Blending valve fault?

[bennettp23]

Hi,

We have a thermal store and a powermax blending valve.

The hot water has become a trickle (although it is still hot if I adjust the valve). The CH etc works fine. I believe it is a P757 blending valve, do you think this would be the issue? Cold water pressure if fine.

It's £100 so I want to be sure before I buy it . Or is there some maintenance I could do?

Thanks,

Paul.

Edit:

Searched again and found references to descaling the valve. If I try this how long should I leave it?

Also, while I have it off (so to say ), can I descale the coil in the thermal store? If so, how would I go about it? Just pour some desclaler down the pipe going into the store?

ch

• bennettp23
• 30 May 2013
• 3

Silver cylinder

 

[Gas2Air]

If the pressure at the hot tap is a trickle it will be inline strainer/pressure reducing valve.

 

[bennettp23]

If the pressure at the hot tap is a trickle it will be inline strainer/pressure reducing valve.

Hi, thanks for the reply. Where is that?

 

[Gas2Air]

Underneath your blending valve.

 

[bennettp23]

Underneath your blending valve.

Is it possible to clean them??


I am descalling the blender valve as we speak

 

[Gas2Air]

Yes you can take out the strainer small nut after the reducing valve. The valve itself isn't serviceable though. Make sure you use ptfe on the strainer when refitting.

 

[bennettp23]

Yes you can take out the strainer small nut after the reducing valve. The valve itself isn't serviceable though. Make sure you use ptfe on the strainer when refitting.

Is the PRV adjustable or is it factory set?

 

[Gas2Air]

Factory set to 3 bar. I suspect it may well be the fault but try checking the strainer first. Be brave and disconnect the pipework after it and have someone turn on the mains, to check pressure.

 

[bennettp23]

Well, I soaked the valve in acid (Vinegar) for a few hours. But problem not solved.

When I turn the valve to the furthest cold, then the flow from the taps is good. Then says to me that the PRV is fine. I also poored some lliquid down the coil outlet and it flowed through fine so I guess cloggin of that is not the issue.

I guess it is time to bite the bullet and spend £120 on a new P757 valve and hope that fixes it!

 

[bennettp23]

Just to close the thread.

Blender valve changed, all working great again!