Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Low Voltage(?) thermostat

I want to replace my old Honeywell round thermostat with a NON-programmable digital thermostat such as the Honeywell RTHL3550D... My current thermostat has 2 wires marked R & W. I measure about 31.5VAC across them... The Honeywell RTHL3550D is rated for 24VAC... Is this safe to hook up to my 31.5VAC? This is my 1st posting here... Thanks for your help!

<img src="http://i70.photobucket.com/albums/i85/gemstonian/IMG_20121229_142012_zpse37750fd.jpg" alt="" />

<img src="http://i70.photobucket.com/albums/i85/gemstonian/IMG_20121229_141822_zpsebca9e4d.jpg" alt="" />


  • Zman
    Zman Member Posts: 7,467
    24 volt

    Your 31 volts is a bit high. I don't think you will have trouble with the new t stat but it may indicate the your transformer is going bad. 28 is as high as I normally see. What voltage do you have at your 120 v receptacles?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • low voltage(?) thermostat

    My line voltage measures about 111VAC...
  • billtwocase
    billtwocase Member Posts: 2,385
    24 volts

    that is what that one is. As Zman said, check incoming voltage. 
This discussion has been closed.