UPDATE and Boiler Question - Upgrade from Ritetemp 6022 to Honeywell RTH8560D

jonluis

Hello all, thank you taking the time to read this discussion.

I have an older Ritetemp 6022 thermostat and I tried to upgrade it to Honeywell RTH8560D.

This is a single family home with a gas steam boiler with cast iron radiators.

Behind the thermostat are black, white, red and green wires.

The Ritetemp 6022 was connected as follows:

Black connects to B

White connects to W

Red connects to RH

Green connects to G

The jumpers 4 and 5 are active as well.

The Honeywell RTH8560D was connected as follows:

Black connects to O/B

White connects to W

Red connects to R with the switch in the up position

Green connects to G

I installed batteries and began to program the new thermostat.

Once I plugged in the thermostat to the mount, the boiler turned on even though ambient temperature was above the set temperature.

Using the thermostat, I set the mode to Off but the boiler continued to run. Once I removed the thermostat from the mount, the boiler turned off.

I called Residio and they said the thermostat works and the issue is with my boiler wiring.

I have a multimeter if anyone would like me to try something.

Your help and guidance is greatly appreciated!!!

Thank you!

jonluis

Maybe my Black wire is really a C-wire?

Jamie Hall

jonluis said:

Maybe my Black wire is really a C-wire?

That would be my first guess... you have a multimeter? OK. With the thermostat disconnected, look for a wire with a random voltage -- or 0 on it. That's your W. Then look find a wire which, when crossed with that one makes the boiler turn on. That's your Rh. That wire should then be 24 VAC more or less to one other wire -- and that third one is your common.

jonluis

Jamie Hall said:

Maybe my Black wire is really a C-wire?

That would be my first guess... you have a multimeter? OK. With the thermostat disconnected, look for a wire with a random voltage -- or 0 on it. That's your W. Then look find a wire which, when crossed with that one makes the boiler turn on. That's your Rh. That wire should then be 24 VAC more or less to one other wire -- and that third one is your common.

I do have a multimeter.

All four wires do not have anything printed on them. They are just plain colored wires.

jonluis

jonluis said:

Maybe my Black wire is really a C-wire?

Using my original Ritetemp thermostat, I connected the Black wire to the C location and removed the 2 AAA batteries. The thermostat shut off so I guess that isn't a C-wire.

jonluis

Just to clarify, this is a natural gas steam boiler with no heat pumps and just cast iron radiators throughout the home.

Do I need to connect the green wire?

From further reading, green is indoor fan.

Thanks!

jonluis

Update...

I tested various pairs using a multimeter.

Black and White yielded 27ish volts. All other combinations were under 8 volts.

I crossed Black and White and the boiler turned on.

Using the old thermostat, I connected only Black and White and the boiler ran normally. It worked according to schedule with no issues.

I connected Black and White to the new Honeywell and the boiler kicked on right away. It would not shut off when I turned the thermostat mode to off. I then connected Black to the thermostat's Red and the thermostat works as should.

My one complaint with the new thermostat is there doesn't seem to be a temperature swing setting. With my old, if I had it set to 69, the boiler would kick on at 67 and shut off at 71.

With the new Honeywell, it seems to kick on more frequently to maintain 69. I have adjusted the CPH for heat to 1. I cannot find a swing setting nor do I think one is available.

With a gas steam radiator boiler, is there any harm in it running more frequently?

Thanks for everyone's advice and I look forward to your thoughts on the frequency of the boiler running.