noisy non return valve.

[Dan Masey]

I have a unvented system and have run a secondary return on the hot water due to the size of the property. I have a non return valve directly after the bronze pump that rattles and is causing a nuisance. Is there a diff type of double check valve i can use to stop this rattling?

 

[chris watkins]

What type have you installed Dan ? Spring loaded check or flap type.

 

[chris watkins]

I normally use this type.
But it must be installed in the horizontal or with the arrow pouting up.

 

[Mgrant]

Is it not just a single check valve you require?

 

[gassafe]

Those check valves always rattle, the swing valve above will remedy it & prolong pump life probably

 

[plumben]

ive found sometimes that no returnes can be noisy when there the spring type and they've jumped out of place, try replacing the valve like for like first or as above use the swing valve

 

[ShaunCorbs]

swing valve all the way less to go wrong

 

[Dan Masey]

I've installed a double check valve. Have no idea if it's spring loaded or no? Maybe I'll try and like for like swap and see what happens. I've never heard of the swing valve before?

 

[ShaunCorbs]

I've installed a double check valve. Have no idea if it's spring loaded or no? Maybe I'll try and like for like swap and see what happens. I've never heard of the swing valve before?

Wrong type mate Google swing valve and install one

 

[Dan Masey]

Ok I'll pick one up tomorrow from pipe centre. Any reason why it has to be installed horizontal? My NRV currently points down after my pump then into my megaflo.

 

[ShaunCorbs]

Ok I'll pick one up tomorrow from pipe centre. Any reason why it has to be installed horizontal? My NRV currently points down after my pump then into my megaflo.

So the flap closes but some have a spring on them and there ok horizontal

 

[rpm]

Swing valve need weight of water to close it fully?

 

[ShaunCorbs]

Swing valve need weight of water to close it fully?

Back flow closes/ the weight of the swing it fully

 

[rpm]

I put it up as I wasn`t sure that there would be enough water there not doing gas boilers.

 

[ShaunCorbs]

I put it up as I wasn`t sure that there would be enough water there not doing gas boilers.

Not a problem only stupid question is the one you don't ask

 

[Dan Masey]

But the pressure of the unvented cylinder will surely close it? It's basically another hot water outlet on the cylinder. I thought the NRV was to protect the pump?

 

[ShaunCorbs]

But the pressure of the unvented cylinder will surely close it? It's basically another hot water outlet on the cylinder. I thought the NRV was to protect the pump?

Will open one way but will shut if the water back flows

 

[rpm]

Not a problem only stupid question is the one you don't ask

Shouldn`t of put the ? but didn`t want to put a ! either, should of rewritten it.

 

[chris watkins]

But the pressure of the unvented cylinder will surely close it? It's basically another hot water outlet on the cylinder. I thought the NRV was to protect the pump?

Think about it Dan what pressure is there at the other end of the return away from the pump?

So long as the hot & cold are all balanced & the pump is running when any hot water drawn, then I am not convinced that a non-return is required but the MI's alway show. It is installed to stop cold water from the feed being drawn back up the return to the taps missing out the cylinder as it were.

When no water is being drawn then both sides of the check are at the same pressure but flow from the pump will push the gate open so water can circulate around the closed circuit.

 

[Dan Masey]

Thanks Chris. Makes sense when you look at like that. I'll get a new swing check valve today just to be on the safe side.