HEATING & AIR CONDITIONING
HOW THE HEAT PUMP THERMOSTAT WORKS.
The RvComfort.HP, the RvComfort.PHP, the Coleman True-air, and the RvComfort.ZC thermostats by
RvProducts Inc. are all capable of running not only an Air Conditioning unit, but also an Electric Heat
Pump. Frequently we receive calls from customers who do not understand the functions of the Heat
Pump Thermostat. This guide is a quick run through of the information already provided in the
Thermostat Operation Manual, included with each thermostat.
The Heat Pump is an electric source of heat. IT will supply and maintain heat assuming the outside
(ambient) temperature is above 40 degrees. This number of course can be slightly higher or lower
depending on the humidity. Higher humidity can cause a heat pump to lose efficiency at higher ambient
temperature, while lower humidity can cause a heat pump to lose efficiency at a lower ambient
temperature.
Since no one wants to wake up to find that the outside temperature has dropped below 40 degrees and it
is now 50 degrees in the coach, the Heat Pump thermostats are programmed internally to recognize
when the temperature drops five degrees or more from the set temperature to the actual inside room
temperature. When the temperature exceeds five degrees or more between the two, the thermostat will
default to the next available heat source.
The thermostat, upon sensing a temperature split of five degrees or more in the electric heat mode will
bring the gas heat on to assist the electric heat. This is the first strike. A strike is created by the thermostat
having to change modes (or run dual modes to sustain a temperature split). The electric heat and gas
heat will continue to run together until the thermostat reaches the set temperature and satisfies. When
the electric heat comes back on. It will be in electric heat only at that point. If the temperature again
drops five degrees or more from the set point, the thermostat will again bring on the gas heat to assist.
This is strike two. The system will then go through the above stated procedures. If the temperature
should drop five more degrees from the set point or a third time, the thermostat will give up the electric
heat, lock the electric heat out for two hours (showing either DIFF on the display or FLASHING GAS
HEAT on the display) and default to GAS heat only. You WILL NOT be able to run any Electric Heat
during this two-hour lockout.
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