Help required to identify a valve on Hot Water Draw-off

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Steve-Scotland

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Hi there,

Hoping someone on here could assist with a query I have regarding a valve on our hot water draw-off from our Megaflo system.

Have called out British Gas Homecare engineer as hot water pressure has decreased on all taps/baths/showers to the point that it takes ages to fill bath/sinks or (mixer) shower is running tepid.

Long story short, he is going to replace a large pressure relief valve but as part of his investigation he noticed another valve on our 'hot water draw-off'.
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He didn't know what it was (thought it looked like either another PRV or a Mixer valve) but couldn't understand why this would be on the hot water draw-off - He called a couple of guys who could not identify it or its purpose.

He removed it to check it and it appeared clear, but when he to put it back in place, it started leaking when the cold water infill was turned back on.

He has said that when the other PRV is being replaced (tomorrow), he will take the leaking valve out and replace with a piece of pipe.

I'm looking for help to identify what it is, and would it be safe to remove it and replace with pipe (I'm thinking it must have been put in for a reason)?

Any help that anyone can provide would be greatly appreciated.

Many thanks

Steve

PS If it helps, he said there appears to be 3 pressure relief valves on the system - 1 at the main stopcock into the property, 1 big one on the Megaflo (which is the one he is going to replace), and this possible one on the draw-off.
 
Hi there,

Thanks for replying - The guy was great enough, and as he wasn't working on the cylinder as such (just the pipe-work running off it), I didn't think it was an issue (however I have absolutely zero experience with these things so really appreciate your assistance). I don't want to annoy/upset the guy who is coming back tomorrow, would calling BG back to request an unvented engineer do that?

Thanks again

Steve
 
Doesn't matter if it upsets anyone.
They should have sent a G3 in the first place.
You're paying them for a service and with unvented you really need to know what you're doing and it is a requirement for the engineer to have a G3 ticket, just like a gas man needs to be gas safe.
The guy didn't know what it was so was just going to remove it and join the pipes up? That's appalling, don't let him near it if he comes back.
 
Hi Steve-Sc0tland, as said above by HARVEST FIELD.
Ring BG for an Engineer on unvented hot water cylinder to get things sorted.
 
Hi,

Thanks - I'm now looking around the gas-safe register to get an engineer out that is authorised to work on unvented cylinders - unless there are any plumbers on here that are ticketed and are able to attend in Central Scotland? Also, any idea what the cost would be(I know thats a pretty dumb question as it would depend on whats wrong and how to fix, but was looking for ballpark on callout charge etc)

Thanks

Steve
 
Steve-Scotland said:
Hi there,

Thanks for replying - The guy was great enough, and as he wasn't working on the cylinder as such (just the pipe-work running off it), I didn't think it was an issue (however I have absolutely zero experience with these things so really appreciate your assistance). I don't want to annoy/upset the guy who is coming back tomorrow, would calling BG back to request an unvented engineer do that?

Thanks again

Steve
Click to expand...
Shouldn’t annoy anyone. He maybe G3 registered but inexperienced. No harm double checking
 
Steve-Scotland said:
Hi,

Thanks - I'm now looking around the gas-safe register to get an engineer out that is authorised to work on unvented cylinders - unless there are any plumbers on here that are ticketed and are able to attend in Central Scotland? Also, any idea what the cost would be(I know thats a pretty dumb question as it would depend on whats wrong and how to fix, but was looking for ballpark on callout charge etc)

Thanks

Steve
Click to expand...
What level of British Gas Homecare do you have? No need to call other companies just yet.
 
Hi everyone,

I've just checked with BG and they have confirmed the engineer that called is ticketed to work on unvented cylinders so am happy with that aspect.

What is still a concern though is that the unknown valve will be replaced with a piece of pipe as I'm sure it must have been put in for a reason.

Has anyone ever seen this sort of set-up before? (if it helps, the valve turns round a scale from 1-6)

Oh, and its Homecare 400 we have

Thanks

Steve
 
Wetbandit said:
And tbh the guys gotta be really inexperienced if he can't work out what it is!

