Stuart Turner Monsoon Universal 4 bar twin - HUNTING

[woodfordma]

I have a Stuart Turner Monsoon Universal 4 bar twin negative head which feeds the house.

We had a bathroom installed in the loft. After a while the pump began hunting in the middle. Turning on for about 5 seconds and the turning off whilst there was not running water, apparent leaks or overflowing cisterns. The hunting then began to get closer and closer together (timewise).

We had the pump exchanged with a brand new one by Stuart Turner installations guy. For a few hours the hunting ceased but that evening it started again. It also seems to be becoming more frequent again.

At night the pump has to be switched off because the noise is so loud it is enough to wake everyone in the house and deeply upset our neighbours. The situation is so stressful as it is bad enough bothering oursleves but it also causing our neighbours distress and any help would be grately grately appreciated.

In summary as mentioned before, the pump is brand new so non return valves are obviously not the problem (neither is the pump). There are no dripping taps or overflowing cisterns. There are no apparent leaks in the pipework to the loft.

Please help!

Many thanks in advance!

ps I am going to try closing the outlet isolating valves tonight, but because the pump is brand new I doubt this is the problem and will confirm that water is being drawn. Is there any way of finding out where it is being drawn from if this is the case? (assuming no visible leaks or dripping taps / showers / loos etc)

 

[doitall]

Expansion vessel duff or lost it's pre-charge

Failing that, is the hot water on a secondary circuit.

Is a wc connected to the pump.

 

[woodfordma]

All the equipment is less than two years old and installed by BG. The expansion vessel looks as good as new and remains at around 2 bar (are we talking about the main expansion vessel).

There are two WCs connected but neither cistern looks to be overflowing.

Not sure what you mean by the hot water secondary unit but all hot water in the house is fed through this pump.

Thanks

Mark

 

[Phill Peck]

does the pipe out of the top of cylinder go vertically or horizontal?

is the connection for the pump taken in the correct place?

 

[doitall]

All the equipment is less than two years old and installed by BG. The expansion vessel looks as good as new and remains at around 2 bar (are we talking about the main expansion vessel).

There are two WCs connected but neither cistern looks to be overflowing.

Not sure what you mean by the hot water secondary unit but all hot water in the house is fed through this pump.

Thanks

Mark

How is the pump connected.

Is it a cold water booster, that also feeds the cylinder.

What is the main expansion vessel you mention.

Wc/ball valve should never be fed from a boosted supply.

Since you mention BG there's a very good chance it's not connected properly. Can you do an as fitted sketch please.

 

[woodfordma]

Thanks. Its very difficult for me as I am not a plumber. I may be able to take some pictures and send them otherwise I will explain very simply what I know.

The expansion vessel I refer to is prob 30cm diameter by 40cm height and sits next to the boiler.

The whole central heating system is located on the 2nd floor of the house (boiler, hot & cold water tank, controls, pump etc). The cold water tank (filled by mains pressure) supplies the pump (cold inlet) and the water from the hot water cylinder also supplies the pump (hot inlet). The pump is on the 2nd floor.

Cold water on the ground and 1st floor is fed by mains. Cold water on 2nd and attic comes from the cold water tank and is routed through the pump. Hot water comes from the hot water cylinder and is routed through the pump.

When wc is flushed on 2nd floor or attic the pump kicks in to feed the water on demand.

British Gas fitted the whole system in 2009. It all worked fine for over a year but after we did a loft conversion, which was plumbed in by our building contractor, the hunting began. I am happy to take some photos of the central heating system but would imagine it would be difficult to make out from a photo so I hope my simple description helps. Ideally having someone with plenty of experience in this field to take a look is the best way forward but various plumbers have been clueless (or unhelpful).

I hale from Bath but sadly I'm based in London now.

If I can be any more specific about anything I will try to be but I really am a layman.

Thanks

Mark

 

[tryitandsee]

My Universal pump keeps turning on and off, how can I fix this?
Check for any leaks in the system. Check the tap washers and pipe joints etc. Check the pre-charge pressure in pressure vessel, but to do this the pump must be switched off first and the pressure released from the system.

Taken straight from Stuart Turner web site.

Having taken my Universal pump out the other day to replace the start capacitor, I have had a very small leak on the flexible pipe connections. The so called easy fix/ push in plastic bit on the end of the pump hose. It was very difficult to tell it was leaking as no obvious signs. The only way I found it was toilet tissue strategically placed underneath pump and observed the next day after use.

