Devireg underfloor heating controller problem

[Tim Downie]

We've had electric underfloor heating installed in our en-suite loo but the programmer is causing us some grief.

's set to come on twice a day but I frequently find that the floor is heating up outside the programmed times. I thought at first that maybe a relay was sticking and it wasn't going off after a normal "on" period but I've just found it on when it was defintely off beforehand.

It's set up to work of the floor sensor only and not the room stat as the controller is outside the bathroom.

I'm 99.9% certain I've set it up right and the only explanation that the instructions give for coming on at the wrong time is if the ambient temperature is too low for the room stat (which is disabled) causing it to come on. Our room temperature would have to drop to -5C to trigger this.

Before I replace it, is there any thing I've missed or am doing wrong? You can see the instructions here.

[Colin Wilson]

It's a long shot, but our controller has a movable link inside which changes the heating mode from...

a) only switch on between irrespective of current temperature b) try to get up to temperature by and maintain until

[BigWallop]

You say you have the floor saver to a temperature of -5 degrees, but, according to the instructions, if you set a -5 degree setting, it only lowers the temperature by 5 degrees from the maximum temperature you selected in the first part of the set up process.

Which means. If you have set your heating to reach a maximum of 45 degrees Centi' and a floor protect temperature of -5 degrees. the controller will drop the temperature to by -5 degrees to 40 degrees Centi'.

If you want to stop the heating coming on all together, then you'd need to cancel the floor protection mode, or set it drop the temperature by the same amount, or more, as you have set the maximum temperature you want.

Hope that makes sense. Read the instructions again, and keep reading them until you fully understand what everything means.

[Tim Downie]

Thanks.

After I posted I did what I should have done first, namely phone the makers.

They confirmed what you've said that the -5C was the offset, not the minimum, meaning that it would come on if the floor temperature dropped more than 5C from the pre-set temperature, whatever the time clock said. Seems a bit daft to me when I've already disabled the room stat and judging from the response by the makers, it's a very well known stumbling point in the set-up. I think the instructions are biased towards using it as total room heating rather than as an intermittant foot warmer.

The cure is to turn to offset temp to minimum (-30C) and then it (more or less) only responds to the timer, not to changes in ambient floor temperatures.

Cheers

Tim

[auctions]

The DeviReg is a 'smart' thermostat. You set the times you want the room to be warm and it turns on (and off) earlier to allow for warm up and cool down. It gradually improves the accuracy of the timings. This does mean that it will be on outside the set times.

A

[BigWallop]

The instructions are a little confusing, aren't they. :-) Tell me if this

makes it any clearer.

If the link don't work, gives a shout back so I can fix it for you.

[Tim Downie]

Sounds altogether too complicated for a a simple soul like me! So I

*shouldn't* be setting it to come on an hour early to ensure the floor's warm when I want it warm?

Tim