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Discuss Help required to identify a valve on Hot Water Draw-off in the Plumbing Jobs | The Job-board area at PlumbersForums.net

call a local engineer and get rid of BG
 
Hello All,

Further to my previous message:

Looking more closely [at the photo] - the Pressure Reducing Valve setting Dial - does it look like it is already set at approaching either `5` or `6` ?

Chris
 
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Hello All,

Further to my previous message:

Looking more closely [at the photo] - the Pressure Reducing Valve setting Dial - does it look like it is already set at approaching either `5` or `6` ?

Chris

Here goes - frankly its got more less chance of being true that one of Donald Trumps tweets...
How about:
Symptom is severely reduced flow. Possibly strainer on incoming main partially blocked and potentially that in the control block too. So, instead of cleaning out and descaling the filters they've simply upped the set point on the PRVs so it 'improves'. That however gives too much initial flow (especially if the pressure vessel has failed too) so the whack in the PRV on the outlet! Told you it was nuts! :rolleyes:

Of course the problem there would be the pressure relief valve in the control block. That normally starts weeping. As we haven't seen the tundish we have no idea one way or other its state. Not being a betting man, I'd put my 10p on it being scaled.

IF that's the case then its a new block, sort vessel, sort incoming main filter & rip out the abomination on the OP.

Chris. It can't go over pressure for the cylinder as you have two protections.

OP - I'm already sure of this answer, but when was this system last serviced? I can see the optimistic emojis flooding in :D
 
Hi there,

TBH, I'm not sure it has been serviced (apart from the general annual service that we get from BG but that seems to be concentrated on the boiler in the garage) - should I be asking them to service the megaflo at the same time?

Re the setting on the PRV, it has been turned down as the water is now off, as it was leaking so the value currently showing on it is not what is was at pre-removal.

The Tundish appears to be fine - please see pics

Also, have not been aware of any dripping into the tundish.

Thanks
Steve
20181024_210331.jpg
20181024_210307.jpg
 
Here goes - frankly its got more less chance of being true that one of Donald Trumps tweets...
How about:
Symptom is severely reduced flow. Possibly strainer on incoming main partially blocked and potentially that in the control block too. So, instead of cleaning out and descaling the filters they've simply upped the set point on the PRVs so it 'improves'. That however gives too much initial flow (especially if the pressure vessel has failed too) so the whack in the PRV on the outlet! Told you it was nuts! :rolleyes:

Of course the problem there would be the pressure relief valve in the control block. That normally starts weeping. As we haven't seen the tundish we have no idea one way or other its state. Not being a betting man, I'd put my 10p on it being scaled.

IF that's the case then its a new block, sort vessel, sort incoming main filter & rip out the abomination on the OP.

Chris. It can't go over pressure for the cylinder as you have two protections.

OP - I'm already sure of this answer, but when was this system last serviced? I can see the optimistic emojis flooding in :D


Hello again YorkshireDave,

What a good `Diagnosis` very well described - I was in total agreement with what you explained until I posted this message and saw that the OP / Steve had posted photos of the Tundish.

However as You pointed out probably the most frequent cause of loss of Hot Water volume to the outlets from a Megaflow is a blocked / scaled inlet filter - it should have been the first `Check` carried out.

I worded my comment about the inlet pressure to the Unvented Cylinder very badly - I was being rushed by `She who must be obeyed` to sit down for Dinner.

I was trying to think along the lines of - is the inlet pressure very close to the specified `Maximum Inlet Pressure` and are there occasions when without the OP knowing the PRV is discharging and when the Cylinder pressure is being `relieved` that affects the Hot Water draw off pressure & volume ?

I then realised that the PRV would not be releasing enough water / pressure to affect the Hot Water pressure / volume.



Chris
 
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Something has been letting by into the tundish - but not for long looking at it. No evidence of long term discharge which makes it all the more puzzling tbh...

With no servicing having been carried out, that'd still be my first port of call - a proper and extensive service. At that point I'd review whole system performance and change controls to suit. Still got my 10p on removing that redundant PRV... possible another too.

Steve. You need to get an experienced G3 engineer on to this. If you check your BG contract, I'd be very very surprised if your UVC is covered. Personally, I'd look for a suitable local engineer and get it done properly and annually so you and your family are safe into the future.
 
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Something has been letting by into the tundish - but not for long looking at it. No evidence of long term discharge which makes it all the more puzzling tbh...

With no servicing having been carried out, that'd still be my first port of call - a proper and extensive service. At that point I'd review whole system performance and change controls to suit. Still got my 10p on removing that redundant PRV... possible another too.

Steve. You need to get an experienced G3 engineer on to this. If you check your BG contract, I'd be very very surprised if your UVC is covered. Personally, I'd look for a suitable local engineer and get it done properly and annually so you and your family are safe into the future.
I think this conversation has been going on long enough in an open forum boys and girls if there is any on here.
 
We do have 1 on the inlet also - that's the one that he is going to replace tomorrow (as he had to order the part) - just need to have a night off from hot water - oh well, at least it gives me a reason to use my gym membership tonight (for the 1st time in about 2 years) lol

One other question, would it be better to ask him to replace the 'unknown' one with another of the same type to save any potential future issues?View attachment 35071
NO
 
The only thing I can think of that your builder / plumber has done when he built it is teed off for the balanced colds before the pressure reducing valve

Which has been causing problems with the cold overpowering the hot eg hot tap running cold on mixed, so they've put another reducing valve before the tee off

Best thing you can do is ask for a more experienced engineer to come out and have a look as your not happy

Also any parts they replace will have to be from the manufacturer to keep your cylinder warranty eg the black mono / control block one megaflow


Will leave this thread open for now but I'm keeping my eye on it
 
That engineer may be qualified but is not very good.
That valve is a pressure reducing valve. If it’s on the Domestic hotwater outlet then it’s been installed in the wrong place. The engineer may be right that it needs taking out and just pipe out in.
HOWEVER....He needs to have a look at the manufacturer’s instructions and replace and parts with genuine parts meant for that cylinder.
They need to be replaced in the correct order and according to G3 regulations!
 

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