Stuart Turner Monsoon Universal 4 bar twin - HUNTING

[tryitandsee]

I admire your have a go attitude to all this.

I reckon the head of water in the hot water pipe work above and away from the pump is falling back/weeping very slightly through the non return valve, the pressure switch being very sensitive activates pump.

Give Stuart Turner Technical a ring. When I phoned them with my problem they were very helpful and certainly knew their pumps.

Call the Pump Assist team on: 0844 98 000 97

 

[woodfordma]

Thanks tryitandsee. Called ST. They said that if the hot outlet is isolated is turned off and the hunting stops then it is definitely not the pump. It is caused by a drop in pressure on the hot causing the pump to cycle. The pressure has to drop to one bar for the pump to cycle therefore since the pump is going every 15 minutes (requiring the pressure to drop from 4.5 bar to 1 bar) it would either be a significant leak (ie detectable) or an internal leak. So internal leak it is.

So it looks like it is most likely one of the ruddy shower mixers. Does resolving this requiring making a mess of the shower tiles and wall?? Arrgghhh

 

[tryitandsee]

Nearly getting there

Doitall or Agile. can the introduction of non return valves on the showers help in this situation, if the shower mixers are the problem?

 

[doitall]

Nearly getting there

Doitall or Agile. can the introduction of non return valves on the showers help in this situation, if the shower mixers are the problem?

Yes but good shower valves have them inbuilt, so should technically only need to remove the valve and change/clean them.

If there's an internal leak the mains or TOILET is the only options, fitting a double check valve on the incoming mains would test the theory, as would turning the damn stopcock off.

If there's a back flow the mains will pressurize and the hunting should stop.

If it doesn't a TOILET is leaking, or you have a leak.

Rocket science over 10 pages, and I'm still beating me head on the wall.

And the mixer valves should be in the normal working position.

 

[woodfordma]

It definitely isnt a toilet as this is a hot side problem. The pump's hunting is caused by the hot side.

I spoke to Grohe (shower mixer) and their technical support think the problem is supplying some parts of the house with mains cold and some parts with pumped cold but always in conjunction with pumped hot.

Would a non return valve really work on the shower. If there was crossing over from the hot to cold, casuing a drop in pressure, wouldnt this drop in pressure continue to 'demand' from the pump regardless of whether there is a non return valve or not.

Surely if the pump does not hunt when the hot side is isolated, the hunting doesnt have anything to do with backflow on mains?

If I manage to find a stop cock out on the street (where the mains reaches my water meter) what do you want me to do / test if I switch this off?

 

[tryitandsee]

Worth trying, we've suggested everything else

 

[doitall]

The backflow would be because the hot pressure is higher than the mains.

The non-return valve stop any backflow, if you are talking 3-4bar pumps I would fit double check valves instead of single check valves.

But you still haven't proved the problem. How difficult can it be to turn everything off for a day.

 

[woodfordma]

Not hard.

So do you want me to turn off the mains and leave everything else as is? (pump on (neither hot nor cold isolated), mixers in normal position and kitchen tap closed?)

I can do this before I go to work tomorrow.

What do I check when I get home. Just whether the hunting has stopped?

What would the result tell us?

 

[doitall]

All you need to do is turn the mains off, 2-3 hours should be enough depending on the backflow and the pressure differential between the mains and pump, assuming you have one.

You should notice the intervals between hunting getting further apart quite quickly.

Obviously you can't use any water during the test.

From your point of view it would be best if it is proven to be a backflow, as it localizes the problem.

If the hunting has stopped you have a backflow.

 

[tryitandsee]

Are we confident the mains stop cock shuts off completely. What about that trickle earlier, was that the stop cock NOT being totally shut!

 

[woodfordma]

I shut it finger tight, but firm enough for it to be properly closed. I was going to look out on the street for the stopcock at my water meter and try that one too.

 

[doitall]

Are we confident the mains stop cock shuts off completely. What about that trickle earlier, was that the stop cock NOT being totally shut!

Hopefully yes, it isn't that old I gather, otherwise turn it off out side as well, although that could affect the test duration.

my first job would be a double check valve above the stopcock if the test failed. and re-do the test.

 

[woodfordma]

Yes. Its all new. Even the pipe leading from the mains on the street coming into the house was replaced.

I will turn the stopcock off in the street first and test for the same result with the kitchen tap.

If I have to go putting in any valves then thats probably beyond me!

 

[doitall]

Yes. Its all new. Even the pipe leading from the mains on the street coming into the house was replaced.

I will turn the stopcock off in the street first and test for the same result with the kitchen tap.

If I have to go putting in any valves then thats probably beyond me!

Why the test proves nothing.

The pump is loosing pressure, if the stopcock is turned off, either the hunting stops or the problem is elsewhere.

Prove the problem first.

 

[woodfordma]

Morning all

I was able to turn the mains off at the valve in the street as well as in the house (turned off around 7pm).

I did this and didnt use any water until about 10pm. The hunting did not stop as after I had finished watching a film I heard the pump.

Because I was watching a film I could not tell you the frequency of the hunting.

The difficult thing is that I think the frequency of the hunting does vary. For example when in the house at the weekends, I do not hear it as frequently as every 15 minutes but if I am anywhere in the house it can be easy to miss. I do think it varys though depending on the water usage in the house and seems to be more frequent in the evenings (perhaps when there is the most water usage).

I have isolated all three loos before and the hunting continued so I'm not convinced of that. I am not convinced of a leak either as it has been going on for about 7 months and given the drop in pressure of 4 to 1 bar every 15 minutes the leak would be visible.

I definitely do think it is something to do with how the pumped hot and mains cold are plumbed in and interacting, especially with the mixer taps and showers.