Vokera Vision combi boiler

[GingerSparkQ1]

Looking to see where I went wrong and see why I made a mess of things.

I was asked to install a Hive onto a Vokera Vision 30C combi boiler.

I turn up, 3 core from FCU to hive receiver (LNE) and then a 5 core flex from the receiver to the boiler (LNE and 1&3 from inside the receiver) and inside the boiler the standard LNE and take the link out of the connector block on the left hand-side and connect 1&3 to the connector block.

Turn on the FCU and everything is fine. I call for hot water and bang, MCB trips, PCB board scorched. No fuses inside on the PCB blown though.

Can anyone explain if possible the heck I did wrong? I am expecting a rough time, but I want to understand where I went wrong so don’t just the p**s out of me.

I now have to pay for this to be fixed but I want to know what I did wrong. I’m even brave enough to admit I have to pay another guy to fix it now.

I have added a picture of the pcb board before I wrecked it.

 

[UNG]

If you have wired it as described then the only way I can see why this occurred is you have used a 2 channel Hive receiver and put 240v up the 24v control side

I'm a bit confused by the call for hot water and it went bang when this is a combi boiler, exactly how did you call for hot water was this by turning a hot tap on

 

[GingerSparkQ1]

Yup, turned the water on and bang.

Wasn’t a 2 channel hive receiver. I checked that before I took it out the box.

 

[Zerax]

Can you show a pic of the 'scorched' board too ?

So is the PCB definitely knackered and the boiler is no longer working ?

 

[GingerSparkQ1]

Don’t have the pic. But I have marked on the pic where the burnt marks where.

I disconnected my stuff, rigged it back up the original way and the boiler came back on. But no hot water or heating now.

Customer got proper p***ed off and called BG to come out. Which is fair enough I don’t blame them at all, especially when it’s been freezing. But I have tried to phone and text to see what they are saying and how much it’s going to cost and no reply from them now.

 

[Zerax]

I agree with UNG then... somehow you've managed to put 230v across the 'no volt' thermostat connection. Unless the boiler was already like that before you started ? How did you wire up the receiver ?

I managed to knock out a boiler PCB a few weeks ago... just by turning it off and back on again ! They can be delicate things !

 

[GingerSparkQ1]

I must have done something to blow the pcb. The receiver was LNE and 1&3 connections. I must have done or touched something that’s caused it. But was just to see if anyone knew offa hand with the little info I have or incase I was doing the connections wrong.

Out of curiosity Zerax, what did you do when you done that to the pcb? Did they manage to get heating and hot water still or what?

 

[Zerax]

Out of curiosity Zerax, what did you do when you done that to the pcb? Did they manage to get heating and hot water still or what?

The board was as dead as dodo... even though there was power getting to it and both board fuses were intact. I was rather stressed, so I called a plumber mate of mine (well, when I say mate, I know him...) who calmed me down. He told me that it's remarkably common, especially on Alpha boilers ! Luckily the homeowners were very understanding and trusted me when I explained it to them, so I didn't get stung with repair costs. (£220 for a new PCB !). They actually seemed happy that it happened whilst I was there to diagnose the faulty board and swap it out for them !

 

[UNG]

Yup, turned the water on and bang.

Wasn’t a 2 channel hive receiver. I checked that before I took it out the box.

Did you check it after you took it out of the box, never assume what it says on the box is what is actually in the box

Don’t have the pic. But I have marked on the pic where the burnt marks where.

I disconnected my stuff, rigged it back up the original way and the boiler came back on. But no hot water or heating now.

Customer got proper p***ed off and called BG to come out. Which is fair enough I don’t blame them at all, especially when it’s been freezing. But I have tried to phone and text to see what they are saying and how much it’s going to cost and no reply from them now.

Can't find a decent wiring diagram for that boiler but the burn at the top of the board looks to be where the hive / thermostat ultimately connects via the smaller PCB on the left which looks to be the digital display in the diagram I have. As for the one at the bottom of the PCB the diagram doesn't give enough info to speculate on what caused that burn

When you were removing the Hive receiver did you do any analysis of the possible cause as other than a crossed connection or short on the 5 core it has to be the hive at fault.
Strangely with the single channel Hive no where in the instructions does it state the the control contact is volt free, although it does have common, heating off (nc) and heating on (no) connections which suggests it should be
I don't suppose you have the Hive unit and 5 core cable so you could test it to identify where the problem lies

 

[loz2754]

Hive and boiler manuals attached if this helps.

 

[UNG]

Hive and boiler manuals attached if this helps.

Same diagrams I've already looked at

 

[GingerSparkQ1]

Thanks for the helps guys.

UNG ... I did have a look and couldn’t see anything but I must have done something to cause the damage. Unless I have touched something or crossed something over and never realised. Either way, looks to be my fault I reckon.

The home owner got back to me saying BG came out, said I nearly caused a fire, all my connections were wrong (even though I disconnected all my connections and reinstated the original ones which was only LNE and the link) - which I doubled checked before I left and that I shouldn’t have been in the boiler connections as I’m probably not gas safe reregistered, to which the are reporting me for.

So things get worse.

I take responsibility for screwing the pcb, but I have never heard of having to be gas safety registered for connecting up a boiler. I always thought as long as you didn’t touch anything gas or air tight it was fine?

So I’m off boilers now. Any one recommend a training course or something? Will ask about my area see if any guys who mainly do them will let me tag a long for my own understanding.

 

[Zerax]

Really sorry to hear about your boiler nightmare... but don't take it too seriously, just put it down to experience.

I'd largely ignore what BG say... they'll obviously try to 'big-up' themselves and belittle anyone else who may have created the problem they were there to fix.

I'm the same with boilers... I hate switching them off/on just in case it goes wrong. I have a specific clause about this in my Ts&Cs now.

 

[UNG]

Thanks for the helps guys.

UNG ... I did have a look and couldn’t see anything but I must have done something to cause the damage. Unless I have touched something or crossed something over and never realised. Either way, looks to be my fault I reckon.

The home owner got back to me saying BG came out, said I nearly caused a fire, all my connections were wrong (even though I disconnected all my connections and reinstated the original ones which was only LNE and the link) - which I doubled checked before I left and that I shouldn’t have been in the boiler connections as I’m probably not gas safe reregistered, to which the are reporting me for.

So things get worse.

I take responsibility for screwing the pcb, but I have never heard of having to be gas safety registered for connecting up a boiler. I always thought as long as you didn’t touch anything gas or air tight it was fine?

So I’m off boilers now. Any one recommend a training course or something? Will ask about my area see if any guys who mainly do them will let me tag a long for my own understanding.

Sounds like typical BG surprised the guy didn't try to sell the homeowner a rewire while he was there because the boiler wiring was dodgy

 

[plugsandsparks]

I am gas safe and electrical, FWIW, indeed the Hive 1,3 terms are supposed to be NV contacts, which you use to control the thermostat connections inside the boiler.
On the face of it i cannot see where this would not work.

The BG guy probably didn't like the cable from FSU to Hive and then to boiler, but thats just semantics.

Its also possible you were very unlucky, its not clear whether the PCB blew on call for DHW or whether than just coincided with a call for CH,

Either way you either wired it wrong, i.e. not as you have described or you were unlucky and the PCB blew because it had been powered down. It really does happen (alot)

BG guy can report if he wants but you are authorised to make those connections, so gas safe / HSE will probably ignore.

I understand why you may wish to avoid boilers, for me, if that happened i would have simply replaced the PCB, re-tested appliance and moved on.

It may be worthwhile, if you want to connect Hive's and the like, to know a gas safe buddy who you can call under these circumstances.

Hope this helps

P&S