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Roof top heat pump [message #349190]

Sat, 12 October 2019 12:55

Wardhill

Messages: 63
Registered: May 2019
Location: West Baldwin, Maine

Karma: -1

Member

I have a single duo-therm roof top heat pump. It cools but no heat. Any ideas on why? Blower works fine
Thanks
Jeff

Jeffrey Fleming 1976 edgemonte Living in Maine

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Re: Roof top heat pump [message #349194 is a reply to message #349190]

Sat, 12 October 2019 14:52

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Wardhill wrote on Sat, 12 October 2019 13:55

I have a single duo-therm roof top heat pump. It cools but no heat. Any ideas on why? Blower works fine
Thanks
Jeff

Jeff,

First off, are you sure it is a Heat Pump?
Those have never been common, because the temperature band where they actually beat a resistance heater is so small.

If it cools but does not heat, then the only problem is with the "reversing valve" or its control. Now all you need is the documentation to figure that out. One good thing is that the operating coil of the reversing valve is usually replaceable without opening the system.

Matt

Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

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Re: [GMCnet] Roof top heat pump [message #349195 is a reply to message #349190]

Sat, 12 October 2019 14:56

Dolph Santorine

Messages: 1236
Registered: April 2011
Location: Wheeling, WV

Karma: -41

Senior Member

Thermostat or the wiring.

Most likely wiring.

Dolph Santorine

DE AD0LF

Wheeling, West Virginia

1977 ex-Palm Beach TZE167V100820
Howell EFI/EBL , Reaction Arms, Manny Transmission

> On Oct 12, 2019, at 1:55 PM, Jeffrey Fleming via Gmclist wrote:
>
> I have a single duo-therm roof top heat pump. It cools but no heat. Any ideas on why? Blower works fine
> Thanks
> Jeff
> --
> Jeffrey Fleming
> 1976 edgemonte
> Living in Maine
>
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Re: Roof top heat pump [message #349208 is a reply to message #349194]

Sun, 13 October 2019 07:15

Wardhill

Messages: 63
Registered: May 2019
Location: West Baldwin, Maine

Karma: -1

Member

There are controls for heating and cooling. The manual says it does both . I'll look into you suggestion thanks for the responce

Jeffrey Fleming 1976 edgemonte Living in Maine

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Re: Roof top heat pump [message #349210 is a reply to message #349190]

Sun, 13 October 2019 08:01

jhbridges

Messages: 8412
Registered: May 2011
Location: Braselton ga

Karma: -74

Senior Member

I had one of those in the 23'. Useful to get the morning chill off but that's all, it shuts down completely at about 40 f. The function switch failed on mine, I had to replace it with two switches. It puts six positions where the A/C alone has about 3 or so, at any rate this requires smaller contacts which aren't as robust, and tend to corrode and fail.

--johnny

Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell

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Re: Roof top heat pump [message #349251 is a reply to message #349210]

Mon, 14 October 2019 08:41

Wardhill

Messages: 63
Registered: May 2019
Location: West Baldwin, Maine

Karma: -1

Member

Who can service these an hvac company?

Jeffrey Fleming 1976 edgemonte Living in Maine

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Re: Roof top heat pump [message #349252 is a reply to message #349251]

Mon, 14 October 2019 08:53

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Wardhill wrote on Mon, 14 October 2019 09:41

Who can service these an hvac company?

Jeffery,

Any good HVAC tech can, most will not. The system is so small and so charge critical that the likelihood of success is not great. For that reason alone they will try to not talk to you. If you start out by telling him that it cools, he will know that it is a valve problem and may be willing to climb up and look at it.

Good Luck

Matt

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Re: Roof top heat pump [message #349274 is a reply to message #349252]

Mon, 14 October 2019 15:38

mghamms

Messages: 466
Registered: March 2016
Location: Ware, Massachusetts

Karma: 2

Senior Member

are you sure its a heat pump.
It and most that I know of have a 120v resistance heating strip.
Yours might just need that.
If so I think I have one in my junk pile.

1977 Kingsley 455 as stock as it gets except lots of Ragusa parts

[Updated on: Mon, 14 October 2019 15:38]

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