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  1. #1
    Join Date
    Aug 2010
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    Question thermostat / switching relay conundrum

    So I purchased a couple wifi thermostats to replace my existing ones. They require a "C" wire for installation, and neither location currently has one. The first floor location has an unused wire, but I'm not sure where to hook it up. The second floor location I should be able to run a new wire to without too much issue.

    The switching relays as shown in the picture only have terminals for 2 thermostat wires. There doesn't seem to be any place for the C wire.

    On top of that issue, the relay for my first floor zone isn't putting out 24V like all the others. It seems to be 15V between the 2 terminals. But what confuses me more, is the bottom terminal is at about 4.5V when compared to the neutral wire or the box. It seems that the transformer is slightly out of phase with the line voltage?
    Any suggestions? Does this sound like a bad transformer? Bad connection somewhere? Is it actually a 12V relay? Should I just bite the bullet and buy a new switching relay? I'm kind of stumped here.

    BTW, this is for a FHW oil boiler. 4 zones including the indirect water heater. The first floor is the only one that isn't reading 24-26V
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  2. #2
    Join Date
    May 2006
    Location
    Philadelphia, PA
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    The site rules prohibit DIY asssistance. Time to call a technician that understands your system. The 24 v is available. You need to know where to look.

    There are a few different things that can cause the voltage you are seeing with the relay. Probably can be repaired without replacement.
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  3. #3
    Join Date
    Dec 2007
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    Personally, boilers should be set at one temp and left alone.

    There really is minimal advantage to setbacks. With that said, any use of a WiFi stat is almost pointless.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

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  5. #4
    Join Date
    Aug 2010
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    Thread Starter
    Quote Originally Posted by pacnw View Post
    Personally, boilers should be set at one temp and left alone.

    There really is minimal advantage to setbacks. With that said, any use of a WiFi stat is almost pointless.
    As an engineer with a masters in sustainable energy, I respectfully disagree, and so does physics.

  6. #5
    Join Date
    Aug 2002
    Location
    Southold, NY
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    Quote Originally Posted by tyme2par4 View Post
    As an engineer with a masters in sustainable energy, I respectfully disagree, and so does physics.
    That figures.

    With a Masters Degree you should be able to figure it out!

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  8. #6
    Join Date
    Aug 2010
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    Thread Starter
    Quote Originally Posted by pecmsg View Post
    That figures.

    With a Masters Degree you should be able to figure it out!
    As a matter of fact, I did.

  9. #7
    Join Date
    Dec 2005
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    Sorry Per site rules no DIY

    Thread closed

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