On 01/06/11 14:44, Grumps wrote:
wrote in message
...
Hello

We've got a 28 yr old Potterton conventional gas boiler serving a hot
water cylinder and 11 rads.
Over the past couple of weeks our old boiler has started boiling the
water. It has kettled for a few years, but this boiling is a new
development.
The British Gas man (we have maintenance on this old thing) said it was
most likely sludged up either in the HE or pipework around the boiler, and
thus the water is not circulating fast enough so it boils.
I thought we had a Y-plan system but can't seem to figure out the pipes in
the airing cupboard. I have posted a picture he
http://i56.tinypic.com/2vnj638.jpg
Physically the boiler is in the direction of the arrow shown.
"This looks like it comes from the boiler" is a pipe that goes to the coil
of the HW cylinder.
"This doesn't go to the boiler" is a pipe that doesn't appear to be in the
direction of said boiler and connects to the base of the pump.
I was expecting the hot from the boiler to go to the base of the pump!
I know it's difficult looking at just this one picture, but can anyone
explain if it is correct?
Ta.

Oh, and the other thing was that the BG man put a "do not use sticker" on it
due to the fact that hot/warm water is getting into the header tank and
making it, er, warm - which appraently it's not designed to do.
The risk being that the tank deforms and splits and the water comes out
which will be replaced by fresh water from the ball-cock.

If that happens the never-ending supply of cold water coming from the ball
cock will only be a minor comfort to anyone who happened to be under a split
tankful of boiling water pouring through the ceiling onto them...

People have been killed in this circumstance.