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BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22102
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I am replacing a Honeywell Thermostat T87F with a Honeywell

Resolved Question:

I am replacing a Honeywell Thermostat T87F with a Honeywell RTH221B Programmable Thermostat and I did not mark the wires on the old thermostat. I have taken off the old but I can not make the correct connections with the new because I don't know where the wires connect to. I should have read the directions fully, what a dummy. Can you help me?
Submitted: 6 years ago.
Category: HVAC
Expert:  BillyHvac replied 6 years ago.
Chat Conversation Started
Billy :

Hello....were all 5 hooked up on old stat?

Customer:

No , I removed the wires before I noticed the letter codes on the old thermostat.

Customer:

Did I send you the right info

Billy :

Ok...so were 4 wires hooked up?

Billy :

I just need to know how many you think you took lose...

Customer:

5 wires hooked up initially. I then removed all 5 wires and now need help with connecting those wires to the new stat.

Billy :

Thank you....what do you have for heatng cooling equipment? Then there is a test to find wout what goes where

Customer:

I have an oil fired heating system and Bryant AC cooling system

Billy :

Ok....2 wire = red to rh and white to W. 3 wire = red to Rc, green to G and white to Y

Billy :

Make sure you remove jumper between rc and rh

Customer:

I wired it as suggested and it works! Thank you so much.

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