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.