Vaillant Ecomax 824 - C.H Fine No Hot Water

[sabgerry]

Hi Guys new to this site so please bear with me. Having problems with Vaillant 824 combi for over a week now. Central Heating works fine but we are getting no hot water. Had the diverter valve and p.c.b changed at great cost by a so called CORGI fitter, all to no avail. He is at a loss now at what it could be. PCB not recording any faults and diagnostic codes d.22 = 0 and d.35 = 1 when a hot water tap is switched on. Any ideas!!!

 

[chrishutt]

What do the status codes show when you put the hot water on?

 

[sabgerry]

Hi. Boiler stays on S.24 which is Burner ignited (warm start) with the C symbol flashing on and off

 

[chrishutt]

And is the burner ignited? If so, where is the heat going? If it's going into the hot water heat exchanger you would be getting hot water. Is it going instead into the CH pipes? In which case the diverter valve is not doing its job.

 

[sabgerry]

The burner is igniting and the two 22mm pipes of the heat exchanger appear to be hot but the 15mm hot water outlet goes cold very quickly. As mentioned he has put a new diverter valve on and has also tried swapping the electric solenoid from the old valve, still no joy. Neither valve appears to be stuck. As you can see I am at a loss.

 

[chrishutt]

Well if the primary (CH) side of the heat exchanger is hot but the hot water side cold at normal flow rates the heat exchanger is not working - possibly clogged up with corrosion deposits from CH system that should have been flushed out when boiler was installed.

Suggest you find yourself a competent boiler engineer.

 

[Agile]

Clogging of the DHW HE is a relatively gradual occurance if the system has not been disturbed. It would usually take several weeks!

Careful questioning of the user is essential to know what to look for.

Its simple to diagnose! Excessive temperature gradient across the primary of the secondary HE !!!

Why did you apparently pay for parts to be fitted which were unnecessary?

Tony

 

[sabgerry]

The Heat Exhanger has been cleaned out and appears to be flowing freely on both sides.When you put yourself in the hands of so called Corgi registerd experts you would expect them to know what they are doing. Obviously not as I have found to my great expense. I will just have to bite the bullet and see what another Engineer has to say. Thanks for everyones assistance.

 

[chrishutt]

When you put yourself in the hands of so called Corgi registerd experts you would expect them to know what they are doing.

Corgi registration is based on having a certain degree of competence in relation to gas safety. It does not imply any expertise in relation to boiler fault diagnosis, which is a specialised area. It might be helpful to you and others if domestic boiler engineers could be indentified by some specific qualification.

 

[Agile]

If only you had said where you were, we might be able to suggest someone in your area who would be able to identify the fault.

Just a few seconds feeling the temperature of the various pipes in the boiler will give a competent engineer the answer!

Tony

 

[Stephen hall]

I've just solved this issue with my ecomax 824/2e... I had already replaced the divertor valve, cleaned and descaled the secondary exchanger and then replaced the pcb... These didn't solve the problem.
Today I replaced the NTS sensor and removed the pipe work with the flexi hose in the middle of it that goes to the main heat exchanger. It was full of gunk and had reduced bore, after a good clean out and refit everything is working perfectly.