Hi everyone,
I've been trying to solve a short-cycling DHW problem on my Microgenus II 31 MFI (NON HE).
I had a spare pump so I changed that first - no difference.
I then noticed that the bypass pipe was getting super hot so decided that it was likely that the original 18 year old secondary/plate heat exchanger must be clogged/scaled and ordered a replacement. Fitted the new one but it didn't change anything.
That leaves me with the diverter valve. I noticed it was weeping slightly out of the top so needs changing anyway. I only replaced this one in Feb 2020 so it hasn't lasted well - possibly as it was a £15 eBay repair kit - the same as I ordered to fix it with.
Anyway, I've come to remove the cartridge and it is stuck fast. I was using my large adjustable spanner as the head of the cartridge didn't look suitable for a socket set, and anyway my largest socket is 27mm and was too small.
I debated whether to go and buy a socket that would fit, but decided to try again with the spanner. More fool me. I steadily applied pressure and felt what I thought was the cartridge beginning to move. It wasn't - the soft brass cap was shearing at the top. I stopped as soon as I realised this and so it is still water-tight.
I refilled and tested the boiler in DHW - still works as the valve defaults to DHW (although still short-cycling obviously). Because the cartridge top is now oval, I can't get the actuator on so I won't have CH until this is resolved, but can afford to wait as clearly I don't need CH right now.
What is the best way to proceed with this? As the cap is now warped, I've got no chance with a socket. Would push lock/water pump pliers be better?
Also, I did this while the valve assembly was hot. Would it come off more easily when cold? Finally, can I apply grease to the threads on the new one to help prevent future sticking or would that affect the water-tightness?
Thanks for any tips - pic of valve below...
I've been trying to solve a short-cycling DHW problem on my Microgenus II 31 MFI (NON HE).
I had a spare pump so I changed that first - no difference.
I then noticed that the bypass pipe was getting super hot so decided that it was likely that the original 18 year old secondary/plate heat exchanger must be clogged/scaled and ordered a replacement. Fitted the new one but it didn't change anything.
That leaves me with the diverter valve. I noticed it was weeping slightly out of the top so needs changing anyway. I only replaced this one in Feb 2020 so it hasn't lasted well - possibly as it was a £15 eBay repair kit - the same as I ordered to fix it with.
Anyway, I've come to remove the cartridge and it is stuck fast. I was using my large adjustable spanner as the head of the cartridge didn't look suitable for a socket set, and anyway my largest socket is 27mm and was too small.
I debated whether to go and buy a socket that would fit, but decided to try again with the spanner. More fool me. I steadily applied pressure and felt what I thought was the cartridge beginning to move. It wasn't - the soft brass cap was shearing at the top. I stopped as soon as I realised this and so it is still water-tight.
I refilled and tested the boiler in DHW - still works as the valve defaults to DHW (although still short-cycling obviously). Because the cartridge top is now oval, I can't get the actuator on so I won't have CH until this is resolved, but can afford to wait as clearly I don't need CH right now.
What is the best way to proceed with this? As the cap is now warped, I've got no chance with a socket. Would push lock/water pump pliers be better?
Also, I did this while the valve assembly was hot. Would it come off more easily when cold? Finally, can I apply grease to the threads on the new one to help prevent future sticking or would that affect the water-tightness?
Thanks for any tips - pic of valve below...
