Replacing old Honeywell thermostat

Mar 02, 2004 6 Replies
P

Hi,



I've just moved into a new house and found that the cover for my room thermostat is broken, so I thought I'd better replace it. I don't know what the model number is, but there is a simple wiring diagram on hte inside (live, neutral and the wire to the central heating controller). The terminal that connects to the central heating is number 3 and marked 20(4)A - do I need to get a new thermostat with the same rating, or would a 10(4)A be up to the job, as that's the highest I can find locally. If this isn't enough information, let me know what else is needed for me to find out.



Thanks,



Paul


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I

That will be fine if running a normal gas boiler, pump, zone valves. Running an electric heating system? Then it is a case of assessing the current loading.

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C

If this is for a normal central heating system, then the entire system will be fused at 3A, so anything that can cope with that would be fine.

Christian.

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L

On Tue, 2 Mar 2004 09:46:55 -0000, in uk.d-i-y "IMM" strung together this:

If it's electric I doubt all the heaters will run through one stat, it'd be more than 20A. Any standard room stat will suffice. ..

SJW A.C.S. Ltd.

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I

It could be zoned or whatever. The main point is assessing the loading and getting a stat to suit.

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M

It depends what load the thermostat is connected to.

20(4)A is a 20 amp resistive load / 4 amp inductive.

What size fuse does the central heating system use, this should give you some idea of the load.

You might want to consider a programmable thermostat. They cost more but as well as allowing you to vary the temperature during the day with maybe a different program at weekends, they also provide a much more precise control of the temperature.

Michael Chare

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P

It's just a simple Y-plan, gas heating system for a semi-detached house, so it sounds like it would work. Thanks for your help (also goes out to the rest of the thread!)

Paul

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