worcester green star 18 ri boilers and y plan

[mortman]

so weve had stelrad elan boilers replaced in rental houses with system boilers teh stelrad hadnt died we just thought time to chamge I had a worcester combi in a house in worcester (the tenant worked for WB ) and recomended ok so we specified Wb boilers

we lived in one house and the installer ( nt wb but gas safe- installed the boiler Fine all great but... year on

so now i retire as a BCO sell our home and move into a rental house - same house type same 4kw solar PV same diverter same immersion in same hw cly etc . but the heating will come on with timer firts time ...but wont go off. we live thru the winter hot house cold water.

i ask the prev tenant and he says oh yes timer never worked boiler was always on !! yess used to see the plume so yes for almost 3 years .. meanwhile weve replaces pumps - always hot to touch 3way values again always hot even when boiler isoalted cyl stats etc but only solar water heating

try to get a heating engineer to sort out he tries ...no good you need a combi . no i dont ta and the boier ie 3 yeras old

get a proper registered sparky he cant understand it spends hour on it


I now wonder about the other house with solar and ri and you guess they too are on or off no timers why hasn't anybody complianed

so i set about tracing all the wires from rm stat programmer etc and eventually putt in a 9 terminal block numbered and swop the wires on my house to current and corret setup great the heating obeys the timer but the hot water only works on solar any ideas

oh one house had a easycontrol 200 (via the adaptor) fitted and that too doesnt work HW . to recap we've tried 3 heating engineers and 2 sparkys all bonfide qualified traders and ive got further has anyone else had the lr and the cyl stat wired wrongly true none of them were WB engineers , is that my error

 

[davesparks]

If using a Worcester easycontrol for a system boiler then the boiler needs to have the optional diverter valve fitted and a seperate pipe from the hot water cylinder back to the boiler.

The easycontrol does not work with a Y plan system.

 

[Ziggie]

have you got a meter and skills to use it?

warning even with controls set off , there are live wires in the wiring centre.

I will assume the boiler is WB greenstar.

I have never worked on solar -so don’t know how this connects in.

the boiler is running because the SL core has voltage.


If the boiler is always on, then there is voltage on the sl wire when there should not be.
Switch off electric and don’t go near wire !

Try disconnecting the SL to the boiler - boiler should stop and pump should stop soon after. If it does not stop , then fault is with the boiler or wiring within it. (perhaps the SL terminal in the boiler is wired from the live feed )

I checked today that you need a gas safe to remove the cover to check the wiring but you can do a simple test from the wiring centre.


Normally the SL is on the connector which has the orange wire from the 3 port.There is another wire from the cylinder stat so don’t disconnect the wrong one.

If the SL connection is live , then there is a wiring problem or the controller is broken. Even if the controller is broken , the stats should not allow current through if they are turned down

any spark should be able to identify the source of the problem.

A question - assuming you have checked the wiring “ is there a wire between the HW off on the controller into the wiring centre with the grey wire from the 3 port”?

Hope this helps you and the electrician that visits.

I can supply wiring diagram etc but it won’t include solar.

 

[Ziggie]

Overnight had thoughts on what the problem might be.
No knowledge but lets do a flier......
Lets assume that the system was working before the solar system was installed?

The flier idea is " the supply from the solar system was put into the heating system either by placing the wire into the SL terminal in the boiler or into the terminal in the wiring centre where the cable that is connected to the SL terminal in the boiler."

Whats the evidence?

There are two sources of power :

• Mains
• Solar

There are 4 combinations.

• No power
• Power from both
• Mains Power only
• Solar Power only

What happens on each:

Power from both
Boiler running all the time whatever setting on controller
3 port valve working as expected (when select Heating - 3port moves to H etc)
Solar Power only
3 port will move to Hot Water ( default if no power on Grey/white wires)
Boiler will run all the time.
No Power
everything is off
Mains Power Only
The boiler should be off if the controller has neither heating or hot water selected.
The pump should switch off after about 5 minutes
The system should be working normally (thermostats etc).

So the question is "if you isolate the solar power (switch the supply off before the connection to the heating system)" , does everything work as expected?

What happens?

A rough wiring diagram would be useful.