central heating Timer

Ruski

I believe that you have a combi boiler: this produces hot water whenever you turn on a hot tap and has nothing to do with the setting on the Randall timer that you have.

The reference to 'twin channel' is the ability of the programmer to control the heating and/or hot water on a conventional system (not combi) where you have a stored cylinder of hot water which you would require to be heated throughout the year whether or not the heating was on, this is done with two 'channels', one for heating control, one for hot water control.
This is why I believe the Randall is left over from a previous system, and now that you have a combi the timer is really only controlling one 'channel', i.e.. the heating.

Immersions are not generally controlled by this sort of timer, it's normally the case that an immersion is just a backup in case the boiler fails.

HTH

Russ

Seronera

A High flow 400 is certainly acombi......I fixed two last week.......in the same house!.......big house.

A Randal/danfos 102 has a digital replacement you can just slot on the existing backplate.Its not the very latest thing but it does upgrade it. It will of course only control the heating on a combi. Can't remember the model number right now

Here you are. Expensive if you buy new, but cheap if you are into recycling. It just slots straight onto the existing 102 backplate. Easy peasy. Its a Danfos 102E7.

http://www.ebay.co.uk/itm/DANFOSS-102E7-mini-programmer-/221749072961?pt=LH_DefaultDomain_3&hash=item33a1465441

globalds

Just an update for all those who posted things to help.

I bought a Nest and I fitted it today, it all looks good.

r2015

It has to be asked why a dual channel timer is used with a combi boiler... unless I've mis-read the info?

My combi boiler has a pre-heat function that can be made to switch on and off so that you can have pre-heated water at certain times of the day.

This can be controlled by a programmable thermostat.

I was going to have that and was told it was overkill and all I needed was a room thermostat.

Surprisingly, or not, that advice was correct.

I have no need of a pre-heat function, though this can be turned on at the boiler if I want, and it can also be timed.