How I fixed my RTH230B 'blue wire'
Hi All,
This seems like the hottest place for Honeywell RTH230B questions, so I thought I would post what worked for me after much reading on this forum and troubleshooting.
My old thermostat had five wires: read, white, yellow, green, blue
The Honeywell connections for: Rh, Rc, W, Y, G
My system: central AC (not heat pump), forced hot water heat from a boiler
My problem: after leaving the jumper installed and the blue unconnected: setting the thermostat to activate heat turned on the fan but no heat
For this particular system leaving the blue wire unconnected didn't work. Put the blue wire on the W connection (which didn't work with a white wire connected) and things started working.
Troubleshooting tip: to see which wires control what I used needle nose plyers in the terminal block to verify that connecting red-to-green makes the fan come on and that connecting red-to-yellow activates the AC compressor. I couldn't tell if the solenoid to let the hot water enter the coils was coming on, and just assumed it worked until it got cold and I needed it. The right way to do this would be to trace the wires out and see what they are connected to, but laziness prevailed.
I would not recommend this therostat for a 5-wire system.
- James B