I purchased a Honeywell digital t-stat RTH2410B. I have looked at a video posted here on installing a new controller. The problem is, in the video he only has 5 wires, red, yellow, white, green, gray. I have those wires plus a light blue wire. And according to the owners manual and installation instructions in the motor home, that wire is a 12V- wire. where do I hook it up at? The back of the new controller has B,O,G,Y,W/AUX,NOT USED,R AND Rc. R and Rc has a jumper across them from factory. I have red hooked to R ,yellow to Y, w to white, grey and green are the fan speed.

If your new one is for residential use, it probably won't work in the RV.Residential models work on 24V AC/DC from the furnace controller.RV units work off the 12 V supply.

Sam Spade wrote:If your new one is for residential use, it probably won't work in the RV.Residential models work on 24V AC/DC from the furnace controller.RV units work off the 12 V supply.Yea, that's what Shawn from India said when I called the 1-800#. But they will work off 12v. Did some searching on the web, found out you do not hook the blue ground wire up. But still could not get anything to work. Did some reading, tried hooking the red hot wire to the blower motor wire, nothing, tried the heat and a/c nothing, could hear relays clicking but nothing worked. Happened to look up at my volt meter plugged into an outlet and noticed it was on 0. Plugged the shore power in, and now everything works perfect. LOL.

It's a Beautiful Thing! Congratulations! Really, no kiddin', many won't even consider taking that wonderful upgrade on as DIY.

j-d wrote:It's a Beautiful Thing! Congratulations! Really, no kiddin', many won't even consider taking that wonderful upgrade on as DIY.Had it not been for not hooking up the shore power, I would of been done in 2 hours or less. It is an easy, cheap upgrade.

Yes you need shore power for th A/C Unit to work but furnace should work directly from battery Many 'residential digital t-stats' can be used in an RV.Hunter, Honeywell, LUX are just a few.Depending on how RV A/C-Furnace controls are set up some don't use the 'Blue Wire' (12V -) and some don't use the 'Red Wire' (12V +)Wires not used should be taped off and safely tucked inside t-stat panel (don't lose them back inside wall---might need in future)A/C Fan wiring-----you can install a mini toggle switch to switch speeds from high to low, some can be wired just with Hi Speed wire or LO speed wire, some need both wires connected in order for just HI Speed.But residential t-stats can be used in RVs------just need to use ones that operate the display using AA batteries

installing digital t-stat help needed | Good Sam Community

dieseltruckdriv
Explorer II
Apr 01, 2016
kwplot34 wrote:
I am using the option for the 5 min delay on compressor start up, seems like a safe move. you can turn that feature off. I did not install a switch so I can have low or high fan speeds, wired it so its on high all the time with the green wire. The grey wire for low is taped up so if I decide to install the switch later its right behind the t-stat.
I have been using a Honeywell smart thermostat for several years now. I wired mine up only using the high AC fan speed like you did, and have never felt a need to hook up the switch for the low speed. But I wasn't sure at the time, so the option is there.
kwplot34
Explorer
Apr 01, 2016
Sam Spade wrote:
kwplot34 wrote:
Plugged the shore power in, and now everything works perfect. LOL.

Maybe not.

Having the AC power on will give you the 24V from the furnace/AC controller board probably.

If your heat is supposed to work when on battery power only, that might NOT work still.

(Oops. I see this has been answered already.)

Yea, with the shore power disconnected, the gen set off, just the coach batteries connected the heater still works.
Old-Biscuit
Explorer III
Apr 01, 2016
kwplot34 wrote:
Sam Spade wrote:
kwplot34 wrote:
Plugged the shore power in, and now everything works perfect. LOL.

Maybe not.

Having the AC power on will give you the 24V from the furnace/AC controller board probably.

If your heat is supposed to work when on battery power only, that might NOT work still.

(Oops. I see this has been answered already.)

Yea, with the shore power disconnected, the gen set off, just the coach batteries connected the heater still works.

And there is NO 24V DC ......it is 12V DC from battery or converter which is used by the residential t-stat.

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