Heat strip question

raymoe3641 · 11-15-2019, 09:14 AM

I have a 2015 Seneca 37 HJ and added heat strips to the roof units. I was under the assumption that they were plug and play installs but they are not working at all. It’s very cold outside now and they should come on. Any suggestions?

Jagiven · 11-15-2019, 09:27 AM

I installed one in my 23B AC. It was a plug and play, with a knob handle change. The strip is 1600 watts which is about 5400 BTUs, so not nearly as much heat as the furnace.

My ceramic heater heater is 1500 watts (5100 BTU). The ceramic heater feels like warm air comes out of it, the AC heater feels like cold air. The difference is the amount of air flow. The ceramic heater has very little air flow, so the air can really warm up, as it has a longer dwell time near the heating element. The AC unit has a much higher air flow rate, and the air has a short dwell time near the heat strip, so very little heat is transferred to the air, during such a short contact time, but makes up for it with volume. Which circulates throughout the unit.

Turn them on, and turn the heat setting up, and let them run for a while and see what happens. After a few minutes (maybe 5 min), I can slightly tell there is warmer air coming out, but an hour later, my unit is warmer. I have had my HTT up to 80oF when I woke up in the middle of the night, so they do work, just slowly.

I think most peoples complaints are they cannot feel the warmth like a traditional heater.

raymoe3641 · 11-15-2019, 10:00 AM

Quote:

Originally Posted by Jagiven

I installed one in my 23B AC. It was a plug and play, with a knob handle change. The strip is 1600 watts which is about 5400 BTUs, so not nearly as much heat as the furnace.

My ceramic heater heater is 1500 watts (5100 BTU). The ceramic heater feels like warm air comes out of it, the AC heater feels like cold air. The difference is the amount of air flow. The ceramic heater has very little air flow, so the air can really warm up, as it has a longer dwell time near the heating element. The AC unit has a much higher air flow rate, and the air has a short dwell time near the heat strip, so very little heat is transferred to the air, during such a short contact time, but makes up for it with volume. Which circulates throughout the unit.

Turn them on, and turn the heat setting up, and let them run for a while and see what happens. After a few minutes (maybe 5 min), I can slightly tell there is warmer air coming out, but an hour later, my unit is warmer. I have had my HTT up to 80oF when I woke up in the middle of the night, so they do work, just slowly.

I think most peoples complaints are they cannot feel the warmth like a traditional heater.

Thanks! I may be impatient waiting to see if they work. I’ll let them run a while longer. But one would think that the strips would be hot to the touch or glowing if they work. Mine are neither!!

Jagiven · 11-15-2019, 10:13 AM

Quote:

Originally Posted by raymoe3641

Thanks! I may be impatient waiting to see if they work. I’ll let them run a while longer. But one would think that the strips would be hot to the touch or glowing if they work. Mine are neither!!

Mine look like my bird bath heater, and if I have it out of the water, and place it back in I get a little momentary sizzle/steam, but that is it. I would be afraid if they glowed red hot. Honestly I have never ran my AC without the cover on, so I don't know how hot they get.

Grumpy · 11-15-2019, 11:09 AM

Quote:

Originally Posted by raymoe3641

Thanks! I may be impatient waiting to see if they work. I’ll let them run a while longer. But one would think that the strips would be hot to the touch or glowing if they work. Mine are neither!!

They will get hot. If you have the heat pumps they only come on when the heat-pump shuts off. They do not work in tandem.

raymoe3641 · 11-15-2019, 11:22 AM

Thanks Grumpy. So when you say heat pump do you mean the compressor? I noticed in extreme cold the compressor will not kick on. Is that when the heat strips take over?

Grumpy · 11-15-2019, 11:30 AM

Quote:

Originally Posted by raymoe3641

Thanks Grumpy. So when you say heat pump do you mean the compressor? I noticed in extreme cold the compressor will not kick on. Is that when the heat strips take over?

Yes, at least they are supposed to, compressor should shut down at around 40.

raymoe3641 · 11-15-2019, 11:50 AM

Thanks Grumpy!! I for one really appreciate your expertise!!

EA37TS · 11-15-2019, 12:06 PM

On the Accolade I have one AC unit (rear) without heat pump and one AC unit (front) that has the heat pump. The manual for the heat pump states it will not provide heat once the temp drops below a certain level. I believe that temp is 40 degrees, however, I will have to go out to the coach to get the manual to verify that temp. To the best of my understanding the heat pump is nothing more than an AC unit with a heat strip and a thermostat that has a heat pump option. From what I have seen the heat pumps come on 15K BTU units. I have yet to see a 13K BTU heat pump. They may be there but I haven't seen one.

I could be wrong on all of this.

raymoe3641 · 11-15-2019, 12:56 PM

If you didn’t specifically order the heat pump WITH the heat strip, it would not normally come equipped with one. You are right, the compressor should not come on below ~40 degrees. A heat pump is a unit that reverses the flow of refrigerant to heat up the interior heat exchanger to provide heat. Below 40 degrees, as Grumpy described, the compressor stops AND THEN the heat strip comes on.

Grumpy · 11-15-2019, 03:23 PM

Quote:

Originally Posted by EA37TS

To the best of my understanding the heat pump is nothing more than an AC unit with a heat strip and a thermostat that has a heat pump option. From what I have seen the heat pumps come on 15K BTU units. I have yet to see a 13K BTU heat pump. They may be there but I haven't seen one.

I could be wrong on all of this.

A heat pump is an air-conditioner that works in reverse. Theoretically you can remove heat from the air down to absolute zero but the lower the outside temp the less heat is available. Many homes have heat-pumps that operate down to 30 degrees or below however they also have a way to remove the ice from the outdoor coils which does not happen on an RV air-conditioner that is why they stop operating at around 40. The perfect system for many homes is a gas furnace with a heat-pump since most electric rates are lower in the winter and using the heat-pump (a/c in reverse) is ideal until it gets extremely cold.

Here is some info:

https://asm-air.com/heat-pump/what-t...not-effective/

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