# new honeywell rth6300b to replace very old honeywell thermostat



## Designman20 (May 6, 2007)

i have purchased a new honeywell thermostat (rth6300b) to replace an old honeywell thermostat. the only 2 wires from the old thermostat are RED and BLACK with no letter designation anywhere. i only have a heating system with no cooling, the heating system i have is a hot water system with radiators, a gas boiler with a pump. First of all, to help me better understand, what type of heating system do i have? where does the red and black wire go to on the new honeywell digital programmable thermostat? the possible slots on the new honeywell are as follows

G - W(O/B) - NOT USED - Y - R - Rc 

I apprciate all your help!

Designman20


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## MayDix2009 (May 6, 2009)

You mean the thermostat that you have purchased, a new honeywell thermostat (rth6300b) to replace an old honeywell thermostat... How is the difference??



_________________
Programmable Thermostats


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## beenthere (Oct 11, 2008)

If the new thermostat is battery operated.
R and W.

If it needs power from the boiler, wrong thermostat.
Or you will need to run more wires.

You have a hot water boiler system.


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