Recent content by JohnC51

Final one of this episode - having consulted a local Corgi chap, the boiler is fine, the MPV was stuck in the almost water off position, hence the need for bypass if the heating was off as there was insufficient flow through the water heating coil to dissipate the heat from the boiler. The...

Erk! On my system (installed by previous owner at least 15 years ago) the flow is on the left and the return on the right. That would explain a few things! Any idea where I can get hold of a manual for one of these boilers (Glow-worm 45F)? I've tried the GW web site without success...

Hi again Chris, The oveheat stat does look like a thermocouple - the copper tube is tightly coiled at the end resembling a spring. I didn't remove it from the sheath around the return pipe but it was loose inside and there was evidence of some heat compound similar to that used mounting...

See my thread "Water boiling in the heating system" as I too have concerns about bypass valves - mine is manual and without it my system would have blown by now. I have seen Glow-worm instructions stating that a bypass is a "must-have" and that it should never be closed under any circumstances...

Update - Having looked inside my Glow-worm Fuelsaver 45F, the stat is in the return pipe, as is the overheat stat thermocouple.

OK - I've just been inside the boiler ... the thermostat DOES sit in the return pipe which explains why the flow water can get so damn hot. If I didn't open the bypass the return wouldn't heat up quick enough to shut the boiler off, hence the "boiling" problem. (I got the wrong part from the...

ChrisR, Thanks for that - sorry if I sounded impatient in previous posts, these plumbing jobs get my nerves jangling, especially on a Sunday! Hopefully the thermostat replacement won't prove too challenging! Cheers, John

No response to my previous posting so perhaps a simple question may provoke an answer :?: Does the boiler thermostat control the temperature of the Flow or Return water? Thanks in anticipation that someone out there knows the answer.

I have a Glow-worm fuelsaver F boiler, Myson Aerjec auto-venting thingy and a Honeywell MPV which is stuck in the mid-position. There is also a manual bypass valve. With the boiler stat set on 2 (out of 6) and with the bypass valve almost shut the water boils up through the Aerjec vent. With...