Combi boiler and hot water problem

Michelle2014

We have a nearly 10 year old combi boiler. No problems with the boiler until now. The hot water has not been very hot recently (eg baths with solely hot water) and also quite inconsistent eg hot then cold etc. We called in the boiler company for a service and asked about the hot water and they said it was the plate heat exchanger (apparently is was full of limescale). The engineer took out the plate heat exchanger and tried to clean it. A couple of days later we asked the same company about getting a repair and protect plan from the same company. Their office now seems to be suggesting we need to get our system power flushed before we could take out their warranty plan. It's now been a few days since the service was carried out and the situation with the hot water has deteoriated and we are now hardly getting any hot water.

I would be grateful for any advice on what to do next - does this sound like our system needs power flushing? Will replacing the plate heat exchanger solve our issues with the hot water? As the boiler is 10 years old in July should we be thinking about replacing the boiler?

colin79666

Power flushing the central heating system will remove sludge (mostly rust) but won't stop a limescale build up from the mains water supply for the hot water.

10 years is ok for a boiler so replacement depends on the health of the rest of the system really. If everything else is fine then I'd be temped to try a repair as you could well get another 5-10 years out the boiler if it is serviced annually.

southcoastrgi

Run the hot water tap, feel the flow pipe to the heating under the boiler does it get hot ?

Michelle2014

colin79666 wrote: »

Power flushing the central heating system will remove sludge (mostly rust) but won't stop a limescale build up from the mains water supply for the hot water.

10 years is ok for a boiler so replacement depends on the health of the rest of the system really. If everything else is fine then I'd be temped to try a repair as you could well get another 5-10 years out the boiler if it is serviced annually.

Thanks for the reply. The engineer said it was in really good condition. We rarely use the central heating (as we live in a superwarm flat!) so 99% of the time just used for hot water. Tested the heating today and it is working fine.

Spoke to British Gas today and they also said about powerflushing the system because of the limescale issue.

Michelle2014

southcoastrgi wrote: »

Run the hot water tap, feel the flow pipe to the heating under the boiler does it get hot ?

No the central heating pipe does not get hot.

southcoastrgi

Power flushing won't remove any lime scale in the plate heat exchanger if that is the problem

macman

Michelle2014 wrote: »

Thanks for the reply. The engineer said it was in really good condition. We rarely use the central heating (as we live in a superwarm flat!) so 99% of the time just used for hot water. Tested the heating today and it is working fine.

Spoke to British Gas today and they also said about powerflushing the system because of the limescale issue.

Doh! A powerflush just deals with the closed CH circuit, and has nothing to do with the mains side, which is unaffected by a powerflush.
This is just BG trying to flog their grossly overpriced powerflush, as usual. Get a proper RGI in who knows how to do fault diagnosis.
Has the divertor valve been checked?

Michelle2014

macman wrote: »

Doh! A powerflush just deals with the closed CH circuit, and has nothing to do with the mains side, which is unaffected by a powerflush.
This is just BG trying to flog their grossly overpriced powerflush, as usual. Get a proper RGI in who knows how to do fault diagnosis.
Has the divertor valve been checked?

So we had the boiler company back out today and they have replaced the heat exchanger and we now have hot water! The engineer has said he doesn't know why the office started mentioning powerflushing to us as it's not something we need.

Thanks to those who replied, really helpful.