no dhw during operation of boiler,boiler fires when central heating on ok.dhw none, know the bascis changed diaphram and then changed mixer valve but pin on the diaphram still dosent come out approx 11mm..stripped valve and all is very free moving, do i need another divertor valve as i got two seconhand ones now.any help woiuld be gratefull.
grant combi no dhw
- Thread starter john3565
- Start date
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John,
Try watching the pin while you adjust the thermostatic mixing valve. Maybe you need a little more flow to push the diaphragm over. You can also remove the screw that holds the plastic knob onto the mixer valve, turn the knob round and refit it in a different position to give more range of movement.
Try watching the pin while you adjust the thermostatic mixing valve. Maybe you need a little more flow to push the diaphragm over. You can also remove the screw that holds the plastic knob onto the mixer valve, turn the knob round and refit it in a different position to give more range of movement.
beleive it or not but tried that at 1am last night.you know when things pop into your mind.no luck with moving the knob,tried even to short the switch to ensure pump came on to push hot round but no good,could the divertor valve itself be sticking in centraql heating mode all time,is there a way to sort out valve as got a spare second hand one now as well.cheers john
John,
The burner should have at least fired up when you shorted out the microswitch. Did it?
The burner should have at least fired up when you shorted out the microswitch. Did it?
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John,
I've been looking through my manual to see what it could be. There isn't much to the diverter valve really, it's usually the diaphragm that splits but you've already renewed that. (There is a small valve on the inlet pipe to the diverter valve, you haven't accidently turned that off?)
If the burner fires up when you short out the switch, likewise the pump for the other switch then it looks like a water flow problem. Water pressure OK otherwise? It could be your plate heat exchanger blocked. It happens a lot in hard water areas where it gets blocked with limescale but I think that your water is OK (ish?).
Perhaps you might like to speak to Grant technical, 01380-736920.
I've been looking through my manual to see what it could be. There isn't much to the diverter valve really, it's usually the diaphragm that splits but you've already renewed that. (There is a small valve on the inlet pipe to the diverter valve, you haven't accidently turned that off?)
If the burner fires up when you short out the switch, likewise the pump for the other switch then it looks like a water flow problem. Water pressure OK otherwise? It could be your plate heat exchanger blocked. It happens a lot in hard water areas where it gets blocked with limescale but I think that your water is OK (ish?).
Perhaps you might like to speak to Grant technical, 01380-736920.
another diaphram free from supplier as all pointed to divertor valve but expensive and was free to move.and fitted,all working fine now,can see a slmall hole in the supposed new silicone diaphram.informed supplier and he is going to refund me.the information gained has helped heaps,great site recommend to others
many thanks john
Well done John. Holes in the diaphragm can be difficult to spot. ( I usually thread a piece of paper through the hole to show the customer.) Bad luck getting a new one with a hole in though!!!!
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