A couple of months ago I fitted a thermostatic mixer for a friend to
provide warm water to an outside tap for dog showering purposes. I was a
little uneasy about it working well with a gravity HW system and mains cold
but the manufacturer assured me that it would work.

Indeed, it did work fine until recently when it started to exhibit weird
behaviour. Now when you turn on the tap, nothing comes out. No water at
all, neither hot, cold or warm. If you leave the tap open for a few
minutes, the water starts flowing and it seems to work fine. I tried
tapping on the valve to see if maybe this would free a stuck non-return
valve but it had no effect.

This is repeated on a daily basis. Can anyone explain this behaviour?

Tim

--
Please don't feed the trolls

Sounds like there is air in the pipe somewhere to me.
Brian

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"Tim+" wrote in message
...
A couple of months ago I fitted a thermostatic mixer for a friend to
provide warm water to an outside tap for dog showering purposes. I was a
little uneasy about it working well with a gravity HW system and mains
cold
but the manufacturer assured me that it would work.

Indeed, it did work fine until recently when it started to exhibit weird
behaviour. Now when you turn on the tap, nothing comes out. No water at
all, neither hot, cold or warm. If you leave the tap open for a few
minutes, the water starts flowing and it seems to work fine. I tried
tapping on the valve to see if maybe this would free a stuck non-return
valve but it had no effect.

This is repeated on a daily basis. Can anyone explain this behaviour?

Tim

--
Please don't feed the trolls

PS probably in a long horizontal run with a sag in the middle.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Tim+" wrote in message
...
A couple of months ago I fitted a thermostatic mixer for a friend to
provide warm water to an outside tap for dog showering purposes. I was a
little uneasy about it working well with a gravity HW system and mains
cold
but the manufacturer assured me that it would work.

Indeed, it did work fine until recently when it started to exhibit weird
behaviour. Now when you turn on the tap, nothing comes out. No water at
all, neither hot, cold or warm. If you leave the tap open for a few
minutes, the water starts flowing and it seems to work fine. I tried
tapping on the valve to see if maybe this would free a stuck non-return
valve but it had no effect.

This is repeated on a daily basis. Can anyone explain this behaviour?

Tim

--
Please don't feed the trolls

Which there isnt. Whatever the problem is, it isnt an airlock. The
supply to the taps on the inside work fine.

Brian Gaff wrote:
PS probably in a long horizontal run with a sag in the middle.
Brian



--
Please don't feed the trolls

It happens that Tim+ formulated :
Which there isnt. Whatever the problem is, it isnt an airlock. The
supply to the taps on the inside work fine.

I agree and suggest it is the none return valve closing and sticking
closed - maybe due to limescale build up. Take is off, strip and clean
it out.

Harry Bloomfield wrote:
It happens that Tim+ formulated :
Which there isnt. Whatever the problem is, it isnt an airlock. The
supply to the taps on the inside work fine.

I agree and suggest it is the none return valve closing and sticking
closed - maybe due to limescale build up. Take is off, strip and clean
it out.


Its barely two months old and we live in a soft water area. I suspect
your right about it sticking though.

Tim

--
Please don't feed the trolls