Expansion Vessel Issue

[benney50]

Hi. 

I have a MAIN unvented cylinder (120 litres) with a separate expansion vessel. I tried to test the expansion vessel by putting a car tyre pressure gauge on the valve at the top. I had no reading so pressed down on the valve with a screwdriver to see if any air (or water) would escape. There was neither present. I was then going to remove the expansion vessel and try to recharge it but upon further reading it seemed that if you have an unvented cylinder you should leave this to a professional due to safety issues. I do have a brand new vessel I could just swap out but again I am unsure to proceed myself. 

I would be very grateful for some advice.

Thanks in advance

Patrick

 

[Sharpend]

What makes you think the original is faulty? 

 

[ProDave]

You don't have to remove it to pump it up. but you do have to depressurise the water.  Turn off your main stopcock and open the hot taps to let any pressure off, then check your pressure and pump it up.

If water comes out of the valve, the bladder is ruptured.

 

[benney50]

Hi. Thanks for that. The reason I thought something may be wrong is when the heating/hot water comes on (by timer) our bath tap and shower starts dripping so figured it may be a pressure issue.

 

[Sharpend]

That sounds as though pressure is too high. I have had to fit a Pressure reducing Valve to our incoming water supply as were going through taps etc at a rate of knots. 

 

[ProDave]

You need the whole thing properly checked over for you own safety.

There are a number of safety features like the expansion vessel, a pressure reducing valve on the input water, an over temperature and an over pressure relief valve that both drain to a drain pipe to prevent the whole lot over pressurising in the event of a fault.

It sounds to me like you might have more than one fault and your system might presently be dangerous.

for gods sake get a qualified plumber used to installing and servicing unvented water tanks to come and check ALL of the safety features.  This SHOULD be done annually anyway even if you are not noticing a fault.

 

[benney50]

Thanks. I have already left messages with some qualified plumbers to try and book a visit but just wanted to check in case it was something simple. We have the system and boiler serviced annually. This is something recent.

 

[benney50]

Hi.

Apologies for late reply. You will be glad to know I got a qualified plumber in who changed the expansion vessel (it was pretty full of water). This seems to have done the trick. He checked out the other elements of my system which were all good. Thanks again for all your help/advice.

Regards Patrick