When these push in connections are disturbed the o ring/cramp can be distorted or the connecting pipes not pushed all the way home.

What I'm trying to say is, air may be leaking from there, making the pump start. Make sure all pipe work to pump is fitting snugly.

 

[tryitandsee]

Oh and also, although you can pump the WC, it's not the best thing to happen when you flush late at night and the pump kicks in. Plumb it back to the mains if possible.

 

[doitall]

Tell us about the loft extension and exactly what they did.

The pressure vessel pre-charge is the most likely problem, other than a system design fault, and connecting Wc's to boosted supplies.

When you flush the toilet the ballvalve fills slower than the pump can deliver so it will cycle on and off until the valve shuts off.

Can you isolate the extension and try it.

nothing to do with the heating or any red vessels, we should only interested in Blue ones, and maybe an SS one on the pump

 

[woodfordma]

Wow. You really sound like experts and I wish I had a clue what you are talking about. Well thats maybe a little harsh on myself as I do understand a little.

I totally understand tryitansee's comment which makes absolute sense. We had a sunstantial leak (o ring must have gone) coming from the flexihose connected to the pump and had to have it replaced. I think from memory the hunting began after this flexihose was replaced by a plumber. However since then a stuart turner installer cam and replaced the pump so would have had to reattach the flexi hoses. The hunting stopped for a short while but came back that evenign as I said in my first posting. How can I make sure these flexi hoses are absoloutely tight and not letting air excape.

Doitall's suggestion about the pressure vessel pre charge would then presumably link into this with the problems being the flexi hoses. I guess what I need to do is make sure the flexi hoses are air tight and recharge the vessel but unfortunately I have absolutely no idea how to do that and do not want to flood the house.

In regards to the loft, we fitted a bathroom on the 2nd floor and loft. A shower bath and loo and sink on the 2nd floor and shower, loo and sink in the loft. There are no visible leaks as I mentioned before. There are also radiators but of course these are separate from the pump.

With the loos being in the loft, was there anyway of them being mains fed. They probably should have been but that opportunity has been and gone now and after your very good advice I know for future reference! Although I am determined to get a magaflow at all cost if I move again!

Not sure about the ball valve comment as the pump goes off continuously well after the cistern has been filled. The thing is that this problem begun a little time after the loft was finished and got worse and worse so is likely to be the pressure issue as you suggested. I just need to know to to sort it out.

Thanks so much for your help!!

 

[tryitandsee]

Doitall, can a thermostatic/mixer valve on a shower let water by even with the thermostatic valve being visually shut.
Thinking out loud I know, but could it allow water to be pumped back the wrong way, into the header tank! making the pump hunt.

 

[picasso]

I think I would start by looking at where the pumped hot meets the mains cold, kitchen sink, washing machine connections ect, it could be the pump is pressurising the mains water supply due to a sticking nrv or you have a leak on the hot water supply under the floor.

 

[tryitandsee]

www.stuart-turner.co.uk/where-to-buy/spares-finder/46294/17

Perhaps the pressure switch got wet when you had the leak.
These pumps are so well made, that I would question whether the engineer who replaced the pump, changed it for a new one. Parts are easily obtained and repairs are normally carried out. Perhaps the pressure switch was over looked! or a loose connection. I'm guessing now but another question to be looked into.
Good luck.

 

[woodfordma]

It was definately a brand new pump in a new box. I watched him install it.

There are no hot pipes where a leak would not be visible. Underfloor heating but then that has nothing to do with the pump.

If the pre charge vessel loses its charge due to air escaping somewhere, and that sounds to be the most common cause of hunting then I suspect its that.

Tryitansee, the pump has inbuilt non return valves so is it possible for water to be pumped back the wrong way and cause the pump to hunt.

I think I need to check if air is escaping somewhere causing the precharge to lose its pressure. Just have no clue how to do it and how to pre charge the vessel.

 

[doitall]

Can you isolate the WC's on the top floor and try it.

While you at it you could turn the mains supply off, although mains cold/boosted hot combination most be limited almost to the kitchen sink.

I mention a secondary circuit.

This is a loop of hot water with a bronze pump circulating it around to house.

The way thread is going, I'm not so certain it's the expansion vessel.

it's sounding more like an installation error or WC's.