I had a Heatrae Sadia Megaflow 170 S type installed about 3 years ago in my bungalow (the boiler is oil fired). Recently since building a 1 story extension with upstairs basin and shower added to the system, the temperature/pressure relief valve opens when the water reaches its set temp of 55 degrees, (pressure is at 1 bar). I have followed the instructions on the side of tank loads of times to regenerate the internal air gap with no luck. Heatrae Sadia arn't very helpful, can anybody shed any light.
Heatrae Sadia Megaflow relief valve
- Thread starter jagspit
- Start date
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You should have at least 3 bar cold inlet pressure for a megaflo to work to its full advantage.
The temp/pressure relief valve is usually set to open at 90C, not 55
You could have a faulty safety valve or a problem with the megaflo bubble. They have a bad reputation for the bubble going.
Staff at Heatrea haven't been helpful or motivated since Baxi took them over, in fact lots have left because of it. Another case of Baxi mucking up an otherwise good manufacturer.
As they are only about a mile down the road from me I know a few of them tht haveleft.
The temp/pressure relief valve is usually set to open at 90C, not 55
You could have a faulty safety valve or a problem with the megaflo bubble. They have a bad reputation for the bubble going.
Staff at Heatrea haven't been helpful or motivated since Baxi took them over, in fact lots have left because of it. Another case of Baxi mucking up an otherwise good manufacturer.
As they are only about a mile down the road from me I know a few of them tht haveleft.
gas4you-thanks for the reply, the 1 bar I quoted is set on the guage on the pressure vessel, I presume this is only for the central heating. The cold inlet pressure itself is very strong. Could you please explain more about "the bubble" and how to restore it.
You have tried the bubble restoration already and it hasn't worked. You'll need a G3 qualiflied plumber to come out and fit a new valve and check that the cold combi valve is working OK.
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Have you really followed the instructions?
I'm not being a snideygit but a lot of folk fail to realise they have to stand there like a teapot holding the p&t valve on the side of the cylinder open, maybe for 15 minutes, while the water glugs painfully slowly out of the lowest hot tap.
If you're in a bungalow you'll have very little "head" for it to do that. You would in that case do better to drain from the cylinder drain cock, at the bottom somewhere.
ie turn off mains iso valve, connect hose, open drain, then hold p&t valve open for 15 minutes ...
I'm not being a snideygit but a lot of folk fail to realise they have to stand there like a teapot holding the p&t valve on the side of the cylinder open, maybe for 15 minutes, while the water glugs painfully slowly out of the lowest hot tap.
If you're in a bungalow you'll have very little "head" for it to do that. You would in that case do better to drain from the cylinder drain cock, at the bottom somewhere.
ie turn off mains iso valve, connect hose, open drain, then hold p&t valve open for 15 minutes ...
Been there many times with the customer moaning about being charged by the hour.
Well you could have always read the s0dding manual!.
Thanks folks, have read the manual many times, have held the p&t valve open for 2 hours with the aid of a lightly gripped molegrip but no water comes out of the hot tap only the p&t into the tundish, then released the valve when the gurgling stoped. I have found that if I thunp the tank with my fist with the p&t valve open the gurgling will start again.
The bubble is more like the old gasometer principle I beleive, and from what the op has said by banging it it seems to release it, so I am therefore assuming it is sticking for some reason.
As stated before Megaflos are notorious for problems with this, which is why I moved away from fitting them, even before Baxi bought them out
As stated before Megaflos are notorious for problems with this, which is why I moved away from fitting them, even before Baxi bought them out
And thats why I prefer their second line the Santon with a seperate EXV.
I still cannot envisage any problem with the bubble.
Banging might just cause a ripple which does something but it makes me wonder if there is a bit of loose plastic or foam or something inside.
Again a requirement for a G3 qualified engineer to visit.
I got my fingers burnt with the last one I visited !
Tony
I still cannot envisage any problem with the bubble.
Banging might just cause a ripple which does something but it makes me wonder if there is a bit of loose plastic or foam or something inside.
Again a requirement for a G3 qualified engineer to visit.
I got my fingers burnt with the last one I visited !
Tony
Gents
This notorious problem with the Megaflos "bubble", can this be overcome by fitting an additional expansion vessel to an Existing Megaflo ?
This notorious problem with the Megaflos "bubble", can this be overcome by fitting an additional expansion vessel to an Existing Megaflo ?
Did they not have a problem with the baffle destabalising inside the cylinder which in turn broke the integrity of the air bubble - or am I talking Horlicks?
selfbuilder - yes you can. Has to be for Potable water, ie blue or white and not red.
You know if yer bubble's in trubble by the flow from the hot tap when you turn off the input. It should run on for 10 minutes or more. If it stops immediately, something's burst your bubble.
As I said, use the drain cock. Some Megaflo guys use nowt else.
Can't see how a bubble can have a "fault" except a leak - which you'd know about!
The Baffle's supposed to reduce the rate of dissolution of air gases into the water - it isn't needed as such.
You know if yer bubble's in trubble by the flow from the hot tap when you turn off the input. It should run on for 10 minutes or more. If it stops immediately, something's burst your bubble.
As I said, use the drain cock. Some Megaflo guys use nowt else.
Can't see how a bubble can have a "fault" except a leak - which you'd know about!
The Baffle's supposed to reduce the rate of dissolution of air gases into the water - it isn't needed as such.
As mentioned in another post - I think Megalfo had trouble with turbulence detabalising the baffle.
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