Halstead Finest (Wickes) 90 Safety lockout issue

[Musicmac]

I've had the above boiler 10 years fine but now giving me real trouble. I have searched everywhere for similar problems (but similar is not the same) and have followed advice i've found.

CH runs for expected time and switches off for a while, then fan (not burner) turns on and safety lockout lights and fan keeps running 'forever'. If i switch off at the mains for about 30 minutes and switch back on then fine, but same problem occurs. If I don't wait that long then powering up just gives me the lockout and fan (with ch and hw off). HW on it's own does not appear to cause the problem, but I don't run HW for very long, however if heating has been on and then I use hw the lockout occurs shortly. The overheat sensor (pushbutton underneath) does not trip. Pressure stays between 1 and 1.4 Bar.

All radiators get hot fast when functioning - I do think they are a bit hot even though the heating 'dial' is set to minimum.

I have so far had two (one halstead suggested) engineers who have not been able to fix the problem. The Halstead Tech line (now Dimplex I think) can't help over the phone and have given me another engineer to call.

So far this is what has been done;

Cleaned Venturi and fan (all very clean anyhow). Fan works fine.

Replaced Flow diverter assembly (there was a sticking switch actuator) The original was also really clean inside and I could have fixed the original it turns out - shame.

Removed heat exhanger - and was clear of sludge (I use CH protector)

Replaced thermisters on the diverter assembly.

Replaced PCB (shame - same problem).

Checked pump function.

Checked for air and bled everything.

Checked solenoid function on gas flow modulator and gas pressure.

Checked wiring continuity where possible.

Checked flue for obtructions - clear.

If I run CH for five minutes every 15 minutes everything is fine but I can't do that forever.

Both engineers have given up. This has cost £350 already and have gotten nowhere. If anyone has any suggestions as to what to look for next that would be great. This is driving me nuts, as I can't think of anything else to do/get done to fix this .

Any help much appreciated. Thanks in advance. Dave.

 

[Musicmac]

Problem was due to two things.

First was pump giving up slowly which reduced water flow and increased temperature. It was the pump itsself that was cutting out or seizing due to the temperature therefore switching the primary flow switch off when it stopped. It takes a long time to 'reset'. I thought it was the pcb/thermistor and not the pump but I was wrong.

Second is the air proving switch. I bypassed it and it got things working for a while (pump still on way out). I have new pump, but still need the bypass on the air proving switch. Venturi fine - very good flow, air pump clean as.. I got 4 months left with this boiler and am for the moment happy with bypassing the APS. If air isn't right then nothing big can happen in fact damp squib really.

I just got a little niggle with the Boiler front panel control. What is the Heating dial for? 'User instructions' are to set to max, but nowhere have I ever found an explanation as to what the hell it is there for and what it does. As it happens I've never noticed any difference between min and max on either of the rotary dials. On my installation they seem to do nothing. I expected perhaps a variation of the thermistor resistance trips but I've not seen anything in practice.

Any ideas would be appreciated.

Thanks to AndyR for pointing me in a few good directions. Also helped me realise that 'old style' heating engineers tend not to have a clue about modern 'chip' based systems. I could have saved a lot of money by doing it myself (water side).

Regards, Dave.

 

[Agile]

Well you clearly think that you are very clever at fixing boilers.

I think that you are very stupid because you have bypassed a safety device but you will not realise how dangerous that is because you dont have enough understanding of how boilers operate.

For HALF of the £350 you spent on engineers who could not diagnose the fault ( and who should NEVER have charged anything! ) I could have come and diagnosed what was wrong.

Tony

 

[Musicmac]

Thanks for that Tony.

I appreciate that you may be better than the (three) engineers who came out (referred by halstead).

The advice regarding the air proving switch was from these forums as a 'temporary' measure to find the fault.

Advice from an ARGI engineer who replaced the pump suggests that not much can happen as a result of my temporary 'fix'. In the meantime I have functioning heating. I appreciate your comment about 'safety device' however this has all been well advised and nothing has been done without such advice or professional assistance.

Kindest regards, Dave.

 

[bengasman]

...and am for the moment happy with bypassing the APS. If air isn't right then nothing big can happen in fact damp squib really.

Nothing big can happen?

To get a rough idea about how dangerous this is:
If I found this in a boiler, I would have to report this to HSE; not doing so would put my gas license at risk.

If GSR found out that I bypassed an aps, I'd most likely loose my license there and then.

You have disabled a device that is there to prevent an explosion under fault conditions. The kind of fault condition that could very well happen with your boiler.

What you have done puts the safety of you, your family and your house at risk.

 

[Agile]

Thanks for that Tony.

The advice regarding the air proving switch was from these forums as a 'temporary' measure to find the fault.

Kindest regards, Dave.

Can you provide a link to where that advice was given on a forum?

Tony

 

[bengasman]

...The advice regarding the air proving switch was from these forums as a 'temporary' measure to find the fault....

Stuff like this is the very reason why most of us don't give safety critical advise any more.

Bypassing safety devices should only be done by a qualified professional who knows what to watch out for, AS A TEST!!!
It is absolutely not acceptable to do this for any other purpose than a test, and only for the duration of that test.

 

[Musicmac]

Reason given for the APS bypass is like this ;

It is there to prove air flow to the boiler (in this system a bi-directional flow to make sure that it flows in both directions) which is determined by a differential pressure between the two venturi feeds.

If one or other is blocked, or the air pump has failed then the boiler will lock out. Fine and understood - all good.

If any of the above occur then due to other saftety measures the lockout will occur anyway. No flame - lockout - there will be no gas supply if the initial fireup fails, and it will fail immediately if there is an air-flow problem. Overheat - lockout. This is as explained to me so far and clarified as a result of your posts.

If you people can explain to me why this is so dangerous then I will certainly reconsider. I am not a risk taker. The fault is with the switch and not the flow. I have already said that the air-flow is excellent and verified - manometer.

I have no-one living at this house apart from me a few days a week. Not that that is justification for doing anything dangerous.

You should find the note by googling 'Halstead finest 90 air proving switch' thats how I found it.

Regards, Dave.

 

[bengasman]

If you people can explain to me why this is so dangerous then I will certainly reconsider. I am not a risk taker.

If the fact that finding a safety device bypass is a compulsory RIDDOR and report to HSE does not give you an idea of how dangerous your alteration is, there is really not much more to explain that will make you understand how irresponsible you are acting.

It is on a par with those that get in the car after 8 pints, because they don't have to drive far and they will go slow anyway, so it is ok.

 

[Musicmac]

I guess I should also mention that the heating is totally off when I am not here. As I say I am not a risk taker. I understand that a leaf getting past the intake guard could cause trouble, but I always check, and the other safety devices should take care of that as well - or tell me I'm wrong. At the end of the day I've just been following advice from 'professionals'. I feel people are criticising me for doing what I been advised!

Regards, Dave.

 

[Musicmac]

bengasman, would you please just explain what the issue is. I will pass it on and sort it out! Just blindly saying it is dangerous does not help. Tell me what the issue is! You are not being helpful. I am asking you to help me! Not just make comments without explanation.

Regards, Dave.

 

[bengasman]

...At the end of the day I've just been following advice from 'professionals'. I feel people are criticising me for doing what I been advised!...

Did you miss the bit about ONLY as a test, FOR THE DURATION of the test, and done by a qualified professional?

Does the fact that if I was caught leaving a boiler working after I had bypassed the aps I would loose my license to work on gas, not tell you anything?

If you still don't get it, I can only see two options here.
1. This is a wind up. ( I hope it is)
2. Your are a dangerous psychopath.

Either way, giving you any further attention is pointless.

 

[Musicmac]

Ok bengasman. Sorry to have troubled you. Perhaps someone else will be able to explain why this bypass is dangerous. That is all I need to get it fixed.

Thanks. Dave.

 

[Musicmac]

Please understand I am not asking for justification for this fix or anything like it. I need to know what is WRONG with it and potential problems with it! I have absolutely no interest in justifying it. I want to know what harm it could do. If anyone is able to tell me then please do - then I'll pass it on and get it fixed.

An engineers licence in this forum is totally irrelevant to anything unless you are giving unsound advice I guess. The post I found about the bypass was with a rider - only temporary. I accept that and will for the moment (until told otherwise) consider my fix temporary. I don't want to know what a licenced engineer would have to do, and at this stage seems irrelevant as I have not heard a thing telling me what the problem might be with doing this. All I need is explanation of why this is dangerous.

Kindest regards to all. Dave.

 

[Corgigrouch]

Musicmac.... If you really need an explanation, then sadly no explanation is possible