Please help - now desperate - noisy megaflo system

[sammypow]

Hi

We have just had a new megaflo system installed, approx 6 weeks ago. We are at a loss as to what to do. There is a noise when the taps/shower/bath/kitchen tap is turned on first thing in the morning or first thing in the afternoon once the water has been done. This noise is very loud and is a low drone grrrrrr sound and then kinda of whizzes of high pitch sound. It comes from the loft where the megaflow system is. It is so loud the neighour at the end of terrace can hear it.

The plumber who fitted the system has been back several times and he is now at a loss as to what it is. He has checked the pressure relief valve, has fitted pressure gauges has checked flow rates he has even turned the expansion tank from a vertical position to a horizontal position. He has drained the system down twice.

The most frustrating thing about this noise is that it does not occur every day!! Not sure why it comes and goes!!! It is very sparodic and comes and goes but only when taps are turned on!!

Any suggestions would be greatly appreciated.

 

[josh]

checked the pressure reducing valve? could whistle through that.
Is it when any tap is turned on or just a hot tap?

 

[kozak1968]

Megaflows usually have an internal expansion (bubble top) if the noise is is coming from the unit itself it could be a damaged baffle which holds the air bubble. It will sound worse when no water has been drawn of due to the added pressure build up. Maybe contact Megaflow is best.

 

[chris watkins]

Can you post pictures of the cylinder & control valves / pipework, I know it means a trip into that cold loft but it is the easiest way to see what it is & how it has been piped up.

If it is occurring after the water has been heated it is most likely due to the difference in pressure created between the hot & cold sides.

 

[Dannypipe]

It's not a "Mega Flow" if your plumber has changed the orientation of the expansion vessle as you say.

Mega Flows don't have an external expansion vessle but an integral one. They are the market leaders, and because of this a lot of people call unvented cylinders "Mega Flows" in the same way some people say "Hoover" instead of vacume cleaner.

This is important as Mega Flows in my experience have far less noise issues than standard unvented cylinders.

I answered a list of possible things to try with a noisy cylinder the other week. I will try to track down the post I made and copy N paste it here for you.

 

[REDSAW]

chattering valve syndrome

 

[Dannypipe]

Found it:

Things I found it can be.....

1/The PRV is knackered and over pressurising the system.
2/ A mixer (monoblock tap or even a shower cartridge) is supplied by unbalanced feeds, and the cold is back filling the system, and over pressurising it.
3/ The expansion vessel is flat,punctured.
4/ Pipe work is loose, and vibrating.
5/ A valve on the system has a loose jumped and is vibrating. Loo's can often be the culprit.

6/Orientation of vessle can also apparently make a difference (not been a problem I've come across though.

7/As can if EV is connected with a flexi hose (flexi hoses often have a smaller internal diameter than a copper tube but are supplied with some cylinders and not seen as an issue by many). I've had a issue with one cylinder and hard plumbing the connection to the EV solved it.

8/Finally, some vessels have a restriction in the MI connection. The compression to MI union can cause issues (and infact did cause an issue on a cylinder I installed, and the new EV from the manufacturer solved that issue as it was connected straight to a comp fitting. Hard to explain I know.

 

[sammypow]

checked the pressure reducing valve? could whistle through that.
Is it when any tap is turned on or just a hot tap?

Just when the boiler is on and the hot tap is turned on.

 

[Howsie]

What make is it?

 

[Megaflo-Experts]

From your original description, it sounds like the noise occurs after the water has been heated up, and the hot taps having not been used for a period of time.
Does the noise only occur the first time the tap is opened? If you open the same (or any another) hot tap a few minutes later, do you get the noise again?

Also, when you first open the hot tap, is there an initial burst of water at a higher pressure?

My initial thought is some problem with the floating baffle/air gap within the Megaflo.

Was it the cylinder that was drained down twice, or was it the heating system?

 

[Dannypipe]

The OP has said that their installer has changed the orientantion of the expansion vessel. Therefore it is not a Mega Flow cylinder. I did point this out right at the beginning.

 

[Dannypipe]

I'm going to make a guess here. Is it a Stelflow?

 

[tweakyboy]

The OP has said that their installer has changed the orientantion of the expansion vessel. Therefore it is not a Mega Flow cylinder. I did point this out right at the beginning.

It could be a Megaflo solar, which does have a external expansion vessel.

If the plumber is at a loss and has checked the expansion vessel, get him to replace it. I've had a few Range Tribune cylinders come with faulty expansion vessels which seemed to make a vibration when a hot tap was first opened after the cylinder reached temperature.

 

[Dannypipe]

It could be a Megaflo solar, which does have a external expansion vessel.

If the plumber is at a loss and has checked the expansion vessel, get him to replace it. I've had a few Range Tribune cylinders come with faulty expansion vessels which seemed to make a vibration when a hot tap was first opened after the cylinder reached temperature.

I'm pretty certain the OP would have mentioned it if it was a solar cylinder, plus the expansion vessel would be on primary side and would not cause a noise issue when the hot tap is run.

 

[tweakyboy]

The vessel on the Megaflo solars are on the cold inlet to the cylinder same place as any other make of unvented.

 

[Dannypipe]

Really? In that case I stand corrected.

 

[Dannypipe]

Though I do think the OP would have mentioned if this was a solar thermal install.

 

[tweakyboy]

Really? In that case I stand corrected.

Yeah, definitely I installed one in my house and it comes with a external which goes on the cold inlet. I think :cowboy: