Replacing line voltage thermostat


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Old 01-09-16, 01:39 PM
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Replacing line voltage thermostat

Hey furd I have the same setup as the other guy. I have a line voltage thermostat, but it reads 30volts when tested. So how to I hook up a low voltage thermostat? Since I only have two wires


Separated from.... http://www.doityourself.com/forum/th...baseboard.html
 

Last edited by PJmax; 01-09-16 at 02:00 PM. Reason: started new thread
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Old 01-09-16, 02:04 PM
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Welcome to the forums.

Since you've measured 30vac you have a standard switching system

Use a battery operated thermostat and connect one wire to R (leave Rh-Rc jumper) and the other wire to W.
 
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Old 01-09-16, 03:29 PM
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line voltage thermostat using 30volts

I have a oil heating system with water heated baseboards. I have two thermostats, one upstairs and down. They are both labeled high voltage, but when tested read about 30volts. They both have only two wires. How do I hook up a low voltage thermostat with only two heavy guage wires? Thanks in advance!
 
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Old 01-09-16, 04:16 PM
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You don't state why you want to change the thermostats. I would consider 30 vac across the two wires going to a thermostat (not calling for heat) to indicate a 24 vac control circuit. Can you be more specific about the size of the heavy gage wires that are installed? Also, why do you think two wires at the thermostat are not sufficient? A thermostat is only a switch and does not need a common wire unless other functions are being controlled by the thermostat.
 
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Old 01-09-16, 05:12 PM
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@PJmax Thanks for combing my threads, I didn't realize I had two. I will give that a try. I was under the impression a low volt system wouldnt program with two wires.
 
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Old 01-09-16, 05:15 PM
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There are many stats you can get that will work with only two wires. If it's a programmable type... it will require batteries to operate. Most WiFi type stats require an extra wire so stay away from those.
 
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Old 01-09-16, 05:16 PM
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@beelzebob I am replacing the units because they are very old and dirty, and seem very inaccurate.
 
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Old 01-09-16, 05:24 PM
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@PJmax if I wanted a WiFi stat. What is the third wire called that is needed? And would it have to connect direct to the heating system? Also how can I tell which thermostats are compatible with two wires? Is it any low voltage battery powered one?
 
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Old 01-09-16, 05:28 PM
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Currently you have a two wire heating system. So any stat that works with that will be ok.

The third wire is called a common wire and is the C connection to power a stat that doesn't use batteries.
 
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Old 01-11-16, 01:14 PM
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connect one wire to R (leave Rh-Rc jumper) and the other wire to W.
Does it matter which wires goe where? I have a black wire and white wire.
 
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Old 01-11-16, 05:08 PM
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I currently have white to W and black to R. I left the jumper in from R to RC. Its currently not working. Should I take the jumper out?
 
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Old 01-11-16, 05:29 PM
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Does the system work if you just connect the two wires together ?
 
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Old 01-11-16, 09:08 PM
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Actually it did work! I just got home and found a wire was loose(didn't tighten properly). Thanks so much for your help.
 
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Old 01-11-16, 10:50 PM
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Good news. Thanks for letting us know.
 
 

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