Hi,
I've just got a Honeywell CMT927 wireless thermostat to hook up to my combi (I believe it's the successor to the CM67). The transmitter bit is going to go in the boiler cupboard itself, but I'm not sure what cable I need for the job.
Here's the relevant page from the installation manual.
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at the bottom right (you may have to enlarge it) you'll see what type of cable it wants.
Looks to me like I could use either one four-core cable or two two- core ones (separate ones for the power supply and the switching signal). The two cores that carry the mains supply should have conductors between 1.5mm and 2.5mm (picture 6) - seems very hefty to me for a little electronic gadget that can't consume more than about
20w. Picture 5b has me a bit confused. Why the greater and less-than 7mm stuff? It seems to be saying that the power supply cable should have an overall diameter of less than 7mm, and the "signal" cable should be greater than 7mm, but that can't be right - must be the other way round.Anyway, TLC seem to stock the stuff for the job:
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was thinking of ordering the four-core 0.75mm stuff, here:
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way I would just have one heat resistant cable between boiler and control box carrying both the signal and the power supply. The conductors are only 0.75mm though, but surely that must be OK (despite the "no-less-than-1.5mm requirement)? It's rated for 6 amps for god's sake.
What does the panel think?
Cheers!
Martin