Worcester Central Heating constantly switches On and Off

[stricklandsp]

Hi, I hope that some kind soul out there might help me with a Problem with a Worcester 24cdi combi boiler. The system is controlled by a "Lifestyle 711" timeswitch (standard two timer on /offs per day program))and I have a single thermastat in the hall.
Problem is that when the thermostat is turned down so that it is "off" the Central heating part of the boiler keeps firing up for a few seconds and then switches off after a few seconds and then on and then off..... etc.
If the electronic timer is "off" then no problem or if the themostat is "on" it works fine and heats the water like normal. No problem with the hot water in the taps.
I thought it might be the timer unit so fitted a new one..... no change and still had same problem.
Havnt looked at the wall thermostat and have to say its pretty old but can hear click on and off as you rotate it
Any ideas would be really appreciated . Thanks in advance!!!

[stricklandsp]

Re: Worcester Central Heating constantly switches On and Off

Hi everyone........ cant anyone help me out there? I cant believe that this is the first time anyone has heard of or solved a problem like this.
I have never been unique in my life so hope I am not starting now !!!
Anyone ! Any Ideas !....... all comments and suggestions would be greatfully received!!
Thanks

[TimH]

Re: Worcester Central Heating constantly switches On and Off

What happens with your wall thermostat when your boiler stats cycling? Does that start clicking on & off?

Maybe the contacts in the stat are wearing / arcing and it's time for a new one? They're failry cheap and easy to replace, just watch out for mains voltage on the terminals :-)

HTH,

Tim.

[stricklandsp]

Re: Worcester Central Heating constantly switches On and Off

Thank Tim H...... will try your suggestion. Looks like I do have something to do this weekend!! Also thanks for the warning ref mains power
If it works or not..... will get back to you .
Thanks

[sunbeam]

when you say the boiler fires up, do the radiators get warm? I Think the worcester has an instant hot water device , on the continent when they say instant hot water they mean instant so the boiler goes through a cycle every few minutes to warm up the hot water in the boiler, if your rads are getting warm then maybe the diverter is passing to central heating?

[stricklandsp]

Re: Worcester Central Heating constantly switches On and Off

Hi... thanks for that. The Worcester has a light indicating the CH and light for the HW and a light for the ignition. The light for the CH comes on first and then a few seconds later the ignition light comes on (which is normal before the problem) but then they both switch off. 2 seconds later it comes on again , then goes off etc. The radiators dont seem to get hot but thenthe ignition is only on for a second at most at any one time. As I said it only happens when the roon thermostat is turned down so that it is off. If the thermostat is on then all is fine, as is the HW all of the time. For info when it is cutting on and off the room thermostat seems to stay off ... it certainly isnt making any click sould like it does when you turn it on ........ Any suggestions would be appreciated. I am leaving it running on off on off for a while and will let you know if the radiators get warm .cheers and thanks for the reply

[stricklandsp]

Re: Worcester Central Heating constantly switches On and Off

Cancel my last about the radiators NOT getting hot.......... left it clicking on / off /on /off for hours and they are definately warm!!!

[stricklandsp]

Re: Worcester Central Heating constantly switches On and Off

Well I tried something else last night.....I left the whole system turned off all night at the mains switch so it was stone cold. Turned it back on and first 7 or 8 clicks it was the same... ie on for a second and then off for a second. On 8 or ninth time the burner CH light and ignition light came on abd could hear burner ignite... it stayed on for probably a couple of minutes before going off. Then went back to on off every few seconds. Dont know if this helps but exact sequence of the lights coming on and off is. CH light on ... second later ignition... second later ignition light off.... CH light off.
Does that help or give any clues??
Cheers

[sunbeam]

Re: Worcester Central Heating constantly switches On and Off

Ithink i would concur with timH and try a new room stat.