Help!!!

[hillsborough]

i have a glow worm boiler, graundfos pump and honeywell 3 way valve, that i have taken apart and seem to work correctley,
If i have just c/h on all rads get hot , if just h/w thats fine but if the water comes on when the c/h is already on the downstairs rads go cold until the water is up to temperature .
Any ideas!!!

 

[Agile]

There are two types of three port valves!

One is a mid position with three different positions and another is a two position. You might have either?

Alternatively it may be either type but have been wired to give priority to the hot water.

I assume that it has always behaved this way ? If not then a fault has occured, perhaps on the microswitches in the valve.

Tony Glazier

 

[JohnD]

One other possibility (hopefully rare). I used to have a house with an undersized boiler. In very cold weather, it hardly had enough power to keep the house cool. If you ran a bath, the extra drain on the boiler meant you actually felt the house go cold.

As it is your downstairs rads going cold it might be that the power of the pump is sending the circulation mostly round the cylinder, which is a short, wide pipe run, so it is taking the easy route instead of making its way down that long complex route of the downstairs rads.
- is your pump on highest speed?
- does the pump/cylinder/return pipework all in 22mm or is it throttled back with a short section of 15 to stop the cylinder hogging all the heat?

If the upstairs rads are fully hot, you might try turniung them off, if that fixes it you could rebalance the radiators to encourage downstairs flow.

 

[hillsborough]

i have a glow worm boiler, graundfos pump and honeywell 3 way valve, that i have taken apart and seem to work correctley,
If i have just c/h on all rads get hot , if just h/w thats fine but if the water comes on when the c/h is already on the downstairs rads go cold until the water is up to temperature .
Any ideas!!!

The pump is running at full tilt (3).
The pipe work is 22mm all the way but the problem has only started in the last week or so .no work done on water system in over 2 years apart from a service 8 months ago.

 

[scatmanjohn]

The ball in the valve could be swollen which would restrict the flow through the valve when in mid position.
A new valve should fix it or if your handy with the tools you can just replace the ball.

 

[hillsborough]

tony

the 3 way valve is the mid position type. when you say it could be wired up to favour hw, how would i change it to favour ch?