Still Pumping over..but new approach

[WillsNana]

On-going saga started here
//www.diynot.com/forums/viewtopic.php?p=1429824#1429824

Since the heat exchanger was checked and the new valves were put in, we have limped along using the heat only or the ch only, until better weather so that we could have the system powerflushed.

Another plumber checked the piping and said it was done correctly and as I said in my previous post it has all been working fine since Nov 2004, with no problem

The other night we needed hot water and I switched on the emersion for a short while. The following day I manually turned up the cylinder stat for the water to heat up and it started pumping over and has done so every time I have switched it on since.

This morning I sat by the cylinder and it was like a lot of water trickled inside the cylinder, as I turned up the stat. Then water started bubbling up the pipe.

It couldn't be air could it as we have a vent fitted inside the airing cupboard? Could the blockage be inside the cylinder coil?

 

[ChrisR]

I haven't looked at the saga, but I'd
a) turn the boiler stat down. Still do it as much? If not, suspect boiler scale causing local boiling
b) Try it with the gas to the boiler OFF but the pump on.
c) Inspect inlet side of pump, carefully for leaks which could let air in but not let water out.
d) then probably what you knew all along - cut out the pipe where the feed meets the circuit, and clean it out.

 

[WillsNana]

I haven't looked at the saga, but I'd
a) turn the boiler stat down. Still do it as much? If not, suspect boiler scale causing local boiling


It is turned down a little more than usual. Would boiler scale be in the heat exchanger, that was checked and no probs


b) Try it with the gas to the boiler OFF but the pump on.

How?


c) Inspect inlet side of pump, carefully for leaks which could let air in but not let water out.

The valves have been replaced either side of the pump (which is new) and checked by plumber who was rechecking the system.


d) then probably what you knew all along - cut out the pipe where the feed meets the circuit, and clean it out.

From the f/e tank This was replaced by plastic piping, when system was replaced in 2005 (new boiler and rads and flushed through about 3 times with Fernox treatments.

Definitely not the coil through the cylinder then?


Thank you for replying to my post.