Heatrae Sadia Megaflo problem

[magicman]

Hi guys.

Had a dripping through the discharge pipe, visible through the tundish for ages.

Tried recharging the air gap to no avail.

Had the 3 bar sustaining valve and 8 bar PRV valves replaced and it still done it.

Forgot about it for a while, but now its actually running through the tundish. Recharged the air gap yet again today and again - No joy!

The water running through the tundish is cold.

What am I missing?

Cheers

 

[magicman]

**Reducing valve**

 

[Rybo_1]

Is it sealed heating and possibly had the relief teed into the same D1?

 

[Best]

Need to be G3 qualified to do any work on an unvented unit (except recharge a Megaflo air gap). So the person who replaced the t&p & pressure relief valves should be qualified & have easily been able to find out what valve was passing & what was causing it.
If water is def coming from the unit itself, then it is either getting up to too high a pressure of water from some source, or same is happening, but because air gap is not holding.

 

[magicman]

Rang Heatrae this morning who ensured me it definately sounds like the air gap.

The only difference they told me to try (due to mixer taps in the prop) is to turn the water off the prop entirely, rather than just turn it off at cyl - Which is what I have been doing.

Needless to say... That didnt work either!! Still streeeeeaming through the tundish!!

note - water is cold through tundish....

 

[buckley plumb]

actually seen one do this and it was an unbalanced mixer tap passing .

 

[magicman]

Thats handy. Every tap in this house is a ruddy mixer!! Haha

So go around isolating each mixer one at a time until it stops?

 

[buckley plumb]

no they can pass when off

 

[magicman]

Isolate water to cyl. Open up lowest hot tap until stops.

Then open up hot taps one by one - If water come out = problem tap?

 

[dancinplumba]

Be careful with what you are doing, best to get G3 plumber in, what you have put above could cause damage to cylinder IMO

 

[magicman]

There must be a way I can identify if a mixer tap is the problem?

 

[Best]

There is an easy way to test if the water is coming from a higher pressure outlet, by doing a test at unvented unit. But it needs to be all looked at & tested by a G3 plumber.
You could just test each mixer tap or shower by isolating each supply, but you could destroy the unvented cylinder if outlets are below it.

 

[magicman]

no they can pass when off

I cant see how they can pass if there is the facility to isolate them? I dont mean leaving them turned off functionally

 

[magicman]

Spoken to a G3 - Who has said it could be the baffles and cyl needs replacing as thy are not a serviceable part.

Got a G3 coming round tomorrow. Will post what he finds if anyone is interested?

 

[Best]

Spoken to a G3 - Who has said it could be the baffles and cyl needs replacing as thy are not a serviceable part.

Got a G3 coming round tomorrow. Will post what he finds if anyone is interested?

Yes, please do! Would be good to know how it works out for you.
If the Megaflow needs replaced you can get very much cheaper unvented units, some can be got with air bubble design like Dimplex & lots of others are expansion vessel types.

 

[buckley plumb]

if the baffle has gone fit an external vessel cheaper than new cylinder

 

[Best]

MegaFlow probably won't honour warranty if you add a expansion vessel, but that's a good idea.

 

[magicman]

For anyone interested.... I still have this problem!!

Still havent been able to sort this!

First bloke never turned up 4 days on the trot, so told him to do one.

Next bloke has been busy, but has popped in a few times to try and sort. He said the mixer in the kitchen is not the problem (We just had a new sink fitted)

He fitted a 3 bar reducing valve to the incoming underneath the kitchen sink... Still not sorted.

Think he's coming back next week...

I'm having to turn the water off to the cyl every time I go out, or to sleep etc. This is really doing my head in.

 

[magicman]

MegaFlow probably won't honour warranty if you add a expansion vessel, but that's a good idea.

Heatrae won't touch it, as it was fitted over 10 years ago anyway.

Plus, there is already an expansion vessel fitted

 

[Neil K]

How many mixer taps in the property?

 

[magicman]

6 mixers

 

[Neil K]

Stick non return valves on the 6 hots.

 

[Best]

If you now have a 3bar pressure reducing valve on incoming mains (assuming it is working) and water is still discharging at Megaflow, then unless you have another branch of the mains somewhere else that is not pressure regulated & going to a mixer, you must have something wrong at Megaflow.
Are you sure that you don't have a sealed heating system with its discharge pipe linked into Megaflows discharge? Filling loop passing water?

 

[Neil K]

Or mains mixing with the hot at one of your six mixers. You need a G3 plumber fellow

 

[magicman]

Yesterday, I turned the water of to the entire house.

Opened lowest hot, and opened T&P until drained.

What confused me is that, although the discharge through the tundish slowed to a drip, it was still dripping continuously even though the hot is drained and the incoming is off!


PS. G3 is coming round again this week. This forum will possibly help me tell him any suggestions.

 

[Neil K]

Have you had the t & p valve changed?

 

[Best]

Does sound like you have a faulty valve (which I think you got replaced?). Maybe a bit of crud in it?

 

[Best]

Yesterday, I turned the water of to the entire house.

Opened lowest hot, and lopened T&P until drained.

What confused me is that, although the discharge through the tundish slowed to a drip, it was still dripping continuously even though the hot is drained and the incoming is off!


PS. G3 is coming round again this week. This forum will possibly help me tell him any suggestions.

A decent G3 plumber should be able to narrow down to whatever is causing the discharge in a matter of seconds!
Only thing that would cause any problems for a plumber would be if he found it to be a mixer somewhere passing, but couldn't isolate them to test.

 

[magicman]

Have you had the t & p valve changed?

Water through tundish is cold. When I hold open the T&P it comes through hot.

 

[magicman]

A decent G3 plumber should be able to narrow down to whatever is causing the discharge in a matter of seconds!
Only thing that would cause any problems for a plumber would be if he found it to be a mixer somewhere passing, but couldn't isolate them to test.

I think that's the point in which he's at. Shower mixer iso valves behind tiles etc...

 

[magicman]

It was doing it before it got replaced. But since then, the (new) 8bar relief has been taken off and cleaned...