Replacing Thermostat / Timer

[gwltabb]

As my previous post suggested the timer is no longer working on the Boilermate II cylinder. As this was never much good in the first place I thought this is a good excuse to fit a wireless thermostat/timer, if its possible!

I've got a thermostat that is in the hallway downstairs, the boilermate is upstairs. As the timer isn't working on the cylinder I'm just using the thermostat to control on/off. So:

1) Is this set-up OK to install a wireless thermostat/timer?
2) If so, what do I need to be looking for? I heard Drayton are good components. Will any work or only certain types?
3) Once I've got it, how does it set-up? I know there is a sender and receiver, does the receiver need to be attatched to the wireing in the Boilermate or replace the existing thermostat?

Thanks in advance.

 

[gwltabb]

After doing a bit of reading in the last half hour (sorry, should have probably done that before posting!), I see that it might be better (and cheaper!) to simply replace the existing thermostat with a newer one which has the timer functionality. It is currently a Honeywell (can't see a model number).

Same questions apply I think, what can I replace it with, and how easy is it to wire in.

 

[gwltabb]

Can anyone help me with this? Ive found out the current thermostat is a Honeywell T6360. Really can't carry on with having to run downstairs to turn on the heating much longer! - was freezing this morning!

 

[D_Hailsham]

1) Is this set-up OK to install a wireless thermostat/timer?

Yes

2) If so, what do I need to be looking for? I heard Drayton are good components. Will any work or only certain types?

Honeywell are better. The CM921 or CM927 are very good.

3) Once I've got it, how does it set-up? I know there is a sender and receiver, does the receiver need to be attatched to the wireing in the Boilermate or replace the existing thermostat?

The receiver is wired to the Boilermate. This could be direct or using the existing thermostat wires (but see below about wiring). The transmitter (control unit) can be located anywhere within range of the transmitter as it is battery operated.

I see that it might be better (and cheaper!) to simply replace the existing [Honeywell T6360] thermostat with a newer one which has the timer functionality.

Yes, you could do this using a Honeywell CM901 or CM907 programmable thermostat.

The wiring for the wired version is exactly the same as for the wireless receiver. There should be three wires going to your existing thermostat: Live, Neutral and Switched Live. These just connect to the appropriate terminals on the CM901/CM907 or CM921/CM927 receiver.

A word of warning! Many lazy installers use a standard three core (Brown, Blue, Green/Yellow) cable for the thermostat wiring with the Green/Yellow used as the switched live. So do not assume the Green/Yellow wire is an earth wire. Ideally a proper three core cable, (e.g Brown, Blue, Black) or three core plus earth cable should be used but, if this is not possible, putting red insulated tape or sleeving over the green/yellow ends of the wire is "acceptable."

In both cases, wired and wireless, the BoilerMate II clock should be set to Always On.

Link to BoilerMate II Installation Manual, which has wiring diagrams.

 

[gwltabb]

Thanks very much for the reply.

I see the CM901 is a three wire connection (as it the current thermostat) where as the CM907 is only 2. I assume I will just need the live and switched live for this and isolate off the neutral?

Just one other question, as I'll try to fit this one night this week, its going to be dark so will need the lights on. Will turning off the boiler trip switch at the mains cut the power to the thermostat as well (as its connected to the boiler?). I suppose the safest will be to wait until next weekend and turn all the power off but if I can do it sooner that would be preferable.

 

[D_Hailsham]

I see the CM901 is a three wire connection (as it the current thermostat) where as the CM907 is only 2.

I made a mistake in my last post. The wired versions (CM901 and CM907) just need a live and switched live - no neutral. The wireless versions (CM921 and CM927) do need a neutral to power the electronics in the receiver.

If you go for the wired version, just make the neutral safe at the thermostat end (insulating tape).

Will turning off the boiler trip switch at the mains cut the power to the thermostat as well (as its connected to the boiler?). I suppose the safest will be to wait until next weekend and turn all the power off but if I can do it sooner that would be preferable.

There should be a fused spur somewhere (either near the boiler or theBoilerMate) which supplies power to the central heating, including the thermostat. You shouldn't need to turn off at the fusebox. Most likely better to do it at the weekend when you have more daylight and time to pop to B&Q for the bits you have forgotten.

 

[gwltabb]

Hi,

just to complete the thread, I installed this last night, took me 10 minutes, worked like a treat. As you said, Live in A, swich live in B (which was a yellow sleeve!). House lovely and warm at 6.30 this morning!

Thanks to D_Hailsham for his excellent advice.