Flowmaster unvented system venting water to outside of house

[Susanminky]

I have noticed that when the emersion heater comes on some water pours out of the expansion pipe. This happens every day. Then all of a sudden the whole tank emptied out of the wall with really hot water. The system was then ok and now it is just filling with water all the time and it is coming out thru another overflow. Any ideas. My plumber has been round for 3 days and still cant suss it out. Is it a fault with the actual cylinder? It is being confused by an aga which operates into the same overflow. HELP

 

[unguided1]

firstly you need to ask your plumber if he has his unvented ticket then ask to see it Because if he is not qualified to work on it he is putting you in danger

 

[Blackcatgas]

The air gap needs remaking/the expansion vessel is shot, it shouldnt share a blow off with your aga. Susan Minky, thats a cool name.

 

[Susanminky]

thanks for your help. Ive now isolated each system and i think i have 2 faults one with the boiler and one with the flowmaster. Is it normal for a flowmaster to expell a bit of water when it come on or not?

 

[GrahamM]

No, it is not normal. I suggest you procure the services of a qualified gas engineer with his unvented qualification to investigate and advise.
Unvented systems can be dangerous if not installed or maintained correctly.

 

[mickie]

i know little of unvented systems but what makes an unvented system dangerous, if its got thermistors, pressure reducing valves, prv's and trv's fitted ?

i should really know this but being gas safe, this still doesnt mean im legaly allowed to work on unvented ?

 

[mickie]

i guess im not ? even though i put one together years ago at college

 

[AWheating]

In basic terms the reason why an unvented cylinder is so dangerous is if fitted incorrectly and a situation happens where the cylinder overheats and then structually fails it will cause an explosion which can take down your property.

Many installers that do not know what they are doing make very simple but bad mistakes like installing isolation valves between the prv and other parts of the installation. A simple stop tap in the wrong place can lead to a major problem which is why you need to know what your doing, atleast they now make the cylinder manufactures install a temp pressure relief valve themselves to ensure atleast something is right.

It is not hard to install an unvented system correctly, but its alot easier to install one incorrectly and cause harm to persons or property.

 

[pobsdad]

Went to service an unvented unit yesterday and someone had fitted the wrong stat (no oh cutout) in the immersion,AND an isolation valve between the cylinder and the expansion vessel!Clever,eh?

 

[tackleburger]

Connected to an AGA eh? Mmm either as stated your expansion vessel is gone or it's overheating. I wonder, three days to suss the problem, clearly not up to it. Did he fit it? Is the AGA gas or solid fuel?

 

[tackleburger]

Went to service an unvented unit yesterday and someone had fitted the wrong stat (no oh cutout) in the immersion,AND an isolation valve between the cylinder and the expansion vessel!Clever,eh?

I had one on a Johnson & Starley air unit heated with sealed primaries to the unvented. No high limit interupter on the water heater, no two port valve just a pump.