Question about Honeywell Programmable Thermostat Heater

1 Answer

Honeywell RTH 230B Thermostat Wiring

Help!!!!!! I bought the above programmable thermostat to replace an old HW mercury thermostat. I thought it would be an easy switch..wrong!

I have an oil-fired furnace - heat only - no A/C units. On tactual furnace, there is a White wire and Blue wire connected to each of two "Thermostat" terminals (both unmarked)

The old mercury thermostat I removed was connected by two wires (blue to one unmarked terminal and white to the other unmarked terminal). There was a red wire loose and unconnected/unstripped.

I installed the HW prog. thermostat.

On the new one the connections are Rh Rc (jumpered) W Y G.

Following the instructions for 2 wire installation (I assumed since the old once was hooked with two wires, the new one was also a 2-wire installation), I removed the jumper from Rh/Rc. (correct??)

Since there were no wiring instructions with the Thermostat (duh??!) I guessed and connected them as follows:

Blue to RH
White to W

Left the red hanging as per the original.

The ambient room temp was 76 degrees. When I change the set point to 82 and switch to "heat" to test the furnace, nothing happens.

I've tried the wires in a few diferent spots but nothing!!

do I have to now use the red wire in the new thermostat??
should I have removed the jumper?? (I have a second unit with jumper intact if need to use it).

Can anyone tell me how to connect it using the colored wires I have before I jump off a cliff!!

Thank you so much in advance,


Posted by on

  • keywest508 Nov 14, 2008

    Somewhat the same. I hooked the red to the area for the red and white to the terminal for white and removed the jumper. Increased temp above room temp, boiler started for about 60 secs and turned off. Any thoughts ?


1 Answer

  • Level 1:

    An expert who has achieved level 1.


    An expert who has answered 20 questions.


    An expert that hasĀ over 10 points.


    An expert whose answer gotĀ voted for 2 times.

  • Contributor
  • 24 Answers

Put the jumper back in RC and RH and that should do it.

Posted on Apr 15, 2009

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

I installed the RTH 230B thermostat, Theheat only works when set to the cool mode, I only have gas furnace(no ac unit). My old wires are Red, white, green and blue. What wires go where?

Hey jim Try....RH/RC jumper (connected with a small piece of wire)...RH/RC=RED...W=WHITE...G=GREEN blue=unused... should give heat only (in heat mode) no ac..tks

Nov 12, 2011 | Honeywell Programmable Thermostat Heater

1 Answer


Electronic thermostats are powered by battery or off of the 24 volt power from the furnace or air handle, or by both. Check and make sure that you have 24 volts from the furnace. If you do have power, then you have a bad thermostat, it make have just gone bad, or got shorted out.
Drop me a line, with more info and I will be happy to help.
Have a great Evening!
Paul Gibson

Apr 08, 2010 | Honeywell Programmable Thermostat Heater

1 Answer

Model # RTH 1108 stopped displaying the

is my thermostat( honeywell rth1108) somehow to my attic fan. cant find a off switch for the fan. seems it is controlled by the thermostat.

Nov 29, 2009 | Honeywell Programmable Thermostat Heater

1 Answer

Honeywell RTH 221 Programmable Thermostat. Jumper missing

The proper way to do it would be to use a small piece of wire stripped at the ends. Then use a small amount fo solder on each end to connect RC to RH. Or use a small piece of solid(stiff) wire and strip the ends. The wrap the ends around the connector and crimp them to make contact. I would not use a paper clip. A paper clip is not designed to carry 24volt current and could melt.

Nov 02, 2009 | Honeywell Programmable Thermostat Heater

1 Answer

Non programmable Honeywell to programmable

the 230 doesnt sound compatable with your system. you are gonna need a t stat that is compatable with Heat Pumps.

Mar 18, 2009 | Honeywell Programmable Thermostat Heater

1 Answer

Wc wiring on thermostat

sounds like you have a heat pump the w2 on old thermostat is for a second stage heat. If you can give me a little more information on type of system you have (forced air furnace with heat/cool, Heat pump or boiler)? How many wires are on old thermostat? Is it a no programmable or programmable? How old is the furnace?

Jan 17, 2009 | Honeywell Programmable Thermostat Heater

1 Answer

Y1 W1 Wire from older Honeywell to new RTH honeywell

Y1 means for cool and W1 means for heat. Connect accordingly.

Aug 11, 2008 | Honeywell Programmable Thermostat Heater

1 Answer

Digtal thermostates

Give this number a call if you are in the US, 800-341-0110. You will need the COMPLETE model number not just 230B. Something like YRTH230B1009. They can link you a manual via email.

Nov 13, 2007 | Honeywell Programmable Thermostat Heater

Not finding what you are looking for?
Thermostats Logo

1,286 people viewed this question

Ask a Question

Usually answered in minutes!

Top Honeywell Thermostats Experts

Bill Long

Level 3 Expert

577 Answers


Level 3 Expert

1875 Answers

Brandon Berry
Brandon Berry

Level 2 Expert

407 Answers

Are you a Honeywell Thermostat Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides