Mega flow about to explode??

[Rystar00]

Hi guys,

You were so incredibly helpful with a boiler issue I had last year that I thought I'd ask come back and see if I could benefit again from your kind and generous advice.

The issue I have at the moment is as follows:

• I have a megaflo in my basement which is below ground level.
• I don't have an expansion vessel (when I was worried about this the engineer said there is an internal expansion bubble but I'm not sure I believe him!)
• I have a pump connected to the PRV valve which pumps water out to ground level.

Originally the pump would come on a couple of times a day. However it is now going off about once an hour.

There is a steady drip of water from the megaflo to the pump tank. The pump tank has a 5 litre capacity and presumably there is a switch that triggers the pumping when it reaches a certain level.

Should I be worried that the pump seems to be going off more frequently? I attach pictures for reference.

 

[Riley]

If it is a mega flow then they will have an internal bubble. Re the constantly flowing PRV you need a G3 qualified engineer in to look at it to do otherwise and diy is illegal. The PRV pump should only ever go off if there's a problem not any other rime

 

[Last Plumber]

It will have internal expansion

It doesn't sound like you're on the verge of disaster but you do need a G3 engineer to check things over for you

 

[Last Plumber]

It will have internal expansion

It doesn't sound like you're on the verge of disaster but you do need a G3 engineer to check things over for you

 

[Rystar00]

Thanks very much lads. Really appreciate your time.

In your experience what might cause it to discharge once an hour now when it was a couple of times a day before please?

 

[Riley]

Not gonna get an answer mate whilst you might not diy it the next person searching might. We're only concerned for your safety here

 

[Sharp Point]

you need a G3 engineer to sort things, it may need recharging as it seems to be a bubble top or
Have a underlying fault and one of the safety devices is faulty. I personally wouldn't use until it's been checked over.

 

[tamz]

You can recharge the air bubble yourself. It's an owner do able procedure.
Turn off the supply to the cylinder
Open the hot taps until the water stops
Close the taps and turn the supply back on.

It is something that should be done on a regular basis for cylinders with internal air bubbles.
One of the reasons I don't fit them. They are a pita.

 

[Old Account]

You can recharge the air bubble yourself. It's an owner do able procedure.
Turn off the supply to the cylinder
Open the hot taps until the water stops
Close the taps and turn the supply back on.

It is something that should be done on a regular basis for cylinders with internal air bubbles.
One of the reasons I don't fit them. They are a pita.

I'd thought it would not bother you to install an unvented system but it looks totally different what other reason do you have not to install them ?

I hope you don't mind me asking, Tamz,

Kind regards,

Ronny

 

[tamz]

Cylinders with the internal bubble ( like megaflows and the excelsior's shown above) are a pita as they loose the air bubble 2 or 3 times a year leading to it discharging through the tpr.
No matter how many times you show the customers how to do it they don't/won't so its your fault cos you fitted it.
Not so much of a problem if its just around the corner as it is a 5 minute job but not so good when it is 20 miles away.
External vessels take up more space but are a better more reliable set up.

 

[Old Account]

Cylinders with the internal bubble ( like megaflows and the excelsior's shown above) are a pita as they loose the air bubble 2 or 3 times a year leading to it discharging through the tpr.
No matter how many times you show the customers how to do it they don't/won't so its your fault cos you fitted it.
Not so much of a problem if its just around the corner as it is a 5 minute job but not so good when it is 20 miles away.
External vessels take up more space but are a better more reliable set up.

But if you have to recharge it 2/3 times a year then I would not do it for free... if you tell them and show them how to do it then your job is done. You did not cause a leak neither an issue to the system so why doing it for free.
I mean 20miles wouldn't make a sense even though you getting paid it definitely won't pay off.

 

[Old Account]

Cylinders with the internal bubble ( like megaflows and the excelsior's shown above) are a pita as they loose the air bubble 2 or 3 times a year leading to it discharging through the tpr.
No matter how many times you show the customers how to do it they don't/won't so its your fault cos you fitted it.
Not so much of a problem if its just around the corner as it is a 5 minute job but not so good when it is 20 miles away.
External vessels take up more space but are a better more reliable set up.

But if you have to recharge it 2/3 times a year then I would not do it for free... if you tell them and show them how to do it then your job is done. You did not cause a leak neither an issue to the system so why doing it for free.
I mean 20miles wouldn't make a sense even though you getting paid it definitely won't pay off.

 

[Best]

You also lose part of storage area capacity of the cylinder on a Megaflow due to the air gap.
I look at it this way, - Unvented units all need serviced once a year anyway, so the external expansion vessel type are no bother at all for to be maintained. Admittedly the EV needs to be replaced after a few years. Danger with external potable vessels is they are normally actually made of mild steel (same as heating type) but have a balloon membrane so that potable water doesn't rot vessel. Problem with that is when balloon perishes, the steel vessel will rot unknown to you and when they pin hole you get 3bar mains pressure flooding everywhere.
They really should all be stainless steel, but it's the manufacturers keeping costs down.

 

[heliotrope]

You can recharge the air bubble yourself. It's an owner do able procedure.
Turn off the supply to the cylinder
Open the hot taps until the water stops
Close the taps and turn the supply back on.

It is something that should be done on a regular basis for cylinders with internal air bubbles.
One of the reasons I don't fit them. They are a pita.

Did you miss anything out on that procedure to recharge the internal air bubble?

 

[chris watkins]

http://www.fabdec.com/sites/default/files/fabdec/library/3S_Technology_Medium.mov
What are you saying Tamz "that this manufacturers claims don't turn out to be true" well I never that's a first!!! :angelsad2:

 

[Best]

Did you miss anything out on that procedure to recharge the internal air bubble?

Think he forgot to say, - drain cylinder from its draincock and open T&P valve until air fills into that level.
One point is be careful opening any taps at lower floors to any unvented cylinder after mains is turned off, as this could cause the cylinder to implode. Opening the hot draw off fitting will prevent this

 

[tamz]

Did you miss anything out on that procedure to recharge the internal air bubble?

Open the tpr.

It will all be in the users instructions

 

[chris watkins]

OP the system you have looks like a professional installation carried out by someone who holds the Part G ticket.
The use of the correct pump for unvented in a basement tells us that (& the crimp fittings) but shame the system was not handed over to you with all the correct info (O&M's) or did you not have it installed ?

http://www.fabdec.com/sites/default/files/fabdec/library/excelsior.pdf

You do just need to confirm that it is a WD1 unit you have installed with the internal air bubble if it is not holding onto it's charge & the expansion relief keeps discharging then it is a simple job for an engineer to add an external vessel to stop this.

 

[chris watkins]

Can't find any users instructions on line.

 

[joni os]

http://www.fabdec.com/sites/default/files/fabdec/library/ExcelsiorManual.pdf
Should cover it.Page 23

 

[heliotrope]

It is not necessary to drain cylinder to recharge.

opening the lowest tap is all that is required.

Opening lowest tap will not cause implosion.

No water in, no water out. Only opening drain cock
could cause a problem.

 

[heliotrope]

It is not necessary to drain cylinder to recharge.

opening the lowest tap is all that is required.

Opening lowest tap will not cause implosion.

No water in, no water out. Only opening drain cock
could cause a problem.

 

[Best]

It is not necessary to drain cylinder to recharge.

opening the lowest tap is all that is required.

Opening lowest tap will not cause implosion.

No water in, no water out. Only opening drain cock
could cause a problem.

Surely opening a draincock from low area part of unvented cylinder, or opening a hot tap coming from supply pipe from top of unvented cylinder are basically same thing, - same suction applied to the unit?
I think they can implode, - just same as if a copper cylinder had its vent pipe plugged and the valve on its cold feed turned off and a tap opened. I have seen that happening and also when vent & feed pipes frozen in loft.
When on a much lower floor, after isolating unvented cylinder you turn a hot tap on, the high mains pressure will obviously drop quickly, but the suction will be strong. With a high head, it will be very strong. The thin stainless steel cylinders have no strength against implosion.
I just have found a few posts from last few years where unvented units have imploded after water was shut off.
I don't know how true this statement in one of the posts is, but it stated Glenhill were now supplying anti vac valves

 

[tamz]

In theory yes it could happen. In reality it never will.
The only imploded cylinder I've ever witnessed was caused by me (photos on here somewhere)
Syphoning a doublo tank threw the hose out a 5 stories window hose tight in the top connection.
Cylinders are designed to be drained. I've yet to see one that says split a nut when draining.
It's pish

 

[Chalked]

In theory yes it could happen. In reality it never will.
The only imploded cylinder I've ever witnessed was caused by me (photos on here somewhere)
Syphoning a doublo tank threw the hose out a 5 stories window hose tight in the top connection.
Cylinders are designed to be drained. I've yet to see one that says split a nut when draining.
It's pish

Ive seen a copper cylinder implode

 

[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