Lukewarm dhw from Vokera combi

[drood]

Hi,

Having read dozens of posts here, I am fairly sure that the cause of my lukewarm dhw is the diverter valve on my Vokera Syntesi. Can anyone tell me which actual part/parts I need to replace? Is it the motorized valve (R2905) or the 3-way overhaul kit (R01005127) or something else? The manual is not particularly clear!

Thanks in advance.

 

[Agile]

You may be sure but I would not be.

A blocked secondary heat exchanger is the most popular problem.

Like all boiler faults it needs properly diagnosing!

Tony

 

[drood]

Thanks for the reply, Tony.

I have already had the DHW heat exchanger out and flushed it through. It wasn't very dirty or blocked up. Put it back and exactly the same symptoms, so have now moved to the diverter idea. Would it be worth just cleaning the components before swapping it out? There are no fault codes which suggests it isn't a thermostat problem.

 

[Dan Robinson]

 

[drood]

???????????

 

[Dan Robinson]

Have a think and post back.

 

[gigz]

Turn you heating off, then turn your h/w tap on and feel the flow pipe (heating), does the heating pipe get hot ? Have you tried slowing the tap down ?

 

[Agile]

Thanks for the reply, Tony.

I have already had the DHW heat exchanger out and flushed it through. It wasn't very dirty or blocked up. Put it back and exactly the same symptoms, so have now moved to the diverter idea. Would it be worth just cleaning the components before swapping it out? There are no fault codes which suggests it isn't a thermostat problem.

What is this thermostat?

 

[drood]

That's what Vokera Technical Services said to me on the phone:
Him: "Are there any fault codes?"
Me: "No."
Him: "Oh, it can't be your thermostats then."

In the words of Manuel, "I know nothiiiiing". I came on here to try and get a bit of help, since another board had hinted the diverter valve problem, but if no-one knows, it doesn't really matter. I'm sure I'll work it out sooner or later.

 

[drood]

Turn you heating off, then turn your h/w tap on and feel the flow pipe (heating), does the heating pipe get hot ? Have you tried slowing the tap down ?

Hi Gigz,

When I turn the hot tap on the water heats to about 36 degrees on the boiler. Temp does not change if I slow the tap flow down. Flow is good. There does not appear to be any difference from before this issue started a couple of months ago - just that no longer have piping hot water.

I tried your suggestion and yes the CH flow gets very hot as soon as I turn the tap off and the temp on the front of the boiler jumps to 65+, beofre gradually descreasing.

 

[Agile]

Boiler faults do really need to be diagnosed at the boiler. That's why no one here can "know" what is wrong with your boiler.

Based on what you have said it may be a blocked plate HE ( or a blockage in the path to it. )

It can also be a PCB failed.

Or even a wrongly set or faulty gas valve. But DIYers cannot measure gas parameters.

I know the general feeling is that "plumbers" are thick because they left school at 15 but there can often be a lot of skill and knowledge involved in diagnosing faults.

Did you ever find a "thermostat" mentioned in the service manual?

Tony

 

[Agile]

When I turn the hot tap on the water heats to about 36 degrees on the boiler. Temp does not change if I slow the tap flow down. Flow is good. There does not appear to be any difference from before this issue started a couple of months ago - just that no longer have piping hot water.

How did you measure that temperature?

Tony

 

[drood]

36 was the temperature displayed on the front of the boiler. BTW, I haven't suggested that plumbers are thick, not sure where that one came from.

 

[Agile]

Expecting that people here can diagnose a boiler fault from an internet site without comprehensive technical operational data ( to include gas pressure measurements ) implies that you think that boiler repairs are very simple and can be done by almost anyone.

Anyone who "tells" you what is wrong from the information given above is simply guessing in the full knowledge that he is not taking any liability at all for what he is saying.

That's the case even in respect of a very simple boiler like yours.

Tony

 

[drood]

Just checked the manual - there is a thermostat attached to the front of the main burner, and a limit thermostat on the pipe from the heating manifold to the primary heat exchanger.