worcester greenstar ri Y-Plan

[davek]

Hi all
been called out to a boiler replacement with the above boiler. The problem is it wont run on heating only. have check wiring and all I can spot is that from controller there is no wire going from HW OFF to cylinder stat terminal 2 and grey on valve. Any thoughts and no spare cores in original wiring.
regards
Dave

 

[Richard Burns]

Possibly a jammed three port valve or the microswitches have failed, see if the valve is turning fully open.

 

[davek]

spoke to Worcester apparently the lp on the boiler need run direct to pump so will give it a try tomorrow,
cheers
Dave

 

[davlec]

Hi.... On a y-plan you need the cable from the hw off connection on the programmer to the grey on the valve and number 2 on the cylinder stat to power the valve into heating only... You will not get it to work correctly in another way