Stuart Turner Monsoon Universal 4 bar twin - HUNTING

[Agile]

Tony

On our first floor bathroom we have two basin mixer taps and a shower mixer. When I have the taps / shower on but all the way over to the cold side the pump does not come on and it is fed by mains. If I mix in some hot obviously the pump kicks in. This must mean that the pumped hot is mixed with mains cold?

Many thanks

Mark

It seems that the mixer is leaking pumped hot back into the mains!

This was suggested towards the beginning.

As I said, mains and pumped should not be feeding the same taps!

BG should have known that and should rectify the problem!

It could be made to work by fitting a double check valve on the feed to each cold tap/shower.

Tony Glazier

 

[woodfordma]

Hi Doitall

I'm not sure if I have been all that helpful with my descriptions. And I didnt want to bore everyone with every single little change (which may have significance).

We bought the house as a shell and there was no CH. British Gas installed the CH system. We then stripped the house down and rennovated it with everything being new. In the kitchen the tap has a hot and cold. Hot fed by pump / cold. There is a boiling water tap (which fills with cold) and a dishwasher that uses cold.

First floor bathroom has two mixer taps and shower mixer and wc. This is where pumped hot must be mixed with cold mains witht the mixer taps.

2nd floor (where pump and CH system is located). Basin with hot and cold tap (both fed by pump), wc (pump), bath hot and cold tap (fed by pump), shower with mixer (fed by pump) and...

a washing machine (fed by pump). The washing machine is pump fed (presumably by pumped hot and cold?), although hunting conintues whether washing machine is on or off.

Lastly all pipework to the loft is brand new and there is a wc, basin with hot and cold and shower mixer all fed by the pump.

Hot sure if this helps to clarify anything in your minds?

 

[woodfordma]

British Gas did it right. I added mixer taps later on and the plumbers during the rennovation are the ones who got it wrong. If I can somehow confirm this is definitely the problem I can get the double check valve installed. Is there any way of confirming that this is defeinitely the problem?

Thanks Tony

 

[woodfordma]

sorry. I saw my typo error.

The kitchen tap has a hot and a cold tap. Hot is fed by the pump and the cold is fed by the mains. Just to clarify as I dont want to confuse everyone!

Thanks

 

[doitall]

Until you do the test I'll leave you with the boiler repair specialist.

 

[woodfordma]

Hi Doitall,

Id I managed to get access to the cold water storage tank, what would you use to test for a drop in the level of the water in the tank. As the tank is very large and the leak is very small, presumably the change in level would be virtually undetectable over one night. What do you reckon?

Thanks

M

 

[Agile]

British Gas did it right. I added mixer taps later on and the plumbers during the rennovation are the ones who got it wrong. If I can somehow confirm this is definitely the problem I can get the double check valve installed. Is there any way of confirming that this is defeinitely the problem?

Thanks Tony

I am happy that you have confirmed the problem.

Have you only just noticed that putting the mixer to the CW position stops the pump cycling? Didn't that make you run naked into the street shouting "Eureka"?

In forensic examinations like this its essential to do everything carefully and to report exactly the findings!

You only need the double check valve in the mains cold feed to the mixer.

Tony

 

[Agile]

Until you do the test I'll leave you with the boiler repair specialist.

He is in good hands here!

Even boiler repair specialists get the "while you are here can you look at....."

 

[Agile]

Until you do the test I'll leave you with the boiler repair specialist.

He is in good hands here!

Even boiler repair specialists get the "while you are here can you look at....."

 

[woodfordma]

Thanks Tony

I'm not a plumber, although after this feed I feel a little closer to becoming one, but I'm afraid I didn't realise that would be the cause. Is there any test to confirm this is the case? (to be certain before I forge ahead?)

I wonder why the hunting did not start immediately after the rennovation and instead only started a month or two after?

I suppose that if it is not correct to mix hot pumped with cold mains on mixers then there is no harm in fitting double check valves, but I dont really want to risk causing any damage to the shower if it is not neccessary.

Thanks

 

[doitall]

I am happy that you have confirmed the problem.

Have you only just noticed that putting the mixer to the CW position stops the pump cycling? Didn't that make you run naked into the street shouting "Eureka"?

In forensic examinations like this its essential to do everything carefully and to report exactly the findings!

Tony

Doesn't prove a thing, other than the hot is pump fed and the cold is mains.

I would expect the pump to stop if you did draw hot water.

 

[Agile]

OP.

If you shut off the mains water and open tap again and put the mixer control into the middle position and run the pump for a few hours you might feel the cold feed pipe to the mixer is getting hot.

But the amount of water flowing may be small and the hot water may be cooling in the pipes so it may not be a very scientific test.

Surely if the problem goes away when you move the valve, does that not convince you?

The problem is caused by slight leakage through the valves as a result of seals leaking when there is unexpected differential pressure between hot and cold.

You and others should always explain the whole story. There was I and probably others thinking this was another BG mess up.

I would always fit non return valves in feeds to mixer valves. Most of the instructions ask for them. Even if they dont then good practice means fitting them.

Tony

 

[Agile]

I would expect the pump to stop if you did draw hot water.

My expectation would be that the pump would run if you draw hot water!

 

[woodfordma]

Hi Tony

Just to clarify incase there is a misunderstanding. I meant that when I open the taps all the way to the cold position and run the water the pump does not come on, rather than moving the taps all the way to the cold but not running water. When running the water I move the tap slightly away from the cold the pump begins to run (just showing that the pump is feeding hot and mains is feeding cold).

So I can test your theory tonight that if I leave all the mixers all the way on the cold side (but not running) the hunting will stop? I'm not sure if that will work thought because I tend to leave the taps in the cold position anyway. If the pump does not stop hunting does that necessarlily rule out this hypothesis?

Thanks

Mark

 

[doitall]

Before the thread goes completely to the dogs.

You isolated the hot supply to the pump and the hunting stopped.

That tells you several things.

The hot may be back flowing into the mains.

The non return valve in the pump hot is not holding.

You have a leak.

A pipe has been corrected wrong.

If you turn the incoming mains stopcock off, eventually the mains will reach the pump pressure and any backup would be neutralized, and the hunting will stop.

Of course every time you open a tap or flush the loo you have to start again.

For Tony's benefit, the Hunting happens when all the valves are shut, so technically no water should get through the valves/taps.