Big help please, new room stat does not work.

[boxbrownie]

Hi, first of of all I hope all had a good Christmas, we did until boxing day when the CH pump siezed, no problem I thought, whip down to B&Q/Wickes and pick up a new one, which I duly did, while I was there I decided to replace the 25 year old Satchwell room thermostat with a new more accurate design, easy peasy thought I

Replaced the pump no problem at all, my son was busy replacing the thermostat at the same time.....unfortunately after turning everything on and bleeding the system I had hot water but no heating, it appears the thermostat is not doing its job, so we put the old stat back on as a temporary fix....but now the old stat no longer works the system, we are sure we wired it OK, after all it seemed straight forward, but I am at a loss, cannot get the CH to work at all unless I turn up the hot water and open the diverter valves.

Could somebody please look at the piccies and tell me where I have gone wrong? The wiring colours on the cable to the stat bare no resemblance to anything I can find in the manual for the boiler (Halstead Best 80) and the programmer (Horstmann C27).

Untitled

• boxbrownie
• 27 Dec 2010
• 1

Untitled

• boxbrownie
• 27 Dec 2010
• 1

Untitled

• boxbrownie
• 27 Dec 2010
• 1

Any help would be very welcome...we are freezing here

Best regards David

 

[boxbrownie]

Well after all the fuss yesterday and this morning we decided to give it one last go, we wired it up EXACTLY the same way as we thought originally which was
EARTH > EARTH
Yellow > No3
Blue > No2
Red (live) > No1

And now we got CH again....but hang on....we did all this yesterday, and left it for at least 5 minutes each time we fiddled, but the pump never turned for the CH only when HW was on....but this afternoon.....it all works again

If anyone can see a flaw in my wiring please let me know.....although I will be reluctant to change anything again

Best regards David

 

[namsag]

Wired correctly, there is a microswitch in new roomstat perhaps it was sticking if its all working ok now

 

[boxbrownie]

Thanks for the reply Namsag, that at least puts my mind at peace....I did something correct for once

I can only assume it was something like that, becasue we poked and prodded and checked every connection we could find and nothing got it going yesterday, talk about frustrating....and on bloomin' boxing day to!

Best regards David

 

[boxbrownie]

Well we thought we had it sussed....but now the CH will not seem to work if left to the programmer to turn on, if I turn on the HW on the programmer or leave the programmer to auto turn on the HW we get the heating working as well........but nothing I do on the programmer CH controls will start the pump and get the boiler and system to turn on!!!

I can only assume its the programmer gone wierd?

I notice on the programmer wall panel there is just four wires going to the contacts....can I check the system but shorting out the two pairs?

I won't do it unless confirmed of course!!

Best regards David

 

[namsag]

When you select HW ONLY do the rads heat up

OR

If the CH is coming on while the HW is selected and untill the cylinder stat is satisfied then this suggest the CH motorised valve is not opening properly and making the microswitch inside it to bring the boiler and pump on ,
Usually requires new head or complete valve depending on which make and type.

 

[boxbrownie]

Hi thanks for the reply, strange thing is the system doesn't seem to want to turn on in the morning although I have the CH switched to 24hrs.

I will try the HW only this afternoon after giving the rads time to cool down, I am not sure that is the total problem because although the rads heat up when the HW is on the HW is on several timed events during the day, when the HW is timed as an off period the CH still appears to be going strong.

At the moment the HW is timed "OFF" and the CH timed "24hr" if I turn room stat to high heat the system turns on.....so appears to be working as it should. But the system still does not turn on in the morning until I have "boosted" the HW on the programmer. I can hear the motorized valves (Honeywell V4043H1056) turn, or at least the motor operating during certain events, so something is working there.

The strangest problem seems to be the failure of the CH to turn on in the morning despite being set to 24hr ie on all the time!

I will turn the heating off this afternoon and set the hot water to 24hrs and see if the rads continue to be heated, I guess thats the next avenue of investigation?

Best regards David

 

[boxbrownie]

OK so the rads start going cold after about an hour or so with just the HW turned on, if I then switch the CH on there is a motorised noise from the CH valve and the rads get hot.

This early morning thing is my puzzler, if there is a microswitch in the CH valve is it possible this is not switching when the valvel turns, as the little manual lever on the valve doesn't "go back" all the way when it turns off, seems to travel not very far and there is a lot of loose play in the lever if pushed manually.....if I push it manually to open there is maybe about a third to a quarter of its travle that has a resistance on the lever before the end of travel. I hope this makes sense?

Best regards David

 

[boxbrownie]

Had a look under the cover on the CH motorised valve and although using the manual lever does not travel far enough to activate the microswitch, with the cover off I can see that when the valve is eletronically motorised the vlavle inside travels enough to activate the microswitch, so I am assuming that the valvle is working as it should be, which is a bit annoying as I thought I might have tracked the problem down, but at least this may have saved me £60 for a new valve!

Maybe it is the timed programmer not actually activating the CH circuit, although it works when the CH button is pushed on the programmer manually?

Best regards David