Houghton AC-installing a Honeywell PRO 1000 Thermostat

[Nan]

Can someone please tell me how to wire the Honeywell PRO 1000 Thermostat (Heat Only) to the Houghton Air Conditioner?  I opened a ticket with Mike Sharpe and he could not get me the information even though the service department had just wired the Dooley's Oliver the week before. I am all set to install the new AC, but need information on the wiring.  Thanks so much everyone!

[Nan]

OK, still not able to get the Honeywell Pro 1000 to turn on the heat, but the Houghton AC and heater strip are working just fine. It is so much quieter.

 

[jd1923]

Sorry I did not notice this a month ago... I and others would have read your post sooner if it was listed under Campers and Ollie Modifications. Houghton and Honeywell being mods. Also, many would not know the answer.

Thermostat cables generally have 5-6 wires, and each one has a designation. I have a whole spool of 6-wire thermostat cable. One colored wire is for fan, furnace, A/C, heat strip, etc. You need to find the wiring diagrams for both products, the Houghton and then the Honeywell. 

[katanapilot]

It's hard to provide an answer to this question not knowing how you connected the Honeywell thermostat to the existing wiring and whether or not you kept the Dometic control relay box in place.  Lots of good info in previous posts - maybe start with the "Got Earplugs" thread I started a long time ago.  Many users have posted how they converted to the Houghton from the noisy Dometic.

In my case, I only use the remote control for the Houghton heat pump and still use the factory Dometic thermostat and control box to run the Suburban furnace.  As I recall, the factory wiring from the thermostat to the relay box may have been digital, so there weren't enough wires to convert to a more traditional analog wiring scheme for both the Houghton and the Suburban.  I also don't think there was any way to connect to the Houghton with an external thermostat (at least the model I used). 

[Nan]

I cannot find the "Got Earplugs" thread. I really need to figure this out.  Thank you so much.

[jd1923]

Just searched for keyword "earplugs" one word and this came up: 

 

[SeaDawg]

Nan, we have an old school separate thermostat for the furnace. The Houghton runs off the remote supplied with it.

[Geronimo John]

Nan:

When upgrading from the Dometic to Houghton A/C, the digital Dometic T-stat cannot easily be used.  As such, the Suburban Heater will require a means to turn on/off and modulate temperature.  An easy way to do this is to install a Heat Only T-stat.  Several owners have used this process and it works.  Most importantly you don’t need to be fishing wires thru the hull to do so.

Heat only T-stats typically have 4 terminals.  They have a temperature sensing element that opens or closes based upon temp for the heater.    This “switch” is connected to two of the terminals.  The onboard batteries of the T-stat powers its lights and control board.  Two are needed for the Heat Only function. For the heat side of the T-stat you will need a power in (all the time) and a power out only when you have switched the T-stat on and it is below your set point.

In most of our OTT's, the power in (+) is provide by the furnace which has a transformer for its controls.  They have tapped the + side and sent them “TO” and “BACK from the Dometic via a pair of wires between the hulls up the curb side, over the roof to the A/C 14” X 14” roof penetration.  To mount the Houghton, you disconnected them where they enter this roof penetration.   The Dometic also uses the 12V + from the heater transformer to operate.    

The Dometic communicates with their transformer digitally.  It uses a four-wire cable with very small wires from their onboard circuit board to its digital T-stat.  It has four wires as I recall and with them it controls fan speed, mode (AC/Heat/Fan) and temp control. But these 4 wires individually are too small to carry the load from the heater all the way to the Dometic T-stat location AND back to the furnace. BUT...

If you double up the four small Dometic digital wires into two each two pair they make circuit that will control the furnace when the T-state says to do so.  So, that's how it works.  Now you just need to connect the paired wires to the new thermostat.  For that see the next post: 

 

 

Edited June 23 by Geronimo John
typo

[Geronimo John]

Follow-up:

For your Honeywell 1000 Pro:  hook up the two sets to the Red and White terminals:

 

For the Emerson Heat Only you remove the jumper wire and use the W and the RH terminals.  Connect one set of two wires to each.  Done.

 

Edited June 22 by Geronimo John
Added pictures