W-plan pump run on

[davidwf]

If I convert to Y plan do I need a mid position or 3 port valve.... I THOUGHT they were one and the same....they both have 3 ports!

 

[John.g]

You can get a (3 port) diverter valve that will give you CH or HW, you can also get a (3 port) mid position valve to give CH only, HW only, and CH&HW, thats why its called a mid position valve.

 

[davidwf]

hmmm...so, If I were to convert to Y plan presumably I need a mid position valve for my installation?

 

[John.g]

Convert from what?, a S plan which has separate 2 port valves for CH & HW or a W plan which has a 3 port Diverter valve as above but only gives CH or HW.

 

[davidwf]

convert from the existing W plan...
If I changed it to S plan, when both are satisfied there would be nowhere for the residual heat to circulate ....as mentioned, the bypass loop appears to be just that - a 15mm pipe around the pump which I am not sure IS a bypass loop as such
"only" CH or HW is fine as it is quite a small house and the HW requirement is low

 

[John.g]

convert from the existing W plan...
If I changed it to S plan, when both are satisfied there would be nowhere for the residual heat to circulate ....as mentioned, the bypass loop appears to be just that - a 15mm pipe around the pump which I am not sure IS a bypass loop as such
"only" CH or HW is fine as it is quite a small house and the HW requirement is low

You could go the conventionel way of installing a ABV between the boiler flow&return if converting to a S plan otherwise convert to a W system with a 3 port diverter valve.

 

[davidwf]

possibly..... just possibly.......
I suggested he turned the CH stat right down and turned the HW stat right up......popped over to the house this morning and found the rads were red hot.
Investigation found that the valve was not returning fully to the home position when the CH satisfied (W-plan remember)……there was no voltage across the motor so nothing could be holding it open
I undid the 2 screws that hold the backplate to the brass valve about 1/2 a turn and the assembly immediately fully opened which should of course close the CH circuit…….did them back up and operated it again and it was quite stiff and didnt return fully…..
I have put two small washers between the backplate and the brass valve to space it out a little bit and it now APPEARS to be working properly !.....hmmm
...and that was a brand new unused Honeywell V4044C1288/U 22mm 3 Port motorised diverter valve, sadly bought off a private seller on ebay so no guarantee, the backplate looks straight and there are no dents or anything anywhere

If it continues to work OK I will take that as a win 😀

 

[davidwf]

You could go the conventionel way of installing a ABV between the boiler flow&return if converting to a S plan otherwise convert to a W system with a 3 port diverter valve.

it already IS (and always has been) a W-plan system with motorised diverter valve..........

 

[davidwf]

pleased to report that it is still functioning correctly as per my findings......so much for buying expensive Honeywell !