Roof mounted heat pumps

[Bob_Vaughn]

This is a question for heat pump owners...........does your compressor in the heat mode run longer than 2-3 minutes before it turns off?

[BarneyS]

Black, Red, White, Green.

You can purchase this adapter from Camping World to adapt to an old Dometic thermostat wiring. I left my old wiring in place and used it to connect the new thermostat to new air conditioner.
Barney

[Bob_Vaughn]

BarneyS wrote:

Bob Vaughn wrote:

Shal36 wrote:
The Atwood heater does not perform well. Fortunately, I bought the unit mainly for the AC portion. I found that the heater will not reach the temperature I want and will not keep it there, even if it’s not that cold outside.

I am convinced that there is a design flaw and Atwood will not admit it .....they will not release a wiring schematic just a block diagram which does not show what color the wires are so it is useless to try to use that to trouble shoot. For instance it shows a connector with 4 attachment points but does not show what color the wires are going in an out of this connector....

I guess I am going to be the odd man out here. My Atwood 15000 btu works well in both air conditioning and heat pump modes. The fans do do some weird things on heat mode but it does warm up our 30ft trailer quite well and will hold the temp I set after a while.

Don't know if the following wiring diagram will help you or not. It does seem to show the wire colors.
Barney

Go to the connector and tell me what color the 4 wires going into the connector and what color the 4 wires are coming out of the connector........

[BarneyS]

Bob Vaughn wrote:

Shal36 wrote:
The Atwood heater does not perform well. Fortunately, I bought the unit mainly for the AC portion. I found that the heater will not reach the temperature I want and will not keep it there, even if it’s not that cold outside.

I am convinced that there is a design flaw and Atwood will not admit it .....they will not release a wiring schematic just a block diagram which does not show what color the wires are so it is useless to try to use that to trouble shoot. For instance it shows a connector with 4 attachment points but does not show what color the wires are going in an out of this connector....

I guess I am going to be the odd man out here. My Atwood 15000 btu works well in both air conditioning and heat pump modes. The fans do do some weird things on heat mode but it does warm up our 30ft trailer quite well and will hold the temp I set after a while.

Don't know if the following wiring diagram will help you or not. It does seem to show the wire colors.
Barney

[imgoin4it]

Many folks are saying basically the same thing. Except for the 15,000 BTU Atwood acnd with heat pump every heat pump out there does a good job of heating an RV. The Atwood acnd unit is great on cooling, more air than some others, and in some cases more cooling than others. It will not however raise the heat in nearly any RV even when outside temp is at or above 45 degrees. It cycles on and off continually just like Atwood says and when some heat comes out it cycles off. I’ve talked to Atwood extensively and that is just the way it works. For heating purposes it is absolutely useless.. I trashed mine and went back to the Dometic penguin.

[doc_brown]

2naEagle wrote:
As long as the temperature is above 45 degrees my Colmeman heat pump heats the trailer with no problem. Below that I run the gas.

Same on my Class A pusher.

[Fulltimer50]

I have found on my unit(not your brand) that the new style automatic thermostats will run the fan motor on low in the heat position, which is not fast enough to move much air for heating. I had to set the manual fan position to high to get it to work better. Works better but runs all the time.

[Bob_Vaughn]

Shal36 wrote:
I’m very happy with my Atwood and it’s cooling performance. It works much better and is much quieter than the old Carrier unit I had. If I remember, the 13k BTU unit does not have a heat pump but the 15K unit does. My interest was mainly in the 15k cooling. A heat pump for mild winter nights in Florida was a bonus. Since we are once a month campers, using the furnace is not a big deal.

Yes, I would be disappointed if I bought this and really needed the heat pump to perform well.

We went to Leesburg over Thanksgiving and the heat pump cycling all night and not heating the rv drove me nuts.....The compressor runs 2-3 minutes then shuts off then the fan cycles on and off for a while then the compressor comes back on .....During the summer the A/C was great....just disappointed in the heat pump....

