MegaFlo again. Pressure loss

[pharmer9]

Hi there -
I am convinced that my 25 yr old Megaflo is providing less hot water pressure than it used to. I have reset the bubble several times but it doesn't seem to help. But the shower pressure is not bad and I can live with it.
But then yesterday I got up earlier than usual (before the HW and CW timer kicked in to light gas boiler) and the HW had zero pressure - no flow - not even a trickle (while CW was still giving good pressure).
Half an hour later, boiler had kicked in and HW flow came back on to its usual level. (Water in Megaflo was still hot/warm from previous evening, so we are not talking massive change freezing cold-to-hot)
All I can think of is some transient physical blockage. Lime scale? I do have a softener but the water is really hard around here.
Is there anything else it could be? Is there some sort of valve in a typical unvented HW circuit that could restricts HW flow in this way? Could a plumber with some sort of pressure gauge troubleshoot this?
This has happened once or twice before, but I didn't believe it. Now I know it is real!
Thanks for any ideas

 

[SimonG]

When was it last serviced?

 

[king of pipes]

Yes there is but you will need a G3 registered engineer to diagnose and repair the problem but consider a 25year old cylinders is not bad going could be time for a upgrade ? Kop

 

[pharmer9]

When was it last serviced?

Errrr..... Good point. They need servicing?

 

[pharmer9]

Yes there is but you will need a G4 registered engineer to diagnose and repair the problem but consider a 25year old cylinders is not bad going could be time for a upgrade ? Kop

I guess I will have to stop thinking of the Megflo as "only" being a metal tank with hot water in it and a few circuits, and accept that it might need professional attention

Thanks for the reality check

 

[Riley]

In reality if not looked after correctly they can be very dangerous. Definitely get a g3 engineer to look

 

[SimonG]

Annual service required.

 

[pharmer9]

Annual service required.

Thank you both for your learned and civil input

 

[clemda1]

More thank likely just the non return valve in the Combi valve getting degrading or getting stuck with scale or build up of crap in the inlet filter. Seen it quite a few times. just get a g3 registered plumber to swap it out for you. Looking at a few hours (dependent on height of the valve relative to drain down) and cost of valve about £100 give or take.. if you ca find an old style version then should be quick swap out if not the new versions may require a little pipe work adjustment to make fit.

 

[chris watkins]

More thank likely just the non return valve in the Combi valve getting degrading or getting stuck with scale or build up of crap in the inlet filter. Seen it quite a few times. just get a g3 registered plumber to swap it out for you. Looking at a few hours (dependent on height of the valve relative to drain down) and cost of valve about £100 give or take.. if you ca find an old style version then should be quick swap out if not the new versions may require a little pipe work adjustment to make fit.

Hi Clemda1, with respect could I suggest that your post provides a bit too much info which might tempt the OP to have a go themselves and as they are not G3 this could be seen as encouragement to break the Law?
We all want to be helpful on here but sometimes it best not to go into too much detail, just for the record I accept I have a vested interest in this but when you see the results of "have a go heroes" you would understand.
Regards Chris

 

[clemda1]

Hi Chris,

I did specifically say “get a g3 engineer to do the repair” but point taken will be more mindful going forward.

 

[chris watkins]

Hi Chris,

I did specifically say “get a g3 engineer to do the repair” but point taken will be more mindful going forward.

Thank you

 

[pharmer9]

Happy ending. Combi- valve replaced (by engineer, not me) and pressure restored.
Thanks all
PL

 

[Welder]

Happy ending. Combi- valve replaced (by engineer, not me) and pressure restored.
Thanks all
PL

Thank you for letting us know.

All too often, the response 'get it serviced' is interpretted by people seeking help as some form of protectionism for plumbers. Unfortunately no builder I have ever experienced explains to their customers that their shiney new unvented cylinder requires an annual service to remain effective and, more importantly, safe. So, when we plumbers tell people of the reality, their immediate response is to shoot the messenger.
You didn't so thank you for your understanding.
Please tell people you know with a similar system that they too need to get it serviced annually.