Mach 8 - Adding heat strip

[frival]

Hi all,

As we all know, living in the Northeast we have a lot of cool/cold nights. As the View only has 10 gallons of usable LP on board it would be nice to leverage a campground's electricity to heat our unit.

Has anyone thought about adding a 'heat strip' to their Coleman Mach 8 heat pump? Our 24G has one and the standard Suburban LP hot air furnace controlled with a RVComfort.HP thermostat. Question is, when the thermostat is in 'Elec Heat' mode, how does the system know to use the HP or heat strip or furnace and would it be an effective addition?

Any thoughts, experiences or even documentation (the lack of documentation is remarkable) are welcome.

Thanks to all and have a great day.

[Diesel-Lover]

Not knowing the exact details I can provide a high level how it works type answer. If the thermostat is smart and all of a sudden on a cold night you move the temp from say 55 to 75 or 80 both systems would try their best to hurry up and deliver what you asked for. However heatpumps have their limitations unless they were specifically designed for ultra cold weather (which I doubt), so if its bitter cold below the temps that the heat pump works well if at all just the strip comes on and does its best. Many heat pumps also use the strip to deice etc via reverse airflow. Generally when the heat strip kicks on one can smell the dust burning off the surface. We generally stop using the heat pumps at about 40 when we are in the rig, the furnace is comparatively a whole lot quieter and the air warmer. Plus the basement gets its heat from our furnace and the metal and glass vented glass light fixtures I installed down there with low wattage bulbs.

[Old Crows]

Obviously, using shore power is the hot tip when heating/cooling your RV. IIRC, Coleman HPs will work down to about upper 30s F. They will auto change to the propane furnace when they can't produce enough heat output to match the demand. They will also auto change if they become restricted due to frost build up in the unit. In the first case it would take a PhD dissertation to explain the algorithm driving the unit's logic and ability to determine when it will return back to the heat pump mode....but eventually it will.

A Crow's opine as to why it doesn't have a heat strip is that the coach/HP is not wired to handle both the compressor load AND the heat strip power demand. Also someone is sure to try to run the HP and heat strip off the generator. So, reaching out to the furnace for support makes a lot more sense. And it has a lot of BTUs...

In our experience, you can use a small ceramic cube heater (1600W) to adequately heat our View down to the low 30's. And, being separate from the HP/furnace you could put the thermostat on "gas" and setting the thermostat low, use the furnace as a booster if the cube heater can't maintain your comfort level. Clever and cheaper solution.

Cube heater is also was way quieter!

[frival]

Thanks for the reinforcement of what I thought we were looking at. I did go ahead and install the heater element into the AC system and it does seem to work as expected.

We also use an electric heater (way more quiet) to assist in the load as the heat loss in the View is pretty heavy, especially on a breezy day.

Also, needed to replace the 1472D5041 condenser (outside) fan blade! While it was the newer model, series "D", it would vibrate and cause noise, especially when it would cycle off.

Thanks again and many happy days ahead.

-frival