Hot water issues with Vaillant EcoTec Pro 28 combi boiler

[derekocon]

I have a Eco Tec Pro 28 boiler - it's about 5 years old.

A couple of weeks back we started having issues with the hot water supply from the boiler - when the hot tap is opened we get hot water as expected but within 1-2 minutes the temperature starts to drop off and then starts running cold. If I turn off the hot water and then turn it back on again the same thing happens. The central heating is working 100% fine - no issues at all.

I have a British gas service contract and they've recently made 2 visits to try to sort out the problem. The engineer initially thought that the system was full of 'gunk' and cleaned some of the internal workings such as the plate heat exchanger. This made no difference. They've since replaced the exchanger on the assumption that it's performance was being impacted by the 'gunk' in the system, but again this hasn't resolved the issue. They recommended that we fit a magna-booster filter, which I have for a cost of £280, and are also talking about the problem potentially being with the main heat exchanger, however this seems unlikely given that the heating is working fine. They've also recommended a Power Flush, which I may consider in the future as a means of basic hygiene for the system but I can't see how this will resolve the issue at hand.

Has anyone got any thoughts on what the issue could be? Apparently the sensors were recently replaced on the boiler too so between all the servicing and part replacement recently the kit should be almost as good as new.

Thanks

 

[Agile]

A Magna thing for £280!

You really do pay for your allegiance to BG !

I could have supplied and fitted one for about £184 !

Its difficult to guess at boiler faults over the internet. The only place to make a diagnosis is at the boiler.

I do not expect it would be difficult to identify the fault but people working for BG are not always that bright!

Tony

 

[GavThePlumber]

British Gas have properly ripped you off, that much is clear.

 

[derekocon]

A Magna thing for £280!

You really do pay for your allegiance to BG !

I could have supplied and fitted one for about £184 !

Its difficult to guess at boiler faults over the internet. The only place to make a diagnosis is at the boiler.

I do not expect it would be difficult to identify the fault but people working for BG are not always that bright!

Tony

Thanks for confirming what I had already thought. Its safe to say that I wont be using them for any other services after they've managed to get this boiler back on its feet...if they can manage that.

I have another BG engineer here at the moment - he's been running the hot tap for about 30 mins. He says it fires up fine to full temperature, then modulates back down but doesn't come back up again.

 

[Agile]

He is expected to know his job!

That model has excellent diagnostic readouts.

How excellent his diagnostic skills are remains to be seen. Please keep us posted.

If BG fail then they seem to have a procedure where they can call a makers staff engineer to assist them ( meaning to show them whats wrong! ).

Tony

 

[derekocon]

So after spending 3 full days trying to solve the problem it turned out to be an issue with the pump. BG replaced the pump after speaking with Vaillant and it's working perfectly again. This comes after they replaced the plate heat exchanger, the pipes feeding this, and the sensors.

 

[Bunnyman]

I'm sorry I suspect u will be back on here very soon

 

[Mikefromlondon]

if it was the pump, central heating ran perfect din't it, I bet its your DV.

 

[derekocon]

I'm sorry I suspect u will be back on here very soon

You were right. The problem has returned. Interestingly the hot water works fine when the pressure in the hot water tap is low, e.g. tap is 1/4 open but once the demand is increased the temperature tails off and doesn't warm up again. Very bizarre.

 

[derekocon]

He is expected to know his job!

That model has excellent diagnostic readouts.

How excellent his diagnostic skills are remains to be seen. Please keep us posted.

If BG fail then they seem to have a procedure where they can call a makers staff engineer to assist them ( meaning to show them whats wrong! ).

Tony

The problem has returned! Hot water works fine at low pressure but when the tap is opened beyond 1/4 open the water heats up, modulates down and never comes back up to temperature. At this stage they have replaced the pump, plate exchanger, and pipes feeding the plate exchanger. Any ideas what the problem could be?

 

[Bunnyman]

Difficult without seeing it but it couldnt be any of yhe things they changed suspect divertor / and pcb fault (usually both) or blocked cAnoefilter

 

[Steelmasons]

I wonder did they clean/replace hoses?

 

[derekocon]

Difficult without seeing it but it couldnt be any of yhe things they changed suspect divertor / and pcb fault (usually both) or blocked cAnoefilter

I had another BG engineer on site today to investigate this ongoing boiler issue. They've now told me that the issue is with the primary heat exchanger, and that they'll only replace it if I first pay them £720 to perform a Power Flush. If I was to get a Power Flush performed independently and more cheaply (approx. £400) they say that they won't cover the cost of replacing the heat exchanger as they can't guarantee the work...this sounds like BS to me.

I'm fairly certain that there is nothing in the terms and conditions of the Home Care contract that would require me to have a Power Flush performed before boiler maintenance is performed, and I'm also fairly certain that they're clutching at straws by saying that the primary heat exchanger is bust...bearing in mind that the central heating is working absolutely perfectly, and the hot water works fine when the tap is operating at low pressure. They've replaced pretty much all other parts of the boiler at this stage and in my mind are pulling a fast one and trying to recoup some of their outlay to date.

I'd love to hear from some heating engineers who could a) confirm my suspicions about the heat exchanger being ok, and b) advise of the symptoms that generally need to be shown to indicate that a closed system needs a Power Flush.

Thanks in advance.

 

[derekocon]

A Magna thing for £280!

You really do pay for your allegiance to BG !

I could have supplied and fitted one for about £184 !

Its difficult to guess at boiler faults over the internet. The only place to make a diagnosis is at the boiler.

I do not expect it would be difficult to identify the fault but people working for BG are not always that bright!

Tony

See the latest update below...all advice appreciated!

 

[Gas2Air]

It's the hose, left of boiler inside, they do become partially blocked. A flush isn't required at all, although they may know that this is blocking and are using the BG get out. Have this changed and the canoe filter checked first before considering a flush.