Continuous Safety Lockout

[HDPete]

Hi,

My Halstead Finest Gold (apart from being renowned for being a piece of rubbish) keeps going into Safety Lockout.

It normally does it when the pressure drops in the system (once a year). However, I noticed that the fan was running continuously when I was outside near the flu.

I checked the boiler and it's in safety lockout. The pressure is fine (~1.25 bar). I've powered cycled it and left it to cool down (as I seem to recall it overheated once before). However, it still locks out.

Are there any obvious quick checks I can make. I'm fairly good with electrical circuits etc, but not a gas engineer, so only want to do what I'm allowed to do.

This has started today after no aparent reason. There was HW this morning, but now, obviously, there's no HW or Heating (the pregnant wife is well chuffed about that!).

Many thanks
Pete.

 

[Gasguru]

If the fan is running continuously (with no demand) a relay on the board is likely to have arc'd closed.

This will cause the lockout since the fan prooving/air pressure switch test routine will fail.

Alternatively the board is switching the fan on for no reason. I don't think a temperature sensor fault would cause the fan to overun. Normally just the pump is overun after a demand.

 

[ChrisR]

It's usually a simple airflow problem, but does need taking to bits so ...

 

[HDPete]

Thanks!!

Do the relays ever get stuck mechanically (as opposed to electrically). Is it worth giving them a tap?

Anything I can try as a quick fix?

 

[Gasguru]

You could measure the resistance across the fan relay (if you are competent) to confirm the contact status. Most of these Finests are now due for a board anyway...tapping them is just as likley to create another problem.

I don't find the Finest a piece of junk at all. They suffer from venturi faults more than most (there is very little tolerance for debris buildup - design fault) but parts can be expensive (unless recon).

 

[HDPete]

I seem to remember that last time this happened, the engineer blew out some rubber tubes which resolved the problem. Is this the Venturi problem people refer to?

What would an engineer do to fix this (except blow out a tube)? (don't intend to do this myself, but want to be informed so I understand what's being charged for when someone comes out to have a look~).

Cheers
Pete

 

[HDPete]

Erm... chaps... I have just spoken to Halstead Tech Support who were very helpful and advised me to remove the fan and venturi (after explaining what it was I should be looking for).

I made it clear that I was an end user, not an engineer, yet they still suggested that I could go ahead and remove the fan and venturi.

Am I allowed to do that legally?

Thanks
Pete.

 

[ChrisR]

Strictly speaking, no, because you couldn't "prove the effectiveness" of the flue/case seals, or the APS which is a safety device.... See the FAQ on this - it's about the last one at the moment!

Don't call the same guy as last time, because simply blowing tubes out won't do!