boiler ctrl - replacing timer with thermostat

[glider2]

Hi,

I’d like to install a RF controlled room thermostat on this old combi boiler to replace the timer that is currently controlling its central heating function (see photo in my profile). The current timer has a mains input and two outputs to the boiler. Instead of taking it apart, could someone tell me what these outputs are and what specs my new thermostat must have to be compatible with the boiler? The boiler is a "Fer Industrie Hawk" model for which I couldn't find any information online. Thanks.

 

[gas4you]

Only reason I can think of that a combi would have 2 lives to it would be a permanent live and a switched live for heating demand.

Any RF programmable stat should do. The receiver unit will have permanent L, N and a switched live to the boiler ch demand.

If it is a low voltage switched live, then the supply to this side will have to come from the boiler control board its self.

 

[glider2]

Thanks Dave.

As I'm a week-end DIYer, can you clarify what you mean with "supply to this side will have to come from the boiler control board its self."

What are the outputs of thermostat generally? N, L and SwL? And if the L that I connect to the boiler is 220V, will the thermostat handle 220V going through it and out the SwL pole back to the boiler? Because by the looks of things the boiler wants 220V live. I'd basically like to install a thermostat that requires as little change to the wiring in the kitchen. Pls have a look at a pic of the current configuration (in my profile).

Basically I don't think it's a hard task so I'd be very grateful if someone could explain it to me in simple terms that the amateur that I am will understand

 

[Steve]

Firstly, this new "thermostat" you're installing needs to have a timer as well. Dont just have a thermostat. You dont need your house to be 20 degrees all night, and all day.

Leave the timer be, but have its switched output feeding the thermostat. Though I'd be tempted by a new timer - that thing has had its day.

 

[glider2]

Thanks Steve. Can I not just replace the current timer device with a programmable RF thermostat, something like this:

http://www.screwfix.com/prods/93829...g-Controls/Horstmann-Wireless-Room-Thermostat

Or does my boiler (see pic in my profile) require a timer input/need a timer and a thermostat?

Please help!

 

[kwikfix328]

i fitted a Drayton Digistat RF3 to my Worcester-Bosch combi early last year. I kept the existing timer in place and set it for 24/7 and also set all of the downstairs radiator thermostats to max.

The wireless sender unit has an inbuilt thermostat and multi-function digital timer which controls the room temp.

Best thing i ever did, apart from getting the gas main and GCH installed in the first place.

More comfortable heat in the house and the bills went down too...

HTH.

 

[glider2]

Kwikfix,

Thanks for the suggestion. Sounds like a plan. So just to give me an idea before I go out and get the RF thermostat, and if you don't mind looking at the pic of my timer/boiler in my profile, how does the thermostat connect to the existing installation?

 

[kwikfix328]

Kwikfix,

Thanks for the suggestion. Sounds like a plan. So just to give me an idea before I go out and get the RF thermostat, and if you don't mind looking at the pic of my timer/boiler in my profile, how does the thermostat connect to the existing installation?

Sorry buddy I can't help you there. I bought my Digistat Wireless unit as it was a direct replacement for the genune Worcester-Bosch version. The W-B unit being a more expensive re-badged Drayton. I bought mine as N.O.S off e-bay for a very discount price,

My post was really more aimed at letting you know that i found that getting a wireless thermostat was a huge upgrade to my existing GCH system.
The Thermostat did come with quite comprehensive wiring instructions , but that was for my specific units.