changed the programmer

dandowding

I recently changed the old programmer on the central heating/hot water. It was a push in selector timer, and I have changed it to a digital one. I literally took the wires out of the old and put them back in, in the same positions, in the new one. Now the people in the house say that the central heating doesn't heat up ?! the hot water is ok, but cold rads .

Any ideas?....Anybody ??

bockster

i guess one of two things;-
the programer is not configured correctly, is it set up properly, switches in correct positions, the are sometimes dip switches on board that may need setting. check the instructions very carefully.

or

not wired correctly, even though you think you've wired it like for like, it may not be that simple. electrician or capable handyman required to check it out. recommend you keep the old programer to aid problem solving unless you've allready binned it.


ps. its not just a room stat issue is it?

AndysDad

I did exactly the same job.I replaced my old Switchmaster 805 with a new electronic one and with the new programmer I had the conversion wiring diagram so it was a very easy job and all worked 1st time.Did you have any instructions with your new programmer?

dandowding

Yeah, I had instructions. guess I'll have to read thru them again carefully.
thanks

sarahcc

do you have to buy specific timers or like for like when replacing old timers? I have a switchmaster 400

latecomer

As the others have said its definitely not normal for the 2 controllers to be wired the same but most replacements come with a conversion chart to show how to wire them up from the existing one.

Failing that the best thing to do is get the instructions for both and you'll need to figure out the conversion yourself. If you are having trouble post the make and model of both and I'm sure we can help you out.

sarahcc

thank you both for your replies, I feel more confident to go and purchase a timer now that I know I will not be wasting my money.

latecomer

I've recently fitted the Danfoss FP715Si that andrew-b linked and its simple to do and easy to set up. The only downside is that if you use the central heating boost button you get hot water too and this cant be changed. I dont know whether this is normal for other controllers. Apart from that no complaints at all.

jmatt74

Hi, can you tell me which digital timers are compatible with the Switchmaster 805?

Thanks.

AndysDad

jmatt74 wrote: »

Hi, can you tell me which digital timers are compatible with the Switchmaster 805?

Thanks.

I think most of the digital programmers are compatible.I fitted a Horstmann H21 as a replacement for my 805,which I think is quite old now and has been superceeded.The best solution is to go into either a independant supplier or B&Q and ask them to advise you which ones can be used.