Easier solution to fitting external EV

[DarrenSL]

I'm in the process of fitting a new external EV on my Halstead Finest Platinum. I noticed that the existing EV is connected via a braided pipe and figured that the easiest way to do this job would be to simply connect the new EV using a similar pipe. The pipe would need to be about 1m long to reach through the back of the boiler.

Anyone know where I can get hold of such a pipe? (including 90 degree bend) - see attached. I'm not sure what the fitting size is. Looks less than 15mm to me.

Untitled

• DarrenSL
• 9 Jan 2013
• 1

Thanks

 

[dcawkwell]

There is probably nothing wrong with the existing expansion vessel. Just needs the boiler draining and repressurising to 1 bar with a foot pump.

 

[gas112]

Or that pipe could be blocked

 

[DarrenSL]

No definitely gone. Water gushes out when the valve is pressed. I was actually wondering if the rubber seal in the EV was actually necessary given that the EV is the highest point in the system so any air should naturally collect there.

 

[dcawkwell]

Best way is cut into the central heating return pipe and add an external
expansion vessel. A £20 one will do it.

 

[misterdubya]

How much water? Just plumb it into the return.

Edit: dc has summed it up.

 

[DarrenSL]

Well, when i press the valve a flood of water not too dissimilar to an open tap gushes out half way up to the ceiling. Far too much to be condensation.

I'm ok at cutting and soldering but it seems a much simpler job to simply add a braided pipe and do the job in 10 minutes (although I appreciate it costs quite a bit more this way). But if such a product is difficult to get hold of then not a problem I'll just do it the recommended way.

Thanks

 

[matt1e]

I was actually wondering if the rubber seal in the EV was actually necessary given that the EV is the highest point in the system so any air should naturally collect there.

where it will slowly dissolve into the water
you need to keep the two separate mate

 

[TheGasMan26]

That fitting isn't a 15mm/1/2", not sure what they are as I tried what your suggesting on a similar boiler with a long flexi tap connector.

Just buy a compression T piece 22/22/15-and a flexible tap connector(15mm x 3/4"/22mm), cut the compression T into the return, insert a few inch's of 15mm copper & use the tap connector to hook up to the external EV, this is alot faster & easier than messin about soldering.

Another temporary fix is to choose a small radiator that isnt used much, isolate & drain it, then simply open 1 of the valves & top up sytem pressure, ideally on the return to boiler side(the pipe that gets coldest last) and leave the other closed, this then works as an EV indefinitely.

Also some EV's will leak if not pressurised as the membrane slips and fails to provide a seal, the correct procedure to ensure your not swapping a faulty EV is to remove schraeder core using a special tool(cheap to buy)then put a bit of tubing onto it, now fill up system and see if the water eventually stops, this can be several litres, if the water stops replace schrader, drain boiler & leave drain open, try to pressurise EV(if its totally gone it wont hold any pressure), if this pressurises test the schraeder valve with a small amount of soapy water for leaking air, refill system and heat test. This is important to check as quite a few EV's will pass water if not pressurised as the membrane is the seal.

 

[DarrenSL]

Thanks Gasman (and everyone who has commented).

Not too sure about removing the schraeder valve (it's a bit fiddly behind there and I'm sure to drop it!) so I'll probably use an old bike pump and cut off the valve end.