Non return valve on unvented

gingalig · Oct 10, 2019

Hi, thanks in advance for any advice, I've come to change a manifold for the ufh, I have noticed a non return valve on the main dhw outlet on the unvented cylinder
Is this acceptable ?
[automerge]1570704464[/automerge]

gingalig said:
Hi, thanks in advance for any advice, I've come to change a manifold for the ufh, I have noticed a non return valve on the main dhw outlet on the unvented cylinder
Is this acceptable ?

My thoughts are no it's not.

Stigster · Oct 10, 2019

There's no safety reason why it shouldn't be there and is no different to having non-return valves anywhere else on the hot distribution side of the system. Do you have a secondary return (pumped circuit) on your system?

gingalig · Oct 10, 2019

Stigster said:
There's no safety reason why it shouldn't be there and is no different to having non-return valves anywhere else on the hot distribution side of the system. Do you have a secondary return (pumped circuit) on your system?

No there isn't. Thanks for the reply.

Stigster · Oct 10, 2019

Unless you can find a decent explanation for why it's there I don't think it's necessary but at the same time it's not really doing any harm either.

It would be interesting to know the reasoning behind it being fitted there though.

ShaunCorbs · Oct 10, 2019

Backflowing though a shower mixer or tap prob

Stigster · Oct 10, 2019

ShaunCorbs said:
Backflowing though a shower mixer or tap prob

So they went for a "whole system" approach rather than at point of use I suppose. The shower feeds may have been inaccessible which would make sense of that valve's position.

snowhead · Oct 10, 2019

Stigster said:
So they went for a "whole system" approach rather than at point of use I suppose. The shower feeds may have been inaccessible which would make sense of that valve's position.

And at least it's easilly found and accessible if it fails.

Jim Goodenough · Nov 27, 2019

gingalig said:
Is this acceptable ?

I'd say if there's not a backflow issue anywhere remove it as it will be decreasing flow.

AWheating · Dec 1, 2019

Probably a tmv/ mixing valve causing an issue. Is your cold water alot better than your hot? Pressure wise?

Many tmv's have problems if theres a different between the hot and cold.

Non return valve on unvented

gingalig

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