On Wed, 13 Jul 2016 11:32:59 +0100, rick
wrote:

On 7/12/2016 8:45 PM, T i m wrote:
Hi all,

Mum has an old wall mounted, low capacity, b/f conventional gas boiler
and she's trying to keep it running till she revamps the kitchen.

It works fine (for what she needs anyway) but now and again the
overtemp stat trips, even though the main stat is set quite low and
I've never see it other than just 'ticking along'.


Suggest putting in a system cleaner run it for a week then flush .. may
just be sludged up

Yeah, as mentioned elsewhere Rick we did that no so long ago when Mum
had the bathroom re-vamped and considering how old the system was it
was pretty clean.

This was one of the ground floor pipes where I fitted a drain cock.

https://dl.dropboxusercontent.com/u/...ain%20cock.png

There used to be one that came out thought the air brick under the
kitchen door (it used to open straight onto the garden, now into the
lean-to) but was 'lost' when it was converted from a gravity system
with a floor mounted coal boiler to a wall mounted jobby (not by me).

This was from the days when they made stuff to last (this is a rad
valve).

https://dl.dropboxusercontent.com/u/...op%20valve.png

Huge bore pipes, all generally pretty clean and little sign of sludge
or calcium build up (but not saying there was none).

That said, nothing to stop me flushing it again and as mentioned
elsewhere, I might take some temperature measurements as the most
narrow part is where the pipes spilt at the return in the heat
exchanger and go though the heat exchanger itself. I should be able to
measure the temperatures of the flow on both paths and see if they are
particularly different.

Cheers, T i m