Leaking Megaflo HW tank

Keldin

I've got a newish (8 months old) high pressure Megaflo hot water tank that leaks occasionally from the prv (i think thats what its called). It only happens when the water is being heated and is pretty much at the maximum temperature. It's not a lot and doesn't contimue after the boiler is off.
I have followed the service instructions on the side of the boiler (turn of incoming cold, open hot tap and open prv) but that doesn't seem to help. I have also tried draining the tank but very little water comes out considering how big the tank is.
After the water has been heated the pressure does seem a little higher than normal as if I open a hot tap there is a short burst of high pressure water and it settles down to mains pressure again.
Does anyone have any ideas or will I have to get the plumbers out?
Thanks
K

alanobrien

PRV is likely to mean Pressure Relief Valve.

Check the manufacturers recommended pressure setting for the unit against actual setting. Could be the unit is over pressurised or the valve is duff.

Skiduck

pressure should be set to 1.2 to 1.5 bar

Keldin

I think it's actuallt the expansion relief valve that drains into the tun-something.
There is nowhere to set the pressure - i think it come son at 3 bar and there is a prv that is set to allow a max of 8 bar into the system.

jock58

It would be best to call in a Plumber with an Unvented ticket(training on unvented cylinders G73?) as they can be very unsafe in the wrong hands.

BobProperty

jock58 wrote:

It would be best to call in a Plumber with an Unvented ticket(training on unvented cylinders G73?) as they can be very unsafe in the wrong hands.

Shouldn't be fiddling with it without one. As it's only 8 months old, get the person who installed it back, or at least get them to explain what the allowable settings / pressures etc. are supposed to be. If that fails, I think Megaflow themselves are usually pretty customer friendly on the phone and willing to explain their products to end users.

Skiduck

Keldin wrote:

I think it's actuallt the expansion relief valve that drains into the tun-something.
There is nowhere to set the pressure - i think it come son at 3 bar and there is a prv that is set to allow a max of 8 bar into the system.

it's the tundish, the word you are looking for (not meaning to sound patronising)

if the PRV is set to 8 bar, there is something wrong. As suggested, get a ticketed unvented engineer out ASAP, I believe your system may be pressurising itself. Hopefully someone else can back me up on this.