He shouldn't be qualified.
Click to expand...
Inexperienced doesn’t mean dangerous. Let’s see how you feel once you’re qualified and made your first mistake or come across a boiler where you have no instructions and cannot figure out how to take the case off.
 
The fact that the B.G engineer has not identified the cause of the pressure loss and is also prepared to remove a device because "He didn't know what it was" is quite concerning, just as much that his other couple of Guys didn't know either.

3 thoughts;
Have B.G blocked the use of Google on their Engineer phones?
And do B.G not have any inhouse Engineering Technical support, who actually know about systems they maintain and repair?
Do B.G not have a standing instruction along the lines , if you don't understand what you have found, don't just ignore or remove it, seek help?
 
Steve-Scotland said:
Hi everyone,

I've just checked with BG and they have confirmed the engineer that called is ticketed to work on unvented cylinders so am happy with that aspect.

What is still a concern though is that the unknown valve will be replaced with a piece of pipe as I'm sure it must have been put in for a reason.

Has anyone ever seen this sort of set-up before? (if it helps, the valve turns round a scale from 1-6)

Oh, and its Homecare 400 we have

Thanks

Steve
Click to expand...
Ok. If you have 400 that should cover everything including Plumbing. Personally. As an G3 engineer. I would call BG and request a more experienced full time Engineer. It may have been a contractor that attended.
 
@Harvest Fields

Sorry if I upset you pal.

I'm a hvac electrician so have some experience of figuring out how to get into boilers and cylinders etc and agree with what you say as when I was an apprentice I came across things I was inexperienced in but soon figured out what it was doing there is what it is.

Just saying if he spent a bit of time there looking at it and rang two friends and they didn't know he can't of explained it well so can't have a clue what he looking at,
 
Wetbandit said:
@Harvest Fields

Sorry if I upset you pal.

I'm a hvac electrician so have some experience of figuring out how to get into boilers and cylinders etc and agree with what you say as when I was an apprentice I came across things I was inexperienced in but soon figured out what it was doing there is what it is.

Just saying if he spent a bit of time there looking at it and rang two friends and they didn't know he can't of explained it well so can't have a clue what he looking at,
Click to expand...

No offence intended mate. Threw my teddy out the Pram a little then. What I meant was this is an open forum and no offence to the op we only know there side of the story. It is ok giving advise but if it then leads to the op doing the work themselves (not saying they would) this then becomes dangerous itself.
 
Your right pal I suppose I'm eager to get into the conversation when I should of kept my mouth shut,

People who aren't qualified shouldn't be messing with it and I don't want to give them help identifying parts only for them to attempt it.

My bad just getting used to the forum etiquette.

Wet bandit
 
Wetbandit said:
Your right pal I suppose I'm eager to get into the conversation when I should of kept my mouth shut,

People who aren't qualified shouldn't be messing with it and I don't want to give them help identifying parts only for them to attempt it.

My bad just getting used to the forum etiquette.

Wet bandit
Click to expand...
No worries mate. I’m just a stickler for the rules. Especially on G3. As you can see from the Ops post, it is sometimes bad enough when you have supposedly qualified people working on it.
 
Hi there,

Don't worry, I have absolutely no intention of trying to fix anything related to to Central Heating or Hot Water, I was really just trying to get confidence that the valve could be removed safely and replaced by pipe without me being woken one night by a boom or a cascade of water running down my hall.

I've just checked with one of my neighbours that has the same house style and set-up as me, and it appears that he does not have this valve on the hot water draw-off so am now a bit more confident that if he can live without it, then so can we (unless someone wants to say otherwise).

Once again, I really appreciate everyone's input on this - Thank you all

Cheers
Steve

PS. I'm now 99% sure it's a Boss Pressure Reducing Valve
BOSS-PRESSURE-REDUCING-VALVE.png
 
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?
20181024_161657.jpg
 
Three pressure reducing valves!? I cannot for the life of me work out why so many.

