Room Stat

[dormermike]

Hi,
I have a floor standing ideal mexico 2 boiler, TRV's on all rads but i'm considering putting a room stat in the living room.

Is it straightforward to do, generally? System has a basic 24hr electronic timer at the moment.

I'm not sure where the stat would wire into?

Thanks
Mike

 

[ianniann]

A stat is important, otherwise your boiler will keep firing even when the house is warm. With British Gas prices, this doesn't make much sense.

The stat is wired into the boiler. This is very simple but usually involves removing the boiler casing. In your case you already have a timer which will be wired into the boiler, so you shouldn't have to remove the case. Your stat should go "between" the timer and the boiler so that both the stat and the timer have to be "on" to make the boiler fire. "Between" means electronically, not physically. Physically the thermostat should be placed somewhere away from external heat sources (including the sun!) and in a room where the radiator doesn't have a TRV. This used to be a hallway, but now is more commonly a lounge area.

You would need to confirm the exact type of timer and thermostat to get more details. Electronic timers usually require a live supply in addition to the switched supply, or frequently the switched supply is also used as the wired supply. Old style dial/click thermostats didn't need any external power but newer electronic ones do, and you might have to run a separate wire to provide this. You can't just stuff the thermostat in the middle if the timer is using the switched wire to get its mains power.

Or you could replace the existing timer with a version that includes a thermostat.

 

[dormermike]

Thanks for the great info! Makes sense to have the stat between boiler and timer.

My timer is a basic honeywell one similar to link below. I think its faulty becuase the water comes on at odd times,.outside of the presets.

http://t2.gstatic.com/images?q=tbn:ANd9GcQ2Ge2YGre36N47P4-EMTEy-t363VaMDSUqEzBUE78o9iEVKY5Q

I havent decided on a stat yet, and may update the timer anyway. If there was such a thing as a direct replacement for my current timer but with seven day timer and wireless stat, that would be ideal!

 

[petit_pablo]

Pretty much all iannian wrote there is inaccurate and wtf has BG prices got to do with it.

You need to find out what type of system you have first.

How many pipes come off the boiler?
Where is the pump and is there 1 or 2 motorised valves in airing cupboard or near boiler?

The thermostat needs to be wired between the timer and whatever controls the heating (pump or motorised valve).

 

[petit_pablo]

I havent decided on a stat yet, and may update the timer anyway. If there was such a thing as a direct replacement for my current timer but with seven day timer and wireless stat, that would be ideal!

You can get a direct replacement unit for the honeywell st699 and a new wireless stat. Most wireless stats that have built in 7 day timer will only control the heating and you wont have time control over the hot water.

 

[dormermike]

I havent decided on a stat yet, and may update the timer anyway. If there was such a thing as a direct replacement for my current timer but with seven day timer and wireless stat, that would be ideal!

You can get a direct replacement unit for the honeywell st699 and a new wireless stat. Most wireless stats that have built in 7 day timer will only control the heating and you wont have time control over the hot water.

No control over hot water? Seems a bit odd?

 

[dormermike]

Pretty much all iannian wrote there is inaccurate and wtf has BG prices got to do with it.

You need to find out what type of system you have first.

How many pipes come off the boiler?
Where is the pump and is there 1 or 2 motorised valves in airing cupboard or near boiler?

The thermostat needs to be wired between the timer and whatever controls the heating (pump or motorised valve).

Thanks, but what hasnt bg prices got to do with it lol

Its a Y plan, one motorised valve and pump is near HWC and MV.

 

[petit_pablo]

Ok lovely

The thermostat receiver will need to be wired between the Ch ON from the timer to the White wire from motorised valve. It will also need a permanent live and a neutral. A single 5 core wire will be sufficient as this will have an earth too, even if the receiver doent need one.

Easiest way is to mount the wireless receiver in the airing cupboad. This cuts down the need for lots of wires.

 

[dormermike]

The thermostat needs to be wired between the timer and whatever controls the heating (pump or motorised valve).

Idont understand this bit though, neither the pump nor mv control the heating do they? The suggestion by iannan makes more sense, ie the timer is on constant and the stat can break or make that connection depending on room temp?

Not doubting anyone just trying to understand... I'll have a google too. Sounds straightforward though and more importantly im not hearing anyone say installing a stat is a waste of time.

Cheers

 

[petit_pablo]

Ignore the pump bit, i was covering my bases in case you had a gravity HW and pumped heating system. You do not so dont worry about the pump.

The motorised valve switches the boiler on, not the timer.

When you turn heating on, valve will move to heating position, making a switch and powering the boiler.

Search google for a honeywell Y plan wiring diagram.

 

[bengasman]

Before you start changing things, have a look at this.

Central Heating Control Use

 

[petit_pablo]

Before you start changing things, have a look at this.

Central Heating Control Use

Yours by any chance

 

[bengasman]

Before you start changing things, have a look at this.
Central Heating Control Use

Yours by any chance

Indeed it is. I was told that one of the keyfactors for Google to bring you up in the rankings, is to provide original and helpful content.
I think this page qualifies as such. It has very little commercial value for me, but it does improve the overal appreciation for my site from Google.

 

[petit_pablo]

Does it get many hits?

 

[bengasman]

Don't know the hits on individual pages, still have to install the code for that; bigger fish to fry for the time being. All I know is that the total hits are steadiy increasing, and the bounce rate is low.