Question for Carrier AirV HP owners...

[TCM1]

I installed a new Carrier AirV HP two weeks ago and am curious how much heat is normal when in heat mode and the unit is using the heat strip feature. It's been cold here, down to 7°F one morning, but even when it warmed up to the low 30's there was very little heat. I understand how the heat pump works and that below freezing the heat strip will be energized to provide heat, but mine puts out so little heat the heat strip feature is practically worthless. I live part-time in my AS and was hoping to rely on the AirV as a backup heat source at times. I haven't been in the camper with the temps above 32° since I installed the new AC, so I don't know how the unit will work above freezing.
Thanks, TCM

[olddog299]

My unit puts out next to nothing below 40°F or so. Currently seeing exterior temps in a range of -2° low to 35° high. I have access to a full hook-up right now and am using two 1500 watt electric heaters to maintain liveable temperatures, with a 9000 BTU catalytic LP heater for a quick boost in the AM and whenever the temperature falls below 10° F. (My LP furnace is shot with no money to replace at the moment.)

It worked fine last year down to 40° or so. Below that, I didn't bother, relying on the LP heater (and the bloody condensation). I'd have to go back and read the manufacturer's literature, but I don't think they ever really expected it to work at below-freezing temperatures.

As I recall, delivery of heat takes about 15 minutes for the full reverse cycle to be established and the temperature differential to be great enough that the refrigerant condenses. Until it reaches that point, cold air is blown. To be sure that the heating cycle is operating properly, allow it to reach temperature and then measure the amp. draw of the unit - it should be 13.8 amps at 110 VAC. I'd also check the amperage draw of the heat strip and the continuity of the strip. While not fragile, they can be damaged and most installers haven't a clue nor care - so long as they see an increase in temperature after 15 minutes of operation, it "functions within normal parameters." (I have never seen an installer actually test the heat strip function with freon - too expensive and EPA rules have probably made that a thing of the past).

[Boondocker]

The Carrier heat strip is nothing more than a small heating element. It is not intended to heat the camper alone in cold weather. It adds a small amount of heat and takes some load off the furnace. Even though the air feels cool coming out of the unit, it is warmer than going in. My trailer uses noticeably less propane when I use mine. When the weather is in the 40s and above, very little if any other heating is needed.

The strip is pretty good for what it is, just dont expect it to be what it is not.

[lewster]

Originally Posted by olddog299

My unit puts out next to nothing below 40°F or so. Currently seeing exterior temps in a range of -2° low to 35° high. I have access to a full hook-up right now and am using two 1500 watt electric heaters to maintain liveable temperatures, with a 9000 BTU catalytic LP heater for a quick boost in the AM and whenever the temperature falls below 10° F. (My LP furnace is shot with no money to replace at the moment.)

It worked fine last year down to 40° or so. Below that, I didn't bother, relying on the LP heater (and the bloody condensation). I'd have to go back and read the manufacturer's literature, but I don't think they ever really expected it to work at below-freezing temperatures.

As I recall, delivery of heat takes about 15 minutes for the full reverse cycle to be established and the temperature differential to be great enough that the refrigerant condenses. Until it reaches that point, cold air is blown. To be sure that the heating cycle is operating properly, allow it to reach temperature and then measure the amp. draw of the unit - it should be 13.8 amps at 110 VAC. I'd also check the amperage draw of the heat strip and the continuity of the strip. While not fragile, they can be damaged and most installers haven't a clue nor care - so long as they see an increase in temperature after 15 minutes of operation, it "functions within normal parameters." (I have never seen an installer actually test the heat strip function with freon - too expensive and EPA rules have probably made that a thing of the past).

Are you talking about a heat strip or a heat pump? One is nothing more than a 500 watt heating element stuck into the incoming air stream of your A/C unit while the other utilizes the compressor and with a reversing valve, changes the direction of the refrigerant flow to have the normal evaporator function and a condenser, thus creating the heated air stream into the coach. They do not work well below 40*F, if at all.

Heat strips will only take a bit of chill out of the ambient air and were never designed to replace the function of your LP furnace.

[vswingfield]

The heat pump Carrier Air V units (the nonducted ones) have a heat strip that they switch to when the temps get too low for the heat pump to work.

When it warms up into the mid 30s, mine works very well. When it switches to the heat strip it helps a little, but there is a noticeable lessening of heat output. When it drops to those levels, though, it is time for some furnace heat to keep the plumbing and tanks from freezing anyway.

Glad that it has only dropped into the 20s for a few hours in the middle of the night a couple of times here in Little Rock so far.

[olddog299]

Originally Posted by lewster

Are you talking about a heat strip or a heat pump? One is nothing more than a 500 watt heating element stuck into the incoming air stream of your A/C unit while the other utilizes the compressor and with a reversing valve, changes the direction of the refrigerant flow to have the normal evaporator function and a condenser, thus creating the heated air stream into the coach. They do not work well below 40*F, if at all.

Heat strips will only take a bit of chill out of the ambient air and were never designed to replace the function of your LP furnace.

Hi Lew, nice to see you about. Exactly what I was saying about the heat pump with the heat strip activated - a max electrical draw of 13.8 amps, according to the manufacturer's manual. No possibility of heat below the freezing point, to speak of (a 500 watt heater is merely blowing into the wind = not very effective). However, above 40°F or so, outside, the heat pump (alone) works nicely and proved to be adequate for most of the heating needs down in Louisiana last winter, for instance. It just couldn't handle the dozen or so nights when the temperature dropped colder. Then we used our electric heaters.

I hope that is clearer. Thanks for pointing out the possible confusion I'd created in my reply to TCM.

[lewster]

Wil,

You can probably tell that I don't work on Carrier units (by choice!). I usually have at least one project going to switch out a defunct Carrier unit for either a Dometic or RVP unit. I had a very bad experience with Carrier a long time ago related to their warranty/payment policies and tech support (actually, their LACK of tech support) and I have never sold or serviced their units since. It's all moot at this point, although I hear that they have committed to having repair parts available for 10 years or so.

Anyway, I have found that if you have sufficient electricity available to power a roof A/C-heatpump, it is often more cost effective and efficient (thermally speaking) to use either a ceramic disc furnace or thermostatically controlled oil-filled radiator to satisfy your heating needs.

Just an observation.

[TCM1]

Question answered. I appreciate all the replies. The unit seems to be working correctly. When I first installed it, there was absolutely no heat. I contacted Carrier and was guided to a manual reset button on the heater assy. I reset and it began working, but I was surprised at the small amount of heat it was putting out and wondered if it working correctly. TCM

[blickcd]

I've been satisfied with my Air V HP and the heat strip coming on when it is too cold for the compressor to run. However, I'm done camping for the year when it drops below freezing outside.

Christopher