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Ian Ian is offline
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Default Wiring from Programmable roomstat to remote temperature sensor

Hello Group
Help!
I am advised by manufacturer (Danfoss) that I should use 1.00mm2 two
solid copper core cable to connect their remote sensor to a TP7000M
prog roomstat and that the cabling must not be in close proximity to
any mains cabling.
The original cabling (1mm T&E, earth not connected) ran very close to
mains cabling. This caused wildly fluctuating temperature sensing (as
much as 5 degrees C on consecutive readings,which seem to be taken by
the controller at one minute intervals)
I have now re-routed the cabling to be , for the most part, 8-12
inches from any mains cable. I have used the 1mm T&E again. The
situation is considerably improved but I am still getting fluctuating
readings albeit more in the +- 1 degree C range. If I run a shortish
(about 1 metre) length of cable to the sensor absolutely nowhere near
any mains cabling the temperature readings are totally steady.
Since a reading even 0.5 degree below 'actual' temperature results in
a call for heat which then operates the zone valve and fires the Oil
boiler, the next reading may be at a heat higher than target and shuts
down everything, I can be left with the boiler running in bursts of
1 minute. I would like to avoid this if possible.
Any ideas on any appropriate cable to use - perhaps screened in some
way - or would some form of twisted pair help in any way? Is there any
1mm2 two core twisted pair available?
I'd like to resolve this before replacing
floorboards/redecorating.......
Many thanks for any input
Ian
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Ian