Wireless thermostat advice

[D_Hailsham]

Would this work -

Honeywell CM 927 connected to three receivers, one each for up and down and a third for hot water. CM 927 would act as the downstairs thermostat and I was thinking of the Y6630 to act as the upstairs wireless thermostat?

Not quite. The CM927 is a single channel device consisting of the control unit and the receiver. The Y6630 thermostat is also a single channel device with a control unit and the receiver. You must realise that, if you do it that way, there is no independent control of the times of the upstairs heating. You cannot use the CM927 to control both downstairs and upstairs. The only way to have separate times is either to have a second CM927 or have a programmer and the Y6630B. Incidentally Honeywell recommend having a third receiver which co-ordinates the other two, so you don't get one receiver turning the boiler off and, at the same time, the other receiver is trying to turn the boiler on. You will need to contact Honeywell to find out how this is done as they don't publish any info!

The Hot water will not require a wireless thermostat as it will be in the cupboard with the HW tank and valves - you can use a wired thermostat and a single channel timer for that. If you decided to use a Y6630B upstairs you could have a two channel timer, one for the upstairs heating, the other for hot water.

You need to think carefully about what you need and cost the options.

The valves and hot water tank are to be located in a separate room to the boiler. What would I need to fire the boiler up?

Having everything in the one room makes wiring the valves, receivers and one/two channel timer much easier. Everything will be wired into a junction box aka wiring centre. All you will then need is a cable from the wiring centre to the boiler. Do you know which boiler you are having? Most modern boilers require a permanent electricity supply, so you need to know where the power is being obtained from. The whole heating/hot water system should be controlled by one fused spur or an un-switched plug and socket. This means that power can go to the boiler and then to the wiring centre; or the other way round. You should not have the boiler supplied from one source and the wiring centre from another.

Just a side question, who should be installing this, plumber or electrician?

If the plumber knows what he is doing and is Part P qualified, then he should; if not use an electrician. The only problem is that many electricians have no idea about wiring up central heating systems - it's a Catch22 situation.

 

[fetster]

Again, many thanks for your reply, I owe you a pint!!

I was under the impression that with the CM927 being able to control 4 zones, one zone could be downstairs and the other could be upstairs, however this doesn't seem to be the case.

Would i be better going for two of the Y6630B's (one ofr upstairs and one for Down) and then wiring in a programmer that will control upstairs, downstairs and hot water? - I assume this would be a 3 channel timer? If this is a good option, could you also reccomend a decent 3 channel timer that has 7 day, multi on /off and all the other usual stuff.

Everything apart from the boiler will be in the one room. The boiler is a valiant but I'm not sure of the model. There is a fuse spur next to the boiler and two fuse spurs in the cupboard where tank and other stuff will be.

 

[D_Hailsham]

I was under the impression that with the CM927 being able to control 4 zones, one zone could be downstairs and the other could be upstairs, however this doesn't seem to be the case.

Unfortunately, that is correct; each Heating zone need its own CM927 control unit. This is because the temperature sensor is inside the control unit. The "zoning" feature just ensures that the calls to the boiler are synchronized so one receiver is not trying to shut the boiler down while another is trying to start it up.

Would I be better going for two of the Y6630B's (one for upstairs and one for Down) and then wiring in a programmer that will control upstairs, downstairs and hot water? - I assume this would be a 3 channel timer? If this is a good option, could you also recommend a decent 3 channel timer that has 7 day, multi on /off and all the other usual stuff.

That is an option. Horstmann make a three channel programmer, the H37XL and the H37VXL. The XL has 230v switching and the VXL has volt-free switching; so you need to check with the installer which one is required.

The boiler is a valiant but I'm not sure of the model.

Have you asked Vaillant what they advise for an installation with two heating zones and one hot water zone? They have their own line of thermostats, programmers etc.

There is a fuse spur next to the boiler and two fuse spurs in the cupboard where tank and other stuff will be.

Best practice is to use only one fused spur for everything. But if this is impossible, each spur should be labelled to show there is a second spur - you would not want to electrocute your friendly plumber!