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I am replacing a basic mercury thermostat with a honeywell…

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I am replacing a...

I am replacing a basic mercury thermostat with a honeywell digital thermostat. There are only two wires, both white, but one has a red line on it. Is that one R and the other W?

Contractor's Assistant: Thanks. Can you give me any more details about your issue?

No, just that the connectors on the old thermostat were not labeled.

Submitted: 2 years ago.Category: HVAC
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Answered in 8 minutes by:
2/3/2016
HVAC Technician: Rick, HVAC Supervisor replied 2 years ago
Rick
Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 24,595
Experience: 40+ yrs. experience as a licensed oil & gas technician.
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Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

If you only have 2 wires it's not critical which wire you connect to either R or W but I would suspect the lead with the red line would be the red/R lead.

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