worcester 24cdi issue. Not confident with engineer

[johnoldinho]

Hi

I recently had an issue with my Worcester boiler, it was heating all the radiators every time the hot water was used.
I had an engineer out and he replaced the diverter valve, not before trying to sell me a brand new boiler...

This has now caused the hot water to go from hot to cold every 30 seconds. Could anyone advise me on what the problem could be? Could this be the engineer trying to get me to buy a new boiler, as it didn't haven this issue before the new part was put in?

Any help would be greatly appreciated.

 

[McCombi]

I suspect your domestic water heat exchanger needs to be cleaned with chemicals or replaced. This couls also cause the diverter valve to pass so the engineer may very well have been correct.

 

[Agile]

Heating rads during DHW useage is a diverter valve fault.

However, if the plate heat exchanger is well blocked, the excessive back pressure can also make the diverter valve to leak heat to therads.

The exact cause is not that easy to dianose so replacing the diverter valve would be the remedy that a lot of engineers would choose.

Only then would they discover the plate heat excahnger is blocked and needs cleaning or replacing.

The boiler will stay on while the diverter valve is leaking. When that stops leaking after being replaced, the boiler needs to turn to turn the burner off. Theburner cycling then causes the hot/cold effect to te hot water.

Tony

 

[Boilerman2]

Your Engineer was probalby not incorrect in suggesting a new more efficient boiler as sadly with many especially Combi's it only takes two or three major parts, to render the boiler "beyond economical repair" - trouble is without a crystal ball, it is often difficult to see the final outcome

 

[johnoldinho]

Thanks very much for your responses, they have definitely re-affirmed my confidence with my engineer.

Before I pay for another call-out, is there anything I could try that could potentially solve this problem? Obviously nothing too major, but I've seen people mentioning flushing and cleaning the heat exchanger... Is this something that I could DIY?

 

[Agile]

Many people do manage to clean them as a DIY.

But that depends on your skill level.

Becase the blocked plate was a pre existing fault at the time of the last visit the engineer, in my view, should not charge much to return to clean the plate.

Tony

 

[McCombi]

As mentioned unless you're very handy with fiddly diy I wouldnt attempt it yourself.

These boilers can spring many leaks and the manifolds surrounding the problem area can also crumble away when disturbed, personally I think you would be better off getting a fixed price repair.

Whatever you do, make sure the heating and hot water are both tested before the engineer leaves.

 

[FiremanT]

.

Becase the blocked plate was a pre existing fault at the time of the last visit the engineer, in my view, should not charge much to return to clean the plate.

You weren't there, Tony, so it isn't fair to wind up or raise a customers expectations in this regard. It isn't even clear whether any re-contact has been made with the plumber.

OP: I would recommend talking to the plumber to ascertain his perceived position. My PERSOMAL approach on this type of thing is to continue to charge my standard timed rate, but not charge any callout or initial fee. Having said that, I a totally clear with my conditions before even knocking on your door. I always try to mention any potential issues such as this before we start.

 

[Agile]

I always explain the possibilities to the customer at the beginning and any limitations on the treatment proposed and even give budgetary costs involved.

Very unfortunately, many say oh yes its this or that and never consider the possibility that there are further faults or deficiencies.

Customers are also not always blameless! They will usually choose an engineer who says its the cheapest fault. Unfortunately because I mention ALL the problems they then go t someone else. Luckily they often come back to me when they find the cheap guy has not solved the problem!

Tony

 

[TCCHeating]

Your heating engineer diagnosed the correct prob at the time so credit to him.

Was your hot water going hot/cold before the divertor valve prob heating the rads with hot water on? If it only happened after a new dv maybe an other prob? As i cant see the plate heat exchanger getting blocked in such a short time. My guess is whilst changing the divertor valve some debris has been caught in plate heat ex?

 

[Agile]

My expectation is that the plate was already blocked and the old diverter valve was allowing some heat to the rads!

The new diverter valve stopped the leak to the rads and the boiler is now turning on/off because it cannot dissipate the heat as before.

Tony