce your camping cost.
Note that a fireplace or ceramic disc heater can require up to 15 amps of electric service. If you plug
them into outlets that are shared with other appliances, you could trip the circuit breaker. If you plan
on regular use of devices like these, it’s advisable to have a dedicated outlet and circuit breaker
installed.
CAUTION: In sub-freezing weather, running the furnace is the only way to pump heated air into
the underbelly. By running auxiliary heating devices, the furnace will usually not run as much,
and the underbelly will not be as warm. This could lead to parts of your plumbing system or
holding tanks freezing. It’s advisable to monitor underbelly temperature with a remote sending
thermometer.