[Bmartin]

I am installing a Honeywell RTH230B thermostat but am not sure of the wiring. I have 6 wires colored as follows, red, green, white, yellow, and 2 blue wires.

Please advise?

[labman]

You will need to check the heating system and identify the function of the blue wires. If one isn't connected, likely the other is the common, C. If you have a heat pump, the second blue wire may be part of switching modes. Otherwise follow the standard connections.

Usually there is a 24 volt AC transformer in the furnace with the secondary winding connected to a red wire running to the thermostat and a blue wire, common, to the gas valve, A/C relay, and fan relay. From the thermostat there will be white wire to the gas valve, yellow to the A/C, and green to the fan. The thermostat is wired to switch the power from the red to the white, yellow, and green as needed with the blue completing the circuit. Most thermostats and furnaces have the contacts labeled R, B or C, W, Y, and G for the corresponding wire colors. It may be wired to have the A/C control wires return to the furnace and its controls and then a second wire goes to the A/C unit. Internal wiring may replace the green wire if the thermostat does not give you the option of fan only or continuous fan. Digital or programmable thermostats may need the blue wire connected to them.

Jumper the red wire to RC and RH. If you do a search, you will find the RTH230B a troublesome unit I haven't been very successful with helping people. Some people have found they need to change batteries and select the correct operation. I hope you have the directions in English. There are people here that can give much better advice than this in some other areas. I am doing what I can here until somebody better comes along.

[Bmartin]

Thanks... I'll have a look... If it helps, I'm replacing a RobertShaw 9420.

[labman]

Did you note what the blue wires were connected to if anything before?

[Bmartin]

The labels are Y2, Y1, E, W2, G, O, B... iin addition to L, C, R... The connections were:

Red- R
Blue- C
Yellow- Y1
Green- G
White- W2
Blue- B

The problem is the RobertShaw thermostat was working perfectly until about a month ago, then it started clicking off altogether (no reading or anything) and would be "dead" for about a day or two then come back alive.

It would only come back alive after I've had the switch turned off for a few hours, (sometimes 24 or more).

[Bison]

Just a note about the Honeywell RTH230B (It appears this thermostat has some notoriety around here). I recently replaced and installed this thermostat from a non-programmable Honeywell I had. My HVAC system is as follows: gas fired furnace with an outdoor A/C unit. The existing wiring was five wires routed from a low voltage panel (located in the indoor gas fired furnace) to the new thermostat like below:
Rh - red wire
Rc - Blue wire
W - White wire
Y - Yellow wire
G - Green wire

So, each wire I connected to an independent connection on the back of the new prog thermostat. In addition, from the outdoor A/C unit, I have two wires routed to the low voltage panel in the furnace. They share connections with wires from the tstat on the "C" & "Y" connection on the low voltage panel.

This setup worked great (for the heating season, anyway) until the cooling season arrived today. This made sense to me at the time - 5 wires, 5 points of connection. Done, right. Little did I know.

My girlfriend came to me this morning and said she had turned the tstat to cool, but the outdoor unit nor the indoor blower engaged. So, I started my investigation.

Turns out even though I have 5 wires from the low voltage panel routed up to my thermostat, the Blue (Rc) wire, however, was not to be used from the low voltage panel (through trial and error and lot of reading today) . Instead, I placed a jumper connection between the "Rh" and the "Rc" connection at the tstat and kept the red wire hooked up (at the "Rh" connection), along with the remaining 3 wires (this is a 4-wire configuration). I based this on the manual from the Honeywell RTH230B thermostat. You may know there are various methods (5-wire , 4-wire etc) for connection.

Now, my cooling system works fine and my heating does too.

I hope this may help someone in the future, because I know by reading here today helped me a great deal too.

Just want to share.

Thanks,
B

[jss27560]

I seem to be having a similar problem. The house is a dual zone system and the upstairs is working fine. The down stares is where the problem is. It is also where the RHT230B is installed. The heat worked fine but switching to the AC doesn't. I seem to bet getting air blowing thought the vents but it doesn't seem cool. There are 4 wires going to the tstat and they are connected to the corresponding spots on the tstat.

The outside unit is a Trane 'Gas Pack'. Not sure what exactly a gas pack is unless it is another name for the heater/AC unit. I tried moving the jumper from HE to HJ but it seems to only cause the air to blow harder from the vents. But when I checked the tstat it the blower has stopped.

The house is a rental so I don't know everything about the heating/cooling system. I know there is something in the attic but I'm unable to check it right now.

I'm going to call the landlord tomorrow and have then take a look at it tomorrow but it's 80 deg down stares and that is hot.

Jeff