Y plan motorised valve problem

[steveboy]

Hi folks ,The problem i have is that when the programmed time as elasped the (honeywell mid postion valve) stays in its last postion ,this causes it to get hot over night and i read somewhere that this isen`t good for them as over time it causes them to burn out .I have checked and double checked all the wiring and seem to have got all the wires from the thermostats in the correct configuration with the boiler ,programmer and valve. MY main question is this " Is it normal for these type of valves to stay in its last position or should it wind back to default position using its return spring when the programmed time as elapsed?
One other thing the boiler still keeps running even thought the room stat is satisfied (within the programed time though)
I have been pulling my hair out for over a year now over this problem ,its not so bad in the summer as only the DHW is called for and the valve doesn`t move but now its winter and both CH and or DHW is called for the problem is back!!!

many thanks and festive cheer
steveboy

 

[so-solar]

It sounds like a wiring fault as the valve is 'usually closed ' therefore it requires power to hold it open, and it sounds like the signal is still being received that the valve is still open therefore the boiler will keep running! check your thermostat mate!

 

[NickH]

If DHW is satisfied first and then Heating is satisfied the valve will stay in its current position and the boiler/pump simply shuts off. If the programmer then shuts off completely (power down) the valve should have no power and so spring back to DHW only (rest position). At least thats how I understand it.

 

[bobpape]

This issue brings my thoughts back to the 1970s when I first started installing pumped
systems,
Initially I got an electrician to wire up the systems but I found they did not think the same as me and the resulting installation often did not perform as I would like,
The only way round it I found was to wire it myself.
This was of course before the event of wireing centres,

Sounds to me like you have the same problem.

If it were me I would grab my multimeter and start again. the worst problem you could encounter would be not enough cables,
If that turns out to be the case I believe you can now obtain wireless controls

it is a bit like the problems encountered with three way and intermediate wiring of a staircase lighting circuit,

 

[steveboy]

Yes, that is what i think should happen ,when the programmed time as elasped the valve should be de-energised and return to its default position using its spring . The problem is how do you wire it to achieve this? It will do it if the heating is switched off first , but when the programmer finishes both DHW and CH at the same time it stays in its last position i.e. still energised and thus getting warm ,which cannot be good for them !

 

[NickH]

Is the valve still powered up even if you turn the programmer completely off, ie DHW and Heating switched to OFF. If it is then you have a faulty programmer or the wiring is wrong.


The wiring diagram for a Y plan is very specific, check through all your wiring connections against the diagram and you should be able to figure out what wrong.

 

[steveboy]

Yes if i turn off the main supply to the programmer then the valve winds back on its spring, like i said it works fine and perfectly normal in all settings i.e. DHT only DHT & CH or CH only,, its when the CH switches off the problem starts i.e. the valve stays in that position.There is a 4core cable coming from the boiler red to live ,blue to nutural ,black to T8 and yellow to T4 , however if i move to yellow to T8 then the boiler wo`nt switch off after the elasped time ,do you think this yellow wire could be the cause of the problem The programmer is a Danfoss CP15 , cylinder stat drayton HTS3 room stat drayton RTS2 and honeywell valve .

cheers
steve

 

[NickH]

I presume that "turn of the main supply" means you are switching off the fused spur to the progammer, yes? What happens when you leave the power on but switch the programmer DHW and Heating selectors to OFF.


Look at this http://content.honeywell.com/UK/homes/FAQ/v4073aop.pdf

 

[steveboy]

Sorry ,yes that is what i meant, if the supply is switched off at the fused spur the valve winds back,if the programmer DHW and CH is switched off it stays in its last position ,however if the CH is switched off 1st and then and DHW is left on for approx another 20-30 second or so the valve will wind back on its spring.
I read the article on the link you provided and my valve does exactly as stated in the last paragraph which i find contray to what others say and seems right.

 

[NickH]

Exactly, when i read it again it does look yours is doing exactly what it should, although I've always thought that with the programmer settings OFF it should power down the valve and let it spring back. I've got the same system here, if I get time later i will see what mine does.

 

[steveboy]

Exactly, when i read it again it does look yours is doing exactly what it should, although I've always thought that with the programmer settings OFF it should power down the valve and let it spring back. I've got the same system here, if I get time later i will see what mine does.

Cheers for that , I look forward to see what results you get

 

[NickH]

Well I played around and my system does exactly the same as yours steve.

Reading the honeywell stuff again I'm sure its exactly what is supposed to happen, it specifically says switching off at the MAINS will de energize the vlave. Even with the prog settings to OFF there is still a live feed (HW off, grey wire) to the valve.

 

[steveboy]

Hi there,

Ok, (today)i went to our plumbing Dept in the school of constructon and have left them with the problem ,they like something to do whilst sitting around in the staffroom!!!!! (only kidding) they reckon it could be something to do with the way the room stat is configured ,however they need a bit more info so i will furnish them with that tomorrow and let you know the results.

cheers
steve