Mega flow about to explode??

[Best]

I had to completely drain an unvented cylinder a few months ago to replace a leaking combination valve. (Idiot installer had fitted the valve low down and at rear of unit, so had to drain cylinder)
It was a 2 floor house, with cylinder on the upper floor. To drain it all I had to do was open the bath cold tap on lower floor because the balanced cold on this unit is teed after the combination valve.
I diconnected the hot pipe outlet at top of cylinder to prevent implosion and there wasn't a sound as it drained, but I showed customer the suction by putting my hand over the connection and letting go. It's like a powerful vacumn cleaner.
I am not taking risks with what is basically a bean tin. :smile:

 

[Old Account]

I had to completely drain an unvented cylinder a few months ago to replace a leaking combination valve. (Idiot installer had fitted the valve low down and at rear of unit, so had to drain cylinder)
It was a 2 floor house, with cylinder on the upper floor. To drain it all I had to do was open the bath cold tap on lower floor because the balanced cold on this unit is teed after the combination valve.
I diconnected the hot pipe outlet at top of cylinder to prevent implosion and there wasn't a sound as it drained, but I showed customer the suction by putting my hand over the connection and letting go. It's like a powerful vacumn cleaner.
I am not taking risks with what is basically a bean tin. :smile:

It's safer and cheaper than replacing a cylinder out of your own pocket

 

[Old Account]

I'd thought there are some valve you could install to recharge the cylinders without draining down. They have got the Venturi effect ... when water is filling the cylinder it suvks air in and it will automatically recharge. I believe I've seen those ones before

 

[tamz]

I'd thought there are some valve you could install to recharge the cylinders without draining down. They have got the Venturi effect ... when water is filling the cylinder it suvks air in and it will automatically recharge. I believe I've seen those ones before

Chris's post #15

 

[zzzjim]

.....what is basically a bean tin......:smile:

I'm sure baked bean tins would be even thinner if made of stainless !

( Sadly we live in a world designed by accountants and computers ... )
( with China in the race to the bottom for cost and reliablity ... )

Hence the expertise of 3G required to handle a modernised cyclinder - made of less metal

 

[Rystar00]

Thank you very much gents. I really appreciate your time and sorry for the delay in replying!

Yes it was installed by a professional, who confirmed that there was an internal bubble.

I'm fairly handy with DIY but don't want to mess around with the cylinder if it might cause it to explode. Is this something I could do myself having read up on it or would it be best to leave it to a pro?

In the long term would it be worth me asking the plumber to show me how to recharge the bubble or would it be better to get an expansion vessel installed? What would the price be for the latter roughly do you reckon (I'm in the South East)

 

[Rystar00]

Thank you very much gents. I really appreciate your time and sorry for the delay in replying!

Yes it was installed by a professional, who confirmed that there was an internal bubble.

I'm fairly handy with DIY but don't want to mess around with the cylinder if it might cause it to explode. Is this something I could do myself having read up on it or would it be best to leave it to a pro?

In the long term would it be worth me asking the plumber to show me how to recharge the bubble or would it be better to get an expansion vessel installed? What would the price be for the latter roughly do you reckon (I'm in the South East)

 

[Rystar00]

I've found the instructions (see picture) and it sounds easy enough.

How would I "operate" the PRV please? I've taken a picture of that too.

Thanks again guys!

 

[Best]

The valve that is directly into the cylinder on your photo just needs held open by normally turning the plastic knob anti-clockwise a little and holding it open for a short time to allow air to fill the air gap.

 

[ShaunCorbs]

but be warned it may not seal again so you will require a g3 engy to replace the valve

 

[joni os]

If valve doesn't seal when closed:-
With cold feed/combination valve open, turn off all hot water outlets and open valve again to briefly flush seating by discharge through tundish. May take 3 or 4 attempts before valve seats properly. Air pocket will be unaffected because cold water entering replaces discharge through PRV. If this fails,as above, G3 and new PRV.

 

[joni os]

If valve doesn't seal when closed:-
With cold feed/combination valve open, turn off all hot water outlets and open valve again to briefly flush seating by discharge through tundish. May take 3 or 4 attempts before valve seats properly. Air pocket will be unaffected because cold water entering replaces discharge through PRV. If this fails,as above, G3 and new PRV.

 

[Rystar00]

Hi guys,

Just thought I'd follow up.

I think it is the internal bubble and I need to recharge it.

I watched a few videos on YouTube and it seemed easy enough but unfortunately I think they related to Megaflo systems. I think on mine I actually need to get a pump and pump up the Schrader (see instructions attached).

I know how to drain the tank and open the PRV but would one of you kind gentlemen point out where the schrader valve is please and explain how I would open the "shut off valve"? I have attached pics to refer to.

Thanks again guys!

Ryan

 

[Rystar00]

Hi guys,

Just thought I'd follow up.

I think it is the internal bubble and I need to recharge it.

I watched a few videos on YouTube and it seemed easy enough but unfortunately I think they related to Megaflo systems. I think on mine I actually need to get a pump and pump up the Schrader (see instructions attached).

I know how to drain the tank and open the PRV but would one of you kind gentlemen point out where the schrader valve is please and explain how I would open the "shut off valve"? I have attached pics to refer to.

Thanks again guys!

Ryan

View attachment 29084View attachment 29085

 

[Best]

Ryan, it seems now you DON'T have a Megaflow, or any other internal bubble unvented unit!
You must have an external expansion unit, which is entirely a different story. You cannot work on those unvented units, in any way, unlike the Megaflows air gap replenish.
Forget about doing anything yourself. Certain tests and pressures need carried out, which is a normal part of a yearly service. Get whoever installed the unit or any G3 qualified person to service the unit as it is the law. Keeps the unit safe and the paperwork done for warranty of normally 25years.

 

[tamz]

There are 2 different types of your system If you don't know the difference or know what a big blue orwhirte expansion vessel looks like spend 50 or 60 quid phoning some one wh does.
I was going to say phone a friend but unfortunately if you live in city you are unlikely to know the guy next door never mind your local tradesman. Such is the modern world and don't trust checka trusted whatever cos they are shyte and only collect cash from desperates

 

[chris watkins]

While your Part G engineer is on site & the system is drained they will also remove & relocate the isolation valve that should not be there.

It really isn't worth playing around with these potentially dangerous systems if you don't know what you are doing, Ryan

At least for the first time, once you have seen it done & the system is corrected, it might fall under a user operation.

As per Tamz above, do your research & ask to see their Part G / unvented certificate.

 

[joni os]

The instructions on cylinder and external setup of pressure reducing valve and pressure relief valve do not appear compatible from your photo. This alone should warrant the attendance of a G3 qualified technician.

 

[Rystar00]

Thanks again for your input guys.

Just checking you have seen the instructions which I put in one of my pictures? The instructions talk about an internal air gap and no expansion vessel.

The person who installed it (G3 qualified) told me it had an internal air gap but he's very difficult to get hold of and is probably interested in more profitable work rather than coming back to help!

On the basis of the instructions it seems easy enough to do myself, I just needed a few pointers on how to locate the Schrader valve.

 

[Riley]

You're missing the point you're not qualified to work on it

 

[Best]

If you find a schrader valve that means you need to find a G3 plumber.
It's all about money, isn't it?

 

[Rystar00]

Yes and no.

What is the point of spending something money that can beeasily, and safely, done by the user?


I was advised earlier in the thread that this issomething (albeit on megaflo systems) that could be done by the user which iswhy I asked a legitimate question.

If the advice now is that I need a G3 qualified plumberthen I will of course pay for that. However finding someone who is reliable and willing to come out for asmall job like this is a different matter.

Maybe in NI you have a stream of reliable plumbers thatcharge reasonable prices! Where I amI've had 4 ... the first one ripped me off after I'd paid a £2k deposit, thenext 2 lied about being G3 qualified and the last one underpriced so has been anightmare to pin down. forgive me fortrying to avoid the b*llache of dealing with a bunch of jokers.

 

[Best]

Fair enough. If it has an air bubble then you should replenish the air yourself. Not a hard job for anyone and perfectly safe and legal. But if it has external expansion, you must get a G3 plumber. You need to be certain what exact unit you have. I couldn't work on unvented when my G3 lapsed for a while
I have no doubt there are plenty of cowboys everywhere. You could try posting on the Looking for a Plumber part of forum asking for a local G3 plumber to sort it for you. In my area I would think it would only cost a callout charge for a complete service