Hi guys,
I've got a Glow-worm Ultimate 30c making really loud banging, clanging noises when operating DHW and just after closing it. Apparently it happens also on heating but not as often and while there, I didn't test it long enough on heating to find out.
The flow temperature on the display goes up to 99 deg, burner goes off and DHW turns cold then the boiler fires up again and repeats the cycle. Sometimes it gives up and shows the reset icon.
It looks like there's a blockage causing the boiler to overheat.
It's a 3 year old boiler and water in the central heating system smells of inhibitor and is very clean. Not a black speck in view. So I'd like to rule out any blockage whatsoever due to sludge.
I drained the hex and filled again 3 times in case there was air in the system. This particular boiler has a purge mode which you can select but it also goes through this purge mode automatically when filling up from less than 0.5 bar, so I didn't use the purge mode.
Pump is rotating, plate to plate clean, diverter valve must work as house warms up nicely and there's hot water at the tap, though it gets cold when boiler stops firing. Removed condensate trap and there was deposit inside, so opened main hex and found quite a bit of brown dust. Cleaned that thoroughly.
Checked thermistor resistances. Tried to gas rate on DHW and high mode but got about half the heat input. That makes sense to me as the boiler is not firing consistently for the 2 min due to overheating.
It sounds like there's a physical metallic object inside causing this really loud noise.
How to identify where and what the blockage is?
I've got a Glow-worm Ultimate 30c making really loud banging, clanging noises when operating DHW and just after closing it. Apparently it happens also on heating but not as often and while there, I didn't test it long enough on heating to find out.
The flow temperature on the display goes up to 99 deg, burner goes off and DHW turns cold then the boiler fires up again and repeats the cycle. Sometimes it gives up and shows the reset icon.
It looks like there's a blockage causing the boiler to overheat.
It's a 3 year old boiler and water in the central heating system smells of inhibitor and is very clean. Not a black speck in view. So I'd like to rule out any blockage whatsoever due to sludge.
I drained the hex and filled again 3 times in case there was air in the system. This particular boiler has a purge mode which you can select but it also goes through this purge mode automatically when filling up from less than 0.5 bar, so I didn't use the purge mode.
Pump is rotating, plate to plate clean, diverter valve must work as house warms up nicely and there's hot water at the tap, though it gets cold when boiler stops firing. Removed condensate trap and there was deposit inside, so opened main hex and found quite a bit of brown dust. Cleaned that thoroughly.
Checked thermistor resistances. Tried to gas rate on DHW and high mode but got about half the heat input. That makes sense to me as the boiler is not firing consistently for the 2 min due to overheating.
It sounds like there's a physical metallic object inside causing this really loud noise.
How to identify where and what the blockage is?
