pressure reducing valve?

[Mike Jackson]

Most combi manufacturers require them to be fitted if a DC valve is fitted.

 

[dancinplumba]

i use .5 lt ones

 

[diamondgas]

I didn't get the heads up on this till today .... So my grey matter didn't let me down .... if you're right kay-jay 🙂

 

[zeebeedee]

Diamond an expansion vessel is not required on a cold water main?

I hear certain boiler manufacturers are voiding warrantys when these are not fitted when a water meter is present, apparently it's causing wear and tear on boiler parts when the hot tap is closed and there is nowhere for it to go, ie non return valve on meter leaves it bouncing around the boiler.

 

[zeebeedee]

No one else heard this?

 

[diamondgas]

No one else heard this?

I think there's the potential for any of the water side gaskets to pop on the boiler ... if the expansion is so much that it takes the pressure in the domestic pipework too high?

 

[Mike Jackson]

It's in the MIs for some boilers now.

Fron the Ideal Logic instructions

important. Provision must be made to accomodate the expansion
of DHW contained within the appliance. If the DHW inlet contains a
back flow prevention device or non-return valve, e.g. a water meter,
then a mini expansion vessel should be fitted between the device and
the boiler in the cold inlet pipe.

Worcester also specify one in their instructions if a check valve is fitted, which means that you must fit one if there is a water meter.

Atag require one on all installations.

 

[Nostrum]

Is it still going!? :rolleyes4:

I think there is a bit of confusion regarding water trapped in a heat exchanger which will expand at a much higher rate than water in distribution pipework brought into a house from 10oC and warmed to 21oC room temperature.

I've looked through WRAS and I didn't see anything stating an EV was required after a pressure reducing valve on the incoming main. Personally I think it is an insignificant risk but thats me.

On a boiler after a check valve is a completely different matter and I fit one every time regardless now.