Alpha CB24 boiler problem
Discussion
Hi all,
I'm away at work at the minute and my other half has said there is no water pressure at the hot tap. None coming through upstairs but we have a low flow downstairs, the temperature is normal.
I've read the user manual and it appears that the pump is borked, when the hot tap is turned on the light illuminates as if everything was working correctly.
Do these CB24 boilers have a common fault or failures I should look at getting the parts for? I'm happy with doing the plumbing side of it but don't want to be on a wild goose chase if it would be best to get an engineer out.
Any help is much appreciate.
Dave!
I'm away at work at the minute and my other half has said there is no water pressure at the hot tap. None coming through upstairs but we have a low flow downstairs, the temperature is normal.
I've read the user manual and it appears that the pump is borked, when the hot tap is turned on the light illuminates as if everything was working correctly.
Do these CB24 boilers have a common fault or failures I should look at getting the parts for? I'm happy with doing the plumbing side of it but don't want to be on a wild goose chase if it would be best to get an engineer out.
Any help is much appreciate.
Dave!
Sounds like a divertor valve block, the rubber part inside perish's and can sometimes restrict the flow.
They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Wish you well Dave.
They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Wish you well Dave.
xllifts said:
Sounds like a divertor valve block, the rubber part inside perish's and can sometimes restrict the flow.
They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Really?? But all these things are on the primary heating side, not the domestic? Granted I've only ever been involved with two Alpha boilers, but they seemed to work like any other combination boiler?? They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Festive Ferg said:
xllifts said:
Sounds like a divertor valve block, the rubber part inside perish's and can sometimes restrict the flow.
They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Really?? But all these things are on the primary heating side, not the domestic? Granted I've only ever been involved with two Alpha boilers, but they seemed to work like any other combination boiler?? They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Baffled our plumber for a while but we did the above and it worked only my personal experience though.
xllifts said:
Sounds like a divertor valve block, the rubber part inside perish's and can sometimes restrict the flow.
They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Wish you well Dave.
This.They are about £80 from Time and temperature in Bognor regis and they will deliver, they are on google.
Have you got good pressure in the system as that will also cause flow problems should read 0.7 - 1.0 bar when cold, you should have a flexi pipe underneath where you can top up if needs be but do not overfill!!
If it is low pressure keep an eye on it after refilling as it may well drop again, if so it is more than likely to be your expansion vessel leaking causing loss of pressure.
You can re-pressure the vessel but would recommend a plumber to do that as it is a PITA on the CB24 especially if its fitted within 400mm of ceiling.
Wish you well Dave.
I have a CB24 and the diverter valve failed. I could either get got water or heating by manually messing with the valve. Dont waste your time trying to repair it (i tried!) just get a new diverter valve and seal kit.
It is a horrible job and good luck getting it to seal again, quite a lot of joints to undo.
Had mixed opinions on this from a few heating engineers, i am seriously thinking about replacing my whole boiler soon with a worcester.
Can't see a diverter valve causing low flow from the hot tap, low temperature perhaps.
I worked on a CB28 yesterday and it seemed to have the standard diverter and plate heat exchanger set up.
IIRC there is a left and right hand manifold on these, could possibly be a blockage in one of these.
Check that the cold inlet isolation valve isn't partly shut, some engineers do this when there are issues with the hot water temperature, which these Alphas suffer from. Its possible work may have been done on the water mains and allowed dirt into the system, which could block a partially closed valve.
I worked on a CB28 yesterday and it seemed to have the standard diverter and plate heat exchanger set up.
IIRC there is a left and right hand manifold on these, could possibly be a blockage in one of these.
Check that the cold inlet isolation valve isn't partly shut, some engineers do this when there are issues with the hot water temperature, which these Alphas suffer from. Its possible work may have been done on the water mains and allowed dirt into the system, which could block a partially closed valve.
Thanks for all the replies guys, much appreciated.
It never came to me to have the missus check the cold water pressure aswell, which was just the same as the hot. It is now all back to normal so i'm guessing there was a problem with the street, the panic of possibly no heating over christmas is over.
Although it will be going in the summer for a new boiler I think i'll give it a check over, new seals and filters checked, valves etc as I just have zero faith in it.
Thanks again for the replies.
Dave!
It never came to me to have the missus check the cold water pressure aswell, which was just the same as the hot. It is now all back to normal so i'm guessing there was a problem with the street, the panic of possibly no heating over christmas is over.
Although it will be going in the summer for a new boiler I think i'll give it a check over, new seals and filters checked, valves etc as I just have zero faith in it.
Thanks again for the replies.
Dave!
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