Intermittent H/Water Worcester bosch 280

[briwiths]

When hot water is demanded from taps/showers (Combination Boiler) it keeps going hot and cold. I have had the WB engineers out three times now and although they have changed many parts including exchangers, pump, diverter valve, and it works OK for a while it always reverts back to intermittent. The engineer says it's scale but I have put in de-scaler/cleaner into the system on two different occasions.
If its going to be a new boiler (hope not!!) how can I guarantee that it won't happen to the new one.

 

[fitz1]

Cant remember exactly but i had similar problem on a worcester , cause was a lazy pump. but that model had 2 pumps. 1 for heating. 1 for hot water.

 

[briwiths]

pump has been changed. No difference.

 

[Plumbmaster]

When hot water is demanded from taps/showers (Combination Boiler) it keeps going hot and cold. I have had the WB engineers out three times now and although they have changed many parts including exchangers, pump, diverter valve, and it works OK for a while it always reverts back to intermittent. The engineer says it's scale but I have put in de-scaler/cleaner into the system on two different occasions.
If its going to be a new boiler (hope not!!) how can I guarantee that it won't happen to the new one.

A good start would be to power flush the system, which is immensely more effective than putting in these sludge removers. Sometimes in an old property the buildup of debris in the system, and the disturbance thereof when the system is circulating, constantly causes problems with either the radiators or the boiler itself.
In any event, should you eventually have to change the boiler, this will be a Manufacturer's recommendation prior to installation.
If the boiler is under warranty don't let them get away with it and demand a replacement!!
Good Luck!

 

[briwiths]

I have paid out the original £230 call out charge and still having this problem. Can the boiler be flushed out or cleaned in any way?
Is it advisable to take each and every radiator off and flush out?
What's the best way to power flush and could it be done by a layman ie. me who has a plumber friend??

 

[Plumbmaster]

I have paid out the original £230 call out charge and still having this problem. Can the boiler be flushed out or cleaned in any way?
Is it advisable to take each and every radiator off and flush out?
What's the best way to power flush and could it be done by a layman ie. me who has a plumber friend??

1. How old is the boiler?
2. Power flushing is to the whole system and needs to performed with the correct equipment. Your plumber friend will be familiar with the operation, but if you're going to do it, make sure you do it properly and thoroughly. 3. If the manufacturer's agent has already charged you £230.00 (how long ago?) you should require his re-attendance. Seems reasonable I'd say.
Good luck!

 

[briwiths]

Engineer has re-attended and come to the conclusion, after changing the second heat exchanger with no success, that the back plate of the boiler is blocked with scale and has deemed it un-repairable. Has advised to power flush system and install new boiler.
How easy is it to power flush the system???
What capacity boiler is required. Was thinking of a Worcester Bosch 3.0CDI Combi? Only one bathroom but three floors and 17 radiators, although five of these are tiny ones.

 

[Plumbmaster]

Engineer has re-attended and come to the conclusion, after changing the second heat exchanger with no success, that the back plate of the boiler is blocked with scale and has deemed it un-repairable. Has advised to power flush system and install new boiler.
How easy is it to power flush the system???
What capacity boiler is required. Was thinking of a Worcester Bosch 3.0CDI Combi? Only one bathroom but three floors and 17 radiators, although five of these are tiny ones.

The power flush should be performed with the correct equipment and chemicals as recommended by the manufacturer. Ask a professional to do it as the boiler will operate more efficiently and within Warranty conditions.
Boiler capacity required is dependent on house volume to be heated - ask advice from a pro.
17 rads sounds a lot. If you're serious about getting the place in really good shape you may consider replacing these. If you do the power flushing becomes less important as most of the sludge will be in the radiators.
Worcester Bosch is a very well respected Brand.