First, so long as the control block & tprv is fine 8 cannot tbink of a single positive reason for more unless local pressure is so high it warrants one one the incoming main to ensure absolute max performance...

The prv on the output actually looks new which sets me thinking that there may have been previous issues yet to be clarified....
 
The unknown one on the output has always been there as far as we can remember (I'm not aware of any previous issues that may have warranted the fitting of it, and we bought the house new).

The only way I can work out why its there is possibly to regulate the pressure between the infill to the tank and the outflow to the taps/showers -

Now again, I have absolutely no background in heating/hot water so could be completely off here - but by my reckoning, if the outflow pressure is greater than the infill, then could this be the reason why the hot water pressure at the taps is low (i.e. turn on tap, works well for 20 seconds but then tails off, and then after closing the tap for a couple of minutes, this allows more water to flow in to the tank, building the pressure back up so that again when the hot tap is turned on, the pressure is okay for 20 seconds). So by replacing the large known PRV (if this is faulty and reducing the pressure in), this would hopefully resolve our low water pressure issue).

Finally, if the unknown valve (PRV on the outflow) is replaced by a piece of pipe, would the pressure be equal (i.e. 3 bar in = 3 bar out), or is it possible we could still have an imbalance (i.e. more out than in) and still have the same issue with low water pressure? The reason I ask, is I don't know whether it would be better to insist for him to replace like for like instead of removing and replacing with pipe.

Thanks again
 
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YorkshireDave said:
Three pressure reducing valves!? I cannot for the life of me work out why so many.

First, so long as the control block & tprv is fine 8 cannot tbink of a single positive reason for more unless local pressure is so high it warrants one one the incoming main to ensure absolute max performance...

The prv on the output actually looks new which sets me thinking that there may have been previous issues yet to be clarified..
Click to expand...

Hello YorkshireDave / Steve-Scotland [the OP],

As You intimated Dave no Plumber is going to put a Pressure Reducing Valve [Honeywell DO5] on the Hot Water outlet unless there have been previous problems caused by the water pressure on the Hot Water supply pipework - especially as You have also mentioned there are 2 other Pressure Reducing Valves on the Mains pipework.

However - before just `removing it` a Plumber should investigate why it was fitted in the first place.

IF it is just removed there may be an immediate problem with the Hot Water pressure.

To Steve-Scotland [the OP]:

This is where I have to advise that a Plumber is employed because they will be able to look at the Plumbing / Pipework etc. in your Home and will have a better understanding of the RISKS associated with what I am suggesting:

I would suggest `experimenting` by very gradually increasing the pressure on the Pressure Reducing Valve - that is going to be better than just removing it and `hoping for the best` !

I would advise that when the original problem is fixed by BG some investigation is done by gradually increasing the pressure on the Honeywell Pressure Reducing valve to see if anything happens regarding too much pressure at the Taps / Shower etc.

Before doing that `Test` I advise that the Washing Machine / Dish Washer water supply valves are closed and the hoses disconnected from the valves as a precaution to eliminate any chance of the hoses bursting or damage to the Appliances - because I would not rely on standard quality Washing Machine valves to hold back possibly very high pressure while the `Testing` is going on.

`Better be Safe than Sorry`.

Something else that occurs to me while writing this is that IF the incoming Mains water pressure is so High that it requires 2 x Pressure Reducing Valves BEFORE the Unvented Cylinder / Megaflow and another after it is there a possibility that the Unvented Cylinder is still being fed with Mains water that is under too much pressure for the Cylinder specification ?

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
 
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CHRISX said:
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
Click to expand...

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
 
YorkshireDave said:
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
Click to expand...


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.
 
Last edited by a moderator:
YorkshireDave said:
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.
Click to expand...
I think this conversation has been going on long enough in an open forum boys and girls if there is any on here.
 
Steve-Scotland said:
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
Click to expand...
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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