So you have the choice of "prefer gas" or "prefer heat pump" to switch. The prefer gas will always use gas furnance from what I can tell. Prefer heat pump will use the heat pump until the temperature falls below 8 degrees of what your setting is. Example if you have prefer heat pump and your temperature is set to 68 degress, heat pump will be used until the temperature drops below 60 in the rv. Then gas furnace will kick on.Newbie question:
How does one cycle between the heat pump and furnace?
On shakedown trip now, it was chilly around 40 last night.
Is there a level of temp monitoring going on so the thermostat chooses based on ambient temps, or other?
Checked manual, control panel, thermostat, etc - no obvious answer like with the water heater!
Thank you, but where/how?! I seem to be on prefer gas right now.
With heat pumps, it's important to understand that they're only about as efficient at heating as at cooling. An air conditioner might be designed to cool 20 F, that is to go from 95 F outside to 75 F inside. That same temperature differential would only be able to heat from 45 F to 65 F, so if you need three air conditioners, then three heat pumps will still not be enough to keep your RV warm in really cold weather. In addition, heat pumps are less efficient at lower temperatures, so you're going to need some additional heating if it's very cold.
You have a bit of misunderstanding about that "20° differential" in your explanation above. An air cond. is considered to be doing a good job of cooling if it can achieve a 20°F temperature differential between the inlet air and the discharge air........not the inside air and the outside air.
Yes, but it isn't when the AC can't cool the air any longer that we're worried about, it's when it can't cool it any FURTHER, and that's what the user is usually concerned with. Some states have laws that the AC must be able to cool a rental apartment to 78 degrees, for instance. The designer of the air conditioning system must have in mind a certain outside temperature at which the unit can keep the inside air at some certain lower temperature. I'm saying that you might expect your system to cool to 75 F when the outside temperature is 95 F. Depending on many things, you might also expect, and/or get, better performance (or worse). Maybe your system can cool to a nice comfortable 75 F when the outside temperature is 100 F. Since it can get the inside temperature to 25 F cooler than the outside temperature, you could expect it, when acting as a heat pump, to get the inside temperature to about 25 F warmer than outside. However, in very cold weather, you probably want it to get the inside to more like 50 F warmer than outdoors.
Every heat pump made has a balance point temperature. A balance point is the outdoor temperature at which a heat pump reaches its heating capacity. The heat pump will struggle to increase the indoor temperature but since the outdoor temperature matches its heating capacity, the heat pump will continue to run but have little or no impact on the indoor temperature. Most RV heat pumps traditionally will be pretty ineffective as far as providing noticeable heat when the outside air temperatures get lower than 40 degrees. On the other hand, my 5 year old heat pump here at the house has a balance point that is 21/22 degrees, and after a two degree differential between the thermostat setpoint and the inside air temperature, the electric heat strips will turn on and show on the thermostat as "emergency heat". But the purpose of my previous post was to correct your misstatement about the 20 degree differential. The differential is in reference to the the inlet and outlet air across the evaporator, not the difference between inside air temperature and outside air temperature.
