Installing LCD Thermostat

[munsonjl629]

I have a 1998 Sandpiper 5th wheel. My Duo-Thermostat is 25 degrees off on regulating the temperature. I went to local RV dealership to get a new thermostat and they sold me a Dometic LCD 3313195.000. My 5th wheel currently has 6 wires and the new thermostat has 3 posts. I asked how to wire this up and they told me to hook ANY three wires up and leave the others. I am very skeptical. Has anyone heard of this? Any one know how I would wire the new thermostat. My 5th wheel has wires for (heat, AC, fan, fan hi, ground, power). New thermostat has (12-, comms, 12+).

 

[docj]

I also have an older Dometic A/C and looked into installation of that same thermostat.  My understanding is that it cannot be directly used on the older units without changing the controller and associated wiring.  I did confirm that online, but I can't find the link that finally convinced me it wouldn't work on my system.

 

[Kamper Dave]

No. I do not but maybe Klenger can help you.
http://www.klenger.net/RVing/HVAC_Hunter_Tstat/hunter-digital-tstat-instructions.pdf

 

[Alfa38User]

Personally, I would return the Dometic thermostat to the seller as unsuitable because of the other mods required and search out an appropriate Hunter brand. There is a wealth of info available on the install of a Hunter brand as evidenced by the link shown in the previous message. That one is one of the most detailed I have seen to date......

 

[denmarc]

I have to agree with Stu.  I replaced the t-stat in my 1994 Jayco 3-4 years ago with a Hunter from Walmart.  $18.00 if I recall.  The only thing I lost was the low fan speed (my choice of low or high).  Otherwise, it works great.  Two AA batteries last me all season (Spring into December).  A ton of info available to make the changeover. 

If you are handy and can follow directions, then you would have very little problem doing the same conversion.  And I am guessing you paid the long dollar buying from a dealership parts dept.  Get your money back for the new t-stat (I'm thinking you got the wrong one anyhow.) and get the Hunter that will work for your application. 

 

[Ghostman]

You can do as he suggested an by a home thermostat form any where. The only difference is the high low switch. I added a high low switch into my control center separate form the thermostat. There I can switch the fan from high to low.

 

[Icemaker]

I have to agree with Stu.  I replaced the t-stat in my 1994 Jayco 3-4 years ago with a Hunter from Walmart.  $18.00 if I recall.  The only thing I lost was the low fan speed (my choice of low or high).  Otherwise, it works great.  Two AA batteries last me all season (Spring into December).  A ton of info available to make the changeover. 

If you are handy and can follow directions, then you would have very little problem doing the same conversion.  And I am guessing you paid the long dollar buying from a dealership parts dept.  Get your money back for the new t-stat (I'm thinking you got the wrong one anyhow.) and get the Hunter that will work for your application.

This may work for you ;

I replaced my t'stats, 94 Dolphin and wired the stat for a/c[Y-1] and the high speed fan [Y-2]

the first call for a/c is on low speed & if the temp raises enough to call for 2nd stage the fan goes to high speed..
I don't remember using just the fan...but think it will just bring on the fan as a high speed...again not sure..
Used it all summer on a trip and either a/c worked like a charm..

Of course the heating is a separate circuit..by it's self... it's fan is self controlled..

George

 

[denmarc]

Thanks for the info, George.  I will keep that in mind. 

If I recall, the Hunter I used was a basic digital model and I didn't have a choice to utilize high and low speed when wanted.  The t-stat wasn't wired that way.  It was one or the other.  No problem though.  We are parked in the woods of MI.  Outside all the time.  Only really use the fan only mode during the day to circulate air at times.  Fired up the A/C in the evening during those hot, humid conditions to cool down and dry things out inside for a comfortable nights sleep.  Ending a great day of cooking, eating, and reminising around the campfire with our neighbors and friends until the wee hours of the morning. 

Yes...adult beverages are involved.  But the racoons and deer don't seem to mind.  We once had a Barred Owl show us how he felt about it though. 

 

[carson]

When I installed the little Hunter I tested the hi speed versus low speed fan operation. There actually was little noticeable difference. So I wired it for low speed operation to run at a less stressing speed. This was in a 32' Class A. I also left the #2 A/C thermostat as is (The old Coleman)

 

[denmarc]

When I installed the little Hunter I tested the hi speed versus low speed fan operation. There actually was little noticeable difference.

Pertaining to voltage draw or inside comfort?

 

[carson]

Mark, my concern was inside comfort only, plenty of air on low. My theory was that the air would not be colder on fast only a little more air pushing.  My RV had rotable outlets in the ceiling so I adjusted them for best blow where ever we were usually sitting. While driving the flow over the drivers and passenger seat would freeze us to death. JMHO...

 

[denmarc]

Carson,
Works for me.  My outlets are ceiling mounted and blow 360 degrees.  Adjustable as far as volume allowed.  Your idea is the same as mine.  I just wondered if you wired it on low speed for some kind of electrical reason, as opposed to a comfort reason. 

Not a big deal for me to pull a couple of screws and change the wiring from high speed to low speed.  The first thing I need to do this coming season is check my starting caps. in my A/C unit.  Stopped working last season.  Hard start problem.

After getting that taken care of, should be good to enjoy.  Thanks.