Baxi Solo 3 PF50 boiler - Chattering relay fault

[Agile]

Oh, and as a parting shot, I see your beloved poxy Tesco was featured in a very informative TV program called ‘Whistleblower’ last night.

Just to balance the books, the part of that TV program I watched showed a manager in Sainsbury being told that frozen goods were thawing out and refrozen which carries considerable health risks. I did not like to see him smoking either!

Tony

 

[corgiman]

And


on



and



on

and

on


Yawn

gawd you boys dont half have some stamina

 

[underwurlde]

lol. That's what the wife tells me as well.

 

[bobthebender]

lol. That's what the wife tells me as well.

Thats not what she told me

 

[corgiman]

lol. That's what the wife tells me as well.

 

[HENRY1961]

It looks like the same affliction affects my 7 year old Solo 2 PF60.

The problem started several months ago with a few slow switches of the relay.
The capacitor theory holds good in my opinion.
I read there is a pump overrun timer on the primeval electronics of the control board, (It looks like one of my college electronics projects, except If I'd have turned an effort like this in I'd have failed the module).

Several months ago I noticed when the heating demand was off a few slow clicks of a relay could be heard.

I called a Corgi engineer to take a look and it didn't happen for him, typical!
Since then the problem has been getting progressively worse, until today I saw this posting and it suddenly clicked.

I suspect the overrun timer is a simple CR network triggering a time out for the pump relay.
Over a period of time those cheap and nasty low temp Pektor electrolytic capacitors with the sustained heat of the boiler inches above are drying out. (The electrolyte in these capacitors is wet).
As they dry out the capacitance will decrease causing the time constant of the CR network to become shorter and shorter. (Hence the increasing frequency of the relay chatter over time).
I have ordered a board set of capacitors from SEME, overated the Temp (105 Deg C) and DC working Voltage. (63VDC WKG for the 50's and 25VDC WKG for the 10V) Estimated cost is £5.00, New board £120, I smell a rip off Mr Baxi.

By My reckoning there are 7 off 10 microfarad 50VDC
2 off 100 microfarad 50VDC
2 off 47 Microfarad 50VDC
and 1 off 220 Microfarad 10VDC.

A shiny set of new Matsushitas or Mitsumis or similar high quality components should fix the problem.

Like the questionner I am also an experienced electronics engineer working in the aviation industry.

Baxi ought to be ashamed of the apalling quality of this control board, I hope much better attention to detail has been paid in subsequent designs.

 

[Vic Spanner]

Geek

 

[baxpoti]

I am also an experienced electronics engineer working in the aviation industry

Then why not call yourself an Avionics engineer?

 

[Softus]

I am also an experienced electronics engineer working in the aviation industry

Then why not call yourself an Avionics engineer?

Good point. 'Cos doctors who work in the aviation industry call themselves Avionics Doctors. Don't they?

 

[Agile]

I am also an experienced electronics engineer working in the aviation industry

Then why not call yourself an Avionics engineer?

Because an Avionics Engineer is a different job primarily concentrating on the systems which make the plane fly. With a heavy emphasis on hydraulics.

This fellow may well work for a supplier of some of the electronics equipment used in planes. Telecoms, radar, transponders, radio altimeters and last and least passenger entertainment etc.

However, he seems to have forgotten some of his basic electronics design concepts!

An electrolytic capacitor is rated at the capacity at the rated voltage ( usually with plus 20% capacitance value ).

If you then consistently only use that capacitor at a significantly lower voltage then it will reform itself over time to give a higher value which is not what the manufacturer intended.

Tony

 

[Softus]

Baxi ought to be ashamed of the apalling quality of this control board, I hope much better attention to detail has been paid in subsequent designs.

Hm. Given your claimed superior attention to detail, would you care to have another go at the spelling in that last sentence of yours?

 

[underwurlde]

Just tripped across this & just in case anyone is reading...

However, he seems to have forgotten some of his basic electronics design concepts!

An electrolytic capacitor is rated at the capacity at the rated voltage ( usually with plus 20% capacitance value ).

If you then consistently only use that capacitor at a significantly lower voltage then it will reform itself over time to give a higher value which is not wat the manufacturer intended.

Apologies, but that statement is quite wrong. The voltage rating of an electrolytic capacitor merely denotes its MAXIMUM working voltage, a voltage that should NOT therefore be exceeded. Capacitance of electrolytics can indeed change, but this is usually due to ageing and / or stress (due to heat or excessive voltages / ripple) which will always result in a REDUCTION of capacitance. Also some while back, a massive batch of duff capacitors appeared on the market which used 'wrong' electrolyte, but that is another discussion all together.

Cheers,

Andy

 

[Agile]

It seems you dont understand how electrolytics work.

I dont understand how/why you "quote" something I have posted but add in spelling mistakes which were not in the original !

 

[underwurlde]

OK, provide evidence of your statement please. I am an electronics engineer with 20+ years experience and I'm sorry, but what you've stated there is utter and complete nonsense.