Adding a room stat to a Apollo 50Si Boiler

[MartinSullivan]

Hi

I have an existing Apollo 50Si boiler, which seems quite reliable and works well. Until recently this wasnt able to run central heating independantly of hot water, but Ive just had that sorted.

All the radiators have manual TRV's on them but I would like to add a room thermostat to give a little bit more control, Ive ordered a Honeywell CM927 , Im looking for some advice of where to wire in the thermostat relay control module into the boiler. I can find the manual for the boiler which details the 6 pin plug for the apollo controller, but I cant see any pins for a room stat.

If anyone could provide the info it would be much appreciated. First post here so be gentle

Mart

 

[Andygasman2010]

What's more important is the kind of system you have. Is it a Y-plan or S-plan? I.E. a 3 port valve or two 2 port valves.

Is the timer for your heating/hot water integral to the boiler?

By the way, you should really have one radiator without a TRV unless you have a decent bypass fitted.

I assume there's never been a room stat fitted. It'll need wiring into the wiring centre which is probably in your airing cupboard.

 

[MartinSullivan]

Andy thanks for the swift reply, Im learning as I go along

Its two 2 port valves, does that make it S plan?? Ive seen the terms scattered about over t'internet but not appreciated the subtleties.

I read that I should have one rad without a trv, these were all fitted before I bought the property but I checked and there is a bypass fitted, and I leave the bathroom trv wide open.

There has never been a room stat fitted before, the current programmer is in the kitchen and the boiler is in the cellar, I assume there will be the wiring centre down there too but I havent actually seen it, I assumed the relay unit for the honeywell would wire direct to the boiler.

Im going to get a sparkie to install it but just wanted the info to hand of where it should be connected in case he cant work it out.

 

[MartinSullivan]

Ok you pointed me in the right direction I think - just found this

Basically, there are four wires going to the zone valve. (Actually there may
be an additional earth wire, as they seem to be metal cased). Amongst them
should be a brown/blue pair. These control the motor. The blue will be
connected to neutral. The brown will be the call for heat from the
programmer.

To wire in the thermostat, you need to break this brown wire at a convenient
location, preferably at the junction box. Trace the cable back from the zone
valve until you get to the junction box. The two ends of these then form the
switched lines for the programmable thermostat. The receiver may also need a
permanent live and neutral, which you should be able to find in the junction
box too.

So basically I pick up the wires in the wiring centre and use them to switch the zone valve via the thermostat.

 

[Andygasman2010]

The call from the clock needs to go into the stat then back out to the brown on the zone valve. It'll also need a permenant live/neutral. I assume you're putting in a wireless one.

A simple job for any sparky... ?