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Y87RF Single Zone Thermostats
Posted: Tue Nov 22, 2016 8:54 am
by Jornada123
My Y87RF Single Zone Thermostats are consistently around 1 degree C different to the temperatures shown on the Evohome Controller.
Is this normal, and which is correct?
Re: Y87RF Single Zone Thermostats
Posted: Tue Nov 22, 2016 2:37 pm
by Richard
My T87RF is showing 19.5 degrees on the device and 19.5 degrees on the evohome Controller. Where is the evohome Controller located? Any other RF/Wi-Fi devices anywhere near it?
Re: Y87RF Single Zone Thermostats
Posted: Tue Nov 22, 2016 10:07 pm
by DBMandrake
You haven't rebound the HR92 at some point by any chance ? Does the reading on the HR92 (if you configure it to show room temperature) match the reading on the controller ?
If so what might be happening is that rebinding it has nominated the HR92 to be the temperature sensor for the zone - which means the the temperature sensed by the HR92 will be displayed on the controller instead of the temperature sensed by the Y87RF, and typically an HR92 will read about 1 degree hotter than room temperature (and the temperature sensed by a wall mounted sensor) when the radiator is hot.
The Y87RF will continue to measure and display its own temperature reading but this reading will be ignored by the controller and will not be used to control the radiator, even though you might still be able to control the set point from it. I've done this before on purpose during testing with a DTS92 to see what would happen, just because I like to know how things work.
To fix this you would want to re-bind the Y87RF as the temperature sensor for the zone - long press on settings to go into the installation menu, zone configuration, choose the zone, choose temperature sensor then remote sensor, then follow the steps for putting the Y87RF into binding mode.
Then leave it back on the home screen for about 5 minutes and you should notice the readings come into line with each other if my suggestion was correct. Although there can be some delay in the reading from a wall stat being displayed on the controller if the room is heating or cooling quickly they should always agree after a short time, and if the room temperature is constant, there should never be a constant 1 degree discrepancy.