Thermostat Upgrade

JohnDar · May 3, 2009

Following the tips on the forum, I replaced the Dometic analog thermostat with a digital Hunter today. Pretty simple job. $20 for the thermostat and $3 for the little switch at Radio Shack.

I was not connected to shore power so I figured all was cool when I disconnected the OEM thermostat. About messed my shorts when the furnace fan came on when I removed the last wire.

I didn't know it was a 12V fan. Had to disconnect the battery to shut it off. Next project will be to install a battery disconnect switch.

Mucking about in the basement again, I found the reason the outside shower would not extend past the edge of the UDC. The hose was wrapped under/around the water tank fill line. Rerouted it and now it extends to a useable distance.

One more week and the 3670 heads north to its summer home.

2010augusta · May 3, 2009

sound good. I planning to do the t-stat swap soon. glad it went well.

JohnDar · May 3, 2009

Alan, if you use the Hunter 42999B thermostat, the Radio Shack SPST Micromini toggle switch, #275-0624, is the one that fits. The package says drill a 1/4" hole, but I went a bit smaller. It works better if you remove the washers and both nuts from the switch and then install it. Use the two nuts on the outside of the thermostat case to hold it in place.

2010augusta · May 3, 2009

John, the micro-switch is for the fan speed control, right?

JohnDar · May 3, 2009

2010augusta said:
John, the micro-switch is for the fan speed control, right?

Right. Here's the instructions I followed.

http://home.roadrunner.com/~morodat/hunter_install.html

I didn't have shore power, so I didn't get to actually test the A/C fan speed selection. But just setting the temperature lower than ambient, I did get the furnace fan to activate (12V). I'll get to fully test it next week at our summer campsite.

imchud · May 4, 2009

JohnDar said:
Following the tips on the forum, I replaced the Dometic analog thermostat with a digital Hunter today. Pretty simple job. $20 for the thermostat and $3 for the little switch at Radio Shack.

I was not connected to shore power so I figured all was cool when I disconnected the OEM thermostat. About messed my shorts when the furnace fan came on when I removed the last wire. I didn't know it was a 12V fan. Had to disconnect the battery to shut it off. Next project will be to install a battery disconnect switch.

Mucking about in the basement again, I found the reason the outside shower would not extend past the edge of the UDC. The hose was wrapped under/around the water tank fill line. Rerouted it and now it extends to a useable distance.

One more week and the 3670 heads north to its summer home.

John,
I replaced my last year when mine didn't work -- the dealer replaced it with yet another one that didn't work??? So i just replaced it myself...

Where is your summer location? we put our in place a month ago in Vermillon, Oh (on the lake)...

JohnDar · May 14, 2009

imchud said:
John,
I replaced my last year when mine didn't work -- the dealer replaced it with yet another one that didn't work??? So i just replaced it myself...

Where is your summer location? we put our in place a month ago in Vermillon, Oh (on the lake)...

We're at Indian River, MI, right now. The CG sits between Burt and Mullett lakes on M-27.

I've finished changing all of the floor registers to the adjustable kind. The 4x10's from Lowe's fit with a little coaxing. Now we can regulate where the heat is flowing, instead of roasting in the bedroom and shivering in the rear of the living room. It's still dipping down into the 30's at night here. And the Hunter thermostat is working like a charm.

fhollan · May 17, 2009

Thermostat!

Those Roadrunner instructions were very easy to follow. I done mine today and it worked fine.

The only question I had is where he stated "One switch wire is soldered to the base of terminal G on the back of the circuit board."

Why solder it to the pin of the circuit board and take a chance of damaging it. Instead why not hook it directly to the G terminal on the strip of the base plate?

JohnDar · May 17, 2009

fhollan said:
Those Roadrunner instructions were very easy to follow. I done mine today and it worked fine.

The only question I had is where he stated "One switch wire is soldered to the base of terminal G on the back of the circuit board."

Why solder it to the pin of the circuit board and take a chance of damaging it. Instead why not hook it directly to the G terminal on the strip of the base plate?

DUH!!

Soldering to the pin was tricky and why didn't I think of that

ChopperBill · May 18, 2009

I didn't use the switch. Too many problems running an A/C on low speed freezing up.

katkens · May 18, 2009

retired4fun said:
I didn't use the switch. Too many problems running an A/C on low speed freezing up.

I never added one either , never ran it on low anyway.....Kenny

JohnDar · May 18, 2009

retired4fun said:
I didn't use the switch. Too many problems running an A/C on low speed freezing up.

Perhaps, but with our TT, we only ran it on low speed. Couldn't hear yourself think on high speed.

rgirouard · Jul 13, 2009

John,
When I first read this thread, there were pictures of the wiring. I just bought a Hunter yesterday and came to get the wiring pictures and they are blanked out. Do You possibly have a copy that you can email me?
thanks,

JohnDar said:
Right. Here's the instructions I followed.

JohnDar said:

Right. Here's the instructions I followed.

http://home.roadrunner.com/~morodat/hunter_install.html

I didn't have shore power, so I didn't get to actually test the A/C fan speed selection. But just setting the temperature lower than ambient, I did get the furnace fan to activate (12V). I'll get to fully test it next week at our summer campsite.

Click to expand...

cookie · Jul 13, 2009

rgirouard, try THIS.

Peace
Dave

rgirouard · Jul 13, 2009

Thanks loads, cookie.
Think that will do it.

Rog

cookie said:
rgirouard, try THIS.

Peace
Dave

mountainlovers76 · Jul 13, 2009

retired4fun said:
I didn't use the switch. Too many problems running an A/C on low speed freezing up.

I added the switch and run mine on low almost all the time due to the noise it makes on high. I have yet to have any problems with it freezing up through two hot southern summers... so far. Guess I better count my blessings.

porthole · Jul 13, 2009

Has anyone tried doing this with the switch on both A/C units? Do the smaller front units usually have two speeds?

My previous TT the A/C noise would be the one factory system I did not like about the trailer.

JohnDar · Jul 13, 2009

My guess is that the updated version at this site http://www.modmyrv.com/2008/07/14/rv-digital-thermostat replaced it somehow. The photos in this one are the actual Hunter thermostat (4299B) that's now available at WalMart. I believe the other instructions were the 4299A, which looked slightly different.

In an earlier thread about doing this mod, it was brought up that it's easier to just screw the one switch wire onto the terminal (G, I think) on the back cover, instead of soldering it to the pin on the circuit board.

Ray LeTourneau · Jul 13, 2009

For what it's worth, I put the switch on the Hunter conversion. When either the temperature or humidity at night call for A/C I run it on low. Quieter!

We also just added a bedroom A/C and it has a wall thermostat too but if we run both, it seems the location of the thermostats allows the front unit to cool the bedroom adequately but it reaches the t'stat that controls the LR unit and the LR unit shuts down before the LR is cool

. I also blocked the majority of air flow going to the BR but I still have to add a vent in the Kitchen/LR area. I have the vent but not the round tuit. Once I get that vent installed, we might have better balanced flow and have the problems solved.

SilverRhino · Jul 13, 2009

Just looked on amazon.com and found a Hunter 42996 ......looks to be the same as the 42999B....except it has a remote control. Only $13 ....... would this one work the same as the 42999B? Remote is not really needed...but.....the $13 price tag is REAL nice!!

Thermostat Upgrade

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