power to hot water?

[swill51]

Hi all, new to forum. DIYer on plumbing, but have part P electrics.
Need help! had new boiler fitted, which then had issues with wiring.
Potterton Promax boiler, Lifestyle Lp722 timer , Y plan with with honeywell 3 port and honeywell L641a1005 cycliner thermostat, all but one rad have TRV's.


Seems to be all sorted now except with the hot water.
i am getting power to the hot water tank cyclinder all the time regardless of time clock settings. If i turn the temp setting then this either fires the boiler or not. having checked continuity done the different wires, all seems to be okay! Hot water calls fort heat and shuts off fine.

Am I correct in thinking that the power only comes throughthe timer, therefore there may be a fault with the timer?

other things i have tried, is to reverse the connections on the hot water cyclinder, then what happpens is that the call for heat works in reverse, so changed back.

inside the timer it is wired so that there is a HW off and HW on, but as said at the momoent its always on.

Checked the jumper this is set to P, fully pumped independant HW CH.

any ideas

thanks

steve

 

[Bob Croft]

Y plan system defaults to HW in the absense of power to the valve. Thus if the cylinder stat is satisfied then you need to check why the boiler is running, assuming the central heating is not calling for heat. Have you checked that the cylinder stat is wired correctly?

 

[Puddle]

well if hot water going on and off ok you should be ok

you will get a live feed to the satisfied contact on cylinder thermosat when everything off at programmer as this is from hot water off terminal on clock and runs also to grey wire on motorised valve
This allows the heating to work by its self when heating only turned on at programmer the power supply will the be joined by power to the white cable on valve giving heating only position= grey and white

If programmer off and hot water operating,ie power to cylinder stat common,disconect switch live from clock and see if still power to thermostat,this will let you know if programmer faulty or faulty wiring in wiring centre,is it a prewired wiring centre,if so are all loops cut as required

 

[swill51]

Tried disconnecting the switch live at programmer, no power to cyclinder stat. however the Ch doesn't work either now?

the wiring centre, definately is not pre wired!!! there are no loops? Previously there was a link between the white and orange wires, i removed this as wasn't shown on any wiring diagrams with boiler or for the Y plan. this link propably supplied the power back to the pump for CH, should i replace this? or should the 3 port valvle send the power back through the the orange. this is also a new unit, as the last one was shot.