Diverter valve on Vaillant EcoTec 824

[squowse]

Hi, hope someone can help or comment on my diagnostics
1) Hot Water is cold
2) Central Heating fires up OK.
3) When Hot water is switched on, the boiler fires up but the heat goes to the CH circuit.
4) I diagnose that the diverter valve is not operating correctly and not diverting heat to the HW heat exchanger.
5) The on board diagnostic D.35 (position of diverter valve) changes from 0 (CH position) to 100 (HW position) when the hot water tap is switched on.
6) I am thinking that the diagnostic is reading wrongly and the diverter valve is stuck, but the diagnostic is sensing a different part of the mechanism that IS moving.

My question is - are the electrical connections to the diverter valve just for the diagnostic facility/feedback to the PCB or is it actually actuated electronically. I think these would have been totally mechanical originally?

I would like to proceed with servicing/replacing the diverter valve but the more info I have about it the better I think.

My background is I am a civil engineer and quite techy. I am reasonably competent in plumbing, but not gas certified obviously.

Thanks
Roger

 

[sootydog123]

I replaced the diverter valve on my ecotec however the old diverter valve had some how taken out the pcb so had to replace that as well

I am not a heating engineer btw.

just somebody who used to build things that could take out whole families just the same if they weren't built properly just the same.

 

[squowse]

Thanks for quick response! Can you give me any tips to remove it and refit. I have just bought a new valve.

 

[squowse]

Just an update to finish off the thread for anyone else that might be looking in the future..
The valve is electrically operated so the diagnostic d.35 was reading what the boiler was trying to set it to, not where it was actually set. I did also check the flow rate (diagnostic d.36) and that was reading the flow correctly.

I managed to get it out but needed a 30mm spanner (not an adjustable, they're too big to fit in) to undo a fitting on the CH flow pipe at the front. These are hard to find at 6.30pm on a Saturday! I managed to use a compression fitting spanner from Toolstation, it is 32mm but worked. Apart from that it is 3 screws and 2 clips. It needs to be wobbled out sideways from the pump. It is a lot easier when you have the new on in front of you to see how it fits. The system needs draining down obviously.

After refitting the hot water is now working again.
I could not see anything apparently wrong with the old valve, the plunger was not seized or sticky, likewise the solenoid (actuator). It would have been worth unscrewing the actuator (electricity off!) to see what was wrong. Could have tried the hot water with the actuator unscrewed to see if it moved. I don't think the actuator is sold separately anyway though. Shame as it is far easier to change.

Anyway I am happy just to have fixed it, part no. is 178978, £65 on eBay.

The bypass is also fitted to the diverter valve and the screw on the new on is all the way in, which I am guessing means no bypass. I am getting my plumber round anyway to do a service so he can adjust it correctly and check my work.

 

[The831Bunny]

Actuator 140429 £21 on Fleabay.

 

[squowse]

Yes I saw that but it looks different to the one I have here. Not listed as compatible either. And not on the vaillant spare parts diagram.

 

[The831Bunny]

That sort of info is only available from using an engineer who is experienced with Vaillant appliances. You can't expect DIYers to have that knowledge. Fair play to you, but there's plenty more to check and adjust while a professional is on the job.

 

[squowse]

Don't give away all your trade secrets....

 

[The831Bunny]

Nothing secret, all available in the Manufacturers instructions and The Gas Safety (Installation and Use) Regulations 1998.

 

[sootydog123]

Actuator 140429 £21 on Fleabay.

How much would a time served Boiler engineer charge to fit this part?

 

[Boilerman2]

Of course the OP has no idea that your username 831 Bunny actually refers to you be a bit of a Vaillant Specialist!

 

[Bunnyman]

Yes mr831 ur a specialist!