Vokera 25HE fan not running (not fan problem)

[davinci]

Hi
This is a new install and when DHW or heating is selected the pump starts but then the fan does not and hence there is no further action. I have tested the fan by feeding 240V direct to it. I also tested the PCB by using a link applied to appropriate IC pins to activate fan relay (relay operates and fan then runs).

All flowchart tests indicate PCB fault but the bPCB has been replaced and the same fault occurs. Red blinking LED after initial green blinking LED is the only visible diagnostic. The green LED blinks as it should when on standby.

According to manual pins 8.3 and 8.5 on PCB should have 24V when DHW or CH active but meter shows only 5V. This does suggest a PCB defect but I don't believe two PCBs with the same fault.

DPS connectors show 17Kohm on 20K meter range with switch open circuit (mains off). Could the DPS be the cause? Or is there a pump running sensor which imay be inoperative? I do not think that the fan running is dependent on the pump running but perhaps this is a fail safe?

 

[picasso]

if its a new install why doesnt the installer contact vokera for an in warranty repair ?

 

[davinci]

The boiler was obtained from a local agent as a boxed "package" to replace an existing Vokera, allegedly as a direct replacement, same supply arrangements and pipe centres. Due to delays on other works in this flat refurbishment and other projects the box did not get opened for three years. At this point the boiler was past warranty and the supplier had ceased trading. It also became apparent that the supply arrangements were very different from the original Vokera so the pipes had to be ripped out and rerouted. Being a condensing boiler the new one also needed a direct drain for condensate etc. And by the time that had been done a further year had passed before the boiler was even connected up.

I then had a local RGI in to connect up the gas and inspect the installation which was all good except that the damn thing would not run its fan ...

The local guy does not normally do Vokera and does not want to know about PCB replacements etc. He wanted me to bin it and put in a Worcester but I was not keen to abandon what looks like a perfectly good boiler especially as the pipework would have to be changed again. So I just left it for another two years while attending to other things. Now I am back at it and have replaced the PCB and repeated the troubleshooting described. I am sure there is something trivial causing this issue but I can't find it. If I get no useful advice from here then I'll just have to get a Vokera agent in and stump up for a non-warranty repair.

 

[neiln]

Hi

From the info you have given the boiler can,t have been commissioned by the RGI and shouldn't have been left connected to the gas.

Get a RGI to fix it is my advice.

 

[nickso]

I'll just have to get a Vokera agent in and stump up for a non-warranty repair.

i would do that in this instance.

even if you got the correct advice on here you are still not going to have a properly commisioned appliance.

 

[davinci]

I found the fault - with help from Justanswer.com, although even the Volera engineer assisting did not actually propose the eventual fix!

It has a thermal cut-out on the MASTER OVERHEAT THERMAL SWITCH which is not automatically reset. When I pulled this from its mounting inside the burner case I saw a tiny red push button between the spade connectors. I pressed this in and it clicked. The overheat switch then went from open circuit to closed and everything worked. I am posting this to assist anyone who may have the same problem as this cut-out is not shown in the service manual circuit diagrams and is not mentioned in the troubleshooting charts. If the troubleshooting charts are followed while this cut-out is tripped then they indicate a PCB fault which is a false result.

This boiler was in this state right out of the box from the factory. I assume they stress test this on the production line to ensure that the overheat cut-out works, and should reset it after the test. In this case it was not reset and I had the misfortune to be faced with this when doing the preparatory work prior to my Vokera guy doing the commissioning and sign-off. Now I just need to find a Gas-Safe engineer to come and do the final set up and sign the book.

 

[joe-90]

Which he won't do as he didn't install it nor fix the boiler to the wall.

 

[Agile]

You are clearly someone who is very mean and does your utmost to avoid paying anything!

It is inappropriate to advise anyone who is not gas registered to open the combustion chamber.

No RGI should sign off any installation which he has not made himself.

Tony

 

[sherl]

hi thanks for your advice about the thermal cut out switch, my boiler had broken down found the switch located on the right hand sidebehind the inspection cover and pressed it back in then boiler worked fine, just like to ad i am not an engineer so to all boiler engineers who tried to fix it theres job vacancies at asda for shopping trolley engineers you cant go wrong

I found the fault - with help from Justanswer.com, although even the Volera engineer assisting did not actually propose the eventual fix!

It has a thermal cut-out on the MASTER OVERHEAT THERMAL SWITCH which is not automatically reset. When I pulled this from its mounting inside the burner case I saw a tiny red push button between the spade connectors. I pressed this in and it clicked. The overheat switch then went from open circuit to closed and everything worked. I am posting this to assist anyone who may have the same problem as this cut-out is not shown in the service manual circuit diagrams and is not mentioned in the troubleshooting charts. If the troubleshooting charts are followed while this cut-out is tripped then they indicate a PCB fault which is a false result.

This boiler was in this state right out of the box from the factory. I assume they stress test this on the production line to ensure that the overheat cut-out works, and should reset it after the test. In this case it was not reset and I had the misfortune to be faced with this when doing the preparatory work prior to my Vokera guy doing the commissioning and sign-off. Now I just need to find a Gas-Safe engineer to come and do the final set up and sign the book.

 

[Dabat#]

Thanks for this post. I had the exact same problem. Unfortunately I bought a new pcb for 200 notes before I found this. I reset the thermal switch as described nd it worked great. I think vokera are shocking to have misleading fault finding information in there manuals.

 

[vulcancontinental]

What tosh. Unless you are gas safe registered engineer you should not remove the casing of the boiler to even find the button, it's tucked in there for a reason. If you are a gas safe engineer you should know what you're looking for and where to find it. A gas safe engineer if you had called one could have fixed that in a few minutes saving your guessing costing you £200. I can't be bothered to check but think if you look in the user information part of the manual you'd see the LED lights explained and the remedial measures to be taken there.

 

[Hot&Cold]

I think vokera are shocking to have misleading fault finding information in there manuals

They and many other manufactures literature offer guidance only, knowledge & detailed onsite fault finding with accurate measuring equipment is essential.

£200 pcb

 

[Dabat#]

lesson learnt for me then,,,,

 

[vulcancontinental]

Hope I wasn't too harsh, try to sell the board on eBay.

 

[ffernan2@jaguarlandr]

Hi, I'm facing the same issue with my Vokera Mynute 24m. However, after I press the Thermal switch we use the boiler, next time I need to press the Thermal switch again, because it will be tripped. Anyone faced it?