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Anticipator

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Jon S.
Jon S. Member Posts: 43
in THE MAIN WALL
would someone please explain how the anticipator works. What dose the amp draw have to do with the cycle rate?

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  • Tom M.
    Tom M. Member Posts: 237
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    Anticipator

    The heat anticipator actually creates heat in the thermostat so that it will turn the equipment off before the desired temp is reached. This way, you won't have large steam radiators hot and steaming at the end of the cycle when the thermostat is already satisfied.

    The heat anticipator is operated by the current passing through the thermostat and it therefore must be adjusted to compensate for higher or lower current required by the equipment it is operating.

    As an example, if a house is zoned with relays and pumps at .2 Amp thermostat current and the system is replaced with Taco zone valves at .9 Amp, the following will happen if the anticipators are not adjusted. The thermostat will call, the heat anticipator will get 4 1/2 times the current it was getting before and will overheat the thermostat too quickly producing shorter cycles. If there is very mild weather, the thermostat can turn off before the valve is completely open. Hope this helps.
  • Jon S.
    Jon S. Member Posts: 43
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    Thanks

    I love this place. Thanks for the great info!
  • Unknown
    Unknown
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    Good illustration

    just a point of information if you fired up a Taco zone valve with the thermostat set at.2 it will burn up the anticpator. The anticpator can not take that much amperage.
  • Tom M.
    Tom M. Member Posts: 237
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    > just a point of information if you fired up a

    > Taco zone valve with the thermostat set at.2 it

    > will burn up the anticpator. The anticpator can

    > not take that much amperage.



  • Tom M.
    Tom M. Member Posts: 237
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    Timmie,

    a few years ago I got called to a house for no heat. The house was twice the size as it was the previous year and had the furnace removed and replaced with a 7 zone baseboard system with Taco zone valves. It worked fine all winter, but it was the first warm day in spring that I was called. All the anticipators were at .2 Amp. My guess is that since it was a large rebuild/ addition, the zone valves were installed by a plumber and the tstats by an electrician and there was poor communication. All were Honeywell T87's and everything has been fine since I reset them.

    At the time, I thought that the low anticipator setting was limiting the current available to open the valves. Since gaining a better understanding of how the anticipator works, I now think that the tstats were being heated to temp by the anticipator before (or shortly after) they were open. Anyway, that's where my example came from.

    Tom M.
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