Y Plan Headache!

[JAMES_PRIOR]

Brand new boiler, pump, room stat, 3 port valve, cyl stat & programmer fitted. Boiler will only fire when cyl stat turned up and then you can control heating from room stat. when cyl stat turned down the boiler will not fire and heating or hot water cannot be controlled. When cyl stat turned down and you call for heat via the room stat the 3 port valve seems to tick as though the 230v feed is being switched on and off. All wiring has been checked 5 times now my head is ready to go bang!

 

[Guest123]

Hi.

If you are 100% certain the wiring is correct, (Check Here) have you tested at the mid pos valve to ensure correct operation???

Also could it be that the HW OFF/ON is mixed at cylinder stat or the programmer???

 

[JAMES_PRIOR]

Hi Lenny,
Thanks for taking the time to assist!
I re-wired the central heating system myself and have checked all of the connections at each of the stats pump & programmer twice over. I have rewired y plan systems before and have been an electrician for 10 years now but iam starting to doubt myself! Iam going to the job tomorrow to go over it again so just wondered if anyone had come across this problem before.

 

[robsparky1975]

Is the programmer working corrctly?,as you have done y plans before you will already know about the need for hw on/hw off at the programmer and cylinder stat,is the cylinder stat working correctly?,did you use a honeywell circuit board wiring centre if so,did you cut the correct links?,i have found the h/well booklet useful when fault finding,step by step and a quick way to resolve any issues.

 

[JAMES_PRIOR]

The programmer is brand new and i have tested the s/lines at the wiring centre to make sure correct sequence and switching is achieved and the same for the cylinder stat. I was reading somewhere else that it might be a faulty micro switch on the 3 port valve but that wouldnt explain the feed which is only there when the cyl stat is turned up. At the job tomorrow so will check the links again.

Thanks for the ideas guys much appreciated!

 

[vinny electric]

did you sort it out what was the problem

 

[nickblake]

have you ensured the HW off wire has been connected its the white one one the valve, the three port valve are a very clever piece of engineering

 

[ringer]

Have the gears slipped out of sequence on the valve control head? Can you see the gears turning when switched on/off?

 

[emf]

Hi James
Quote 'a faulty micro switch on the 3 port valve'. This would seem a logical explanation, as others have said its a clever piece of kit. I've never delved into its internal workings or observed this particular fault, so I would be interested in the outcome.

My thoughts for tracing stubborn faults on systems using these valves are....Disconnect the orange, white and grey wires and then test for the appropriate inputs at the terminals where the wires were connected ( This being necessary because the internal switching operations cause back feeds) see this link Honeywell United Kingdom Heating Controls

The relevant bit is at the bottom of page 2

 

[liam b]

have you ensured the HW off wire has been connected its the white one one the valve, the three port valve are a very clever piece of engineering

no its not

 

[puddle]

have you ensured the HW off wire has been connected its the white one one the valve, the three port valve are a very clever piece of engineering

HW off on programmer/satisfied on cylinder thermostat is connected to the gray wire on the valve,white is connected to room thermostat /heating demand

The clicking on and off is often a problem with a faulty head

a easy ref site for heating system wiring

http://octaveblue.co.uk/c_heating/index.htm

 

[nickblake]

Opps my mistake ,slap given , must have looked at the pic wrong eyes crossed and all

 

[xtralarge350]

The hot water off wire is grey! not white! On a three port valve. The white is call from the heating. If you've checked all your wiring and are happy with the connections the only obvious cause is the valve, I work on all kinds of heating systems everyday and have done for several years, i would change the valve mate. if its not the valve its your wiring.