[Shal36]

I’m very happy with my Atwood and it’s cooling performance. It works much better and is much quieter than the old Carrier unit I had. If I remember, the 13k BTU unit does not have a heat pump but the 15K unit does. My interest was mainly in the 15k cooling. A heat pump for mild winter nights in Florida was a bonus. Since we are once a month campers, using the furnace is not a big deal.

Yes, I would be disappointed if I bought this and really needed the heat pump to perform well.

[Bob_Vaughn]

If you do not like dealing with frustration then by all means do not purchase an Atwood A/C. I have spoken to various retailers of their products and they too are frustrated trying to get help from Atwood. So do your self a favor and buy some other brand....

[Bob_Vaughn]

Shal36 wrote:
The Atwood heater does not perform well. Fortunately, I bought the unit mainly for the AC portion. I found that the heater will not reach the temperature I want and will not keep it there, even if it’s not that cold outside.

I am convinced that there is a design flaw and Atwood will not admit it .....they will not release a wiring schematic just a block diagram which does not show what color the wires are so it is useless to try to use that to trouble shoot. For instance it shows a connector with 4 attachment points but does not show what color the wires are going in an out of this connector....

[Shal36]

The Atwood heater does not perform well. Fortunately, I bought the unit mainly for the AC portion. I found that the heater will not reach the temperature I want and will not keep it there, even if it’s not that cold outside.

[Bob_Vaughn]

imgoin4it wrote:
Bob, your right about 4sensors. The one that “measures the temperature is supposed to be on the return somewhere and regardless is not on the room temperature . It acts more like it is on the supply side as when the outlet temp reaches between 100 & 105 degrees the compressor shuts off. The fan then comes on for anout 5 or seconds to “sample” the temp. Then after a few minutes the fan starts again and shortly after the compressor starts again for about 2or3 minutes.until the outlet temp gets to 100 . And that cycle repeats continually. My tech says Atwood doesn’t want to talk to him anymore. I’m reasonably sure that the unit does not work like any other, Atwood , and now dometic, which I believe bought the acnd business from Atwood, knows exactly how it works and that is not like any reasonable person would expect.

It seems like as I watch the exit temp reach 100 degrees the compressor shuts off. I wonder if I could locate this sensor and move it to the return side ? I also wonder what would happen if I took a styrofoam cup and cut it dow to cover the sensor to basically disable it would it make the pump run longer??? I would just figure out how to figure out which and where it was.....

[imgoin4it]

Bob, your right about 4sensors. The one that “measures the temperature is supposed to be on the return somewhere and regardless is not on the room temperature . It acts more like it is on the supply side as when the outlet temp reaches between 100 & 105 degrees the compressor shuts off. The fan then comes on for anout 5 or seconds to “sample” the temp. Then after a few minutes the fan starts again and shortly after the compressor starts again for about 2or3 minutes.until the outlet temp gets to 100 . And that cycle repeats continually. My tech says Atwood doesn’t want to talk to him anymore. I’m reasonably sure that the unit does not work like any other, Atwood , and now dometic, which I believe bought the acnd business from Atwood, knows exactly how it works and that is not like any reasonable person would expect.

[Bob_Vaughn]

Mr Wizzard the compressor only runs for 2-3 minutes at a time then shuts off and the evaporator fan will run for a couple of seconds at a time for about 5 minutes then the compressor will come back on but for only 2-3 minutes. Thus when it is say 50 degrees outside the heat loss is as much as the heat gain thus it will never raise the inside temp. There are 4 sensors on this system and I think one in the plenum may be prematurely shutting the compressor off before the thermostat gets a chance to be satisfied. It is an electronic thermostat so it does not have an anticipator. If it had an anticipator I could adjust that but it does not. I do not think it has a high pressure cut out because if it did it would shut it off when it was in the A/C mode. I have asked Atwood for a wiring schematic but they say one does not exist. Which I think is BS.......A/C tech's would not be able to repair them with out one.....That may be why the repair place that installed it could not fix it.....