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jonty53 · Joined: 02 Apr 2008 Posts: 3 Location: STONE, STAFFS

Our plumber flushed our oil-fired central heating system out in November. Since then and 4 new hot-water cylinders later the overflow on the topper tank is still overflowing. It is not a leaky ballcock. It seems to be being filled by the cold water tank adjacent to it which is continuously dribbling in. There is no link between the two and the plumber says that the only way this can happen is when there is a pinhole in the coil of the hot water cylinder. The central heating which is pumped is working fine. The hot water is gravity fed and the top of the coil is red hot and the bottom cold. What appears to be happening is that water is going from the return up into the topper tank in the loft and causing the overflow. I am going into the loft daily and taking about 8 litres of water out of this tank to stop it overflowing as it is causing dampness at the back of the house. The system is 20 yrs old and nothing has been done or added to change the system. The plumber has been out 6 times to flush and check the system for blockages but to no avail. The hot water cylinders are described as suitable for a gravity fed system. Any ideas would be much appreciated. Sad

thescruff · Moderator Joined: 03 May 2003 Posts: 4164 Location: Bath

Loads of idea's but first can we clear up a few technical details.

Which tank is overflowing the small header tank for the heating or the larger Storage tank for the hot water cylinder.

What is the make and model of the boiler.

Did the problem start, prior to and lead to the power flush.

I agree with the plumber, up to the point when you say 4 cylinders, then it turns to no chance, unless he is damaging them on installation.

jonty53 · Joined: 02 Apr 2008 Posts: 3 Location: STONE, STAFFS

It is the smaller central heating topper tank that is overflowing. The boiler is a 15yr old Trianco EuroStar oil boiler. He didn't power wash the system out but flushed using mains pressure. Other folks in the road have power washed and had all sorts of problems after. The water comes out squeaky clean. The problem started after he did this.
He has put in a loop in the loft connecting the overflow from the feed to the supply from the topper tank which drops down the return to the boiler. When we open this it forms a loop and the hot water circulates up and back down the return to the boiler. The bottom of the coil is lukewarm. If I turn it off the bottom of the coil is stone cold and the return to the boiler also goes cold.
Thank you for your help.

thescruff · Moderator Joined: 03 May 2003 Posts: 4164 Location: Bath

What the ferk is he.

Don't let him touch anything.

Photo please

jonty53 · Joined: 02 Apr 2008 Posts: 3 Location: STONE, STAFFS

poolcorgi · Posted: Thu Apr 03, 2008 7:20 pm Post subject: