Polarity sensitive boiler??

[NozSpark]

Been out to a job to find out why a combi boiler has started to cut out and I have found that the polarity at the CU is reversed:O:O:O:O:O It was only replaced 2 years ago by a reputable.....

The boiler is a Worscester combi (a reasonably old one though!!)

Also found the boiler supply (2.5mm T&E) protected by a B40 MCB!!

Could this be the cause of the fault??

 

[Andy™]

possibly. some boilers do have electronics that can be damaged be reverse polarity (some have a reference to earth on the PCB)

 

[batty]

Been out to a job to find out why a combi boiler has started to cut out and I have found that the polarity at the CU is reversed:O:O:O:O:O It was only replaced 2 years ago by a reputable.....The boiler is a Worscester combi (a reasonably old one though!!)

Also found the boiler supply (2.5mm T&E) protected by a B40 MCB!!

Could this be the cause of the fault??

Noz

How long has it been cutting out.

 

[NozSpark]

It's only been cutting out in the last few days....

and they've had reverse polarity for the last 2 years..................

 

[Andy™]

cutting out in what way?

 

[batty]

It's only been cutting out in the last few days....and they've had reverse polarity for the last 2 years..................

Can't be reverse polarity then.

 

[NozSpark]

I don't know.... it just stops working!!

A plumber said that supply is failing? :| ?:|

But I don't really trust his diagnosis as he completley missed the reverse polarity:| :|

 

[batty]

I don't know.... it just stops working!!A plumber said that supply is failing? :| ?:|

But I don't really trust his diagnosis as he completley missed the reverse polarity:| :|

Run temp lead from somewhere else that will prove whether it is supply or something else.

 

[Andy™]

Run temp lead from somewhere else that will prove whether it is supply or something else.

or just swap polarity to make it right???

 

[batty]

or just swap polarity to make it right???

I thought we decided it could not be polarity.

?:|

 

[Andy™]

I thought we decided it could not be polarity. ?:|

i wouldnt say that just yet... more info needed. may be some electronics have finally failed giving you problems... something that correct polarity may not sort out

 

[NozSpark]

Well, I must say that I fixed the reverse polarity straight away and have left it to see how things go over the next few days...

The client has agreed that I will rewire the circuit if it continues.

 

[ian932]

My money is on the flue fan, when the fan is on its last legs it can start to work intermittently and when it does the boiler will not flash up unless the fan is running.

Is it a Worcester cdi by any chance, if it is does the customer get any of the lights flashing on the front ?

Also if its a combi I take it that the plumber made sure it was pressurised to at least 1bar.

 

[Andy™]

Also if its a combi I take it that the plumber made sure it was pressurised to at least 1bar.

most low pressure valves are set around 0.5bar

 

[ian932]

most low pressure valves are set around 0.5bar

Yeh I know but manufacturers want the units to be set to at least 1bar which is why I put that and not the shut-off threshold which is around 0.5bar anyway I've seen them shutdown at 0.75bar indicated. Thats why you should set 1bar then you know your well above the alleged 0.5bar.

 

[SPECIAL LOCATION]

i wouldnt say that just yet... more info needed. may be some electronics have finally failed giving you problems... something that correct polarity may not sort out

erm.. AC?

 

[SPECIAL LOCATION]

I thought we decided it could not be polarity. ?:|

that would make sense with an AC supply!

 

[Andy™]

erm.. AC?

some boilers have reference to earth on PCB, so can detect wrong polarity. most dont so not normally a problem