Potterton Profile Prima 80e air pressure switch

[cujimmy]

My potterton Profile Prima 80e was not firing up. I traced it to a faulty air pressue switch which I replaced. It will now work ok for a day or so, then stops working again, and when I check with my multimeter, the pressure switch has not reset.

I've removed the exhaust bend and checked the tubes and the fan which are all ok. There is a restrictor in the bottom tube to the pressure switch, which I can blow through (Just ! )

I now think I should replace this restrictor and both the red & clear tube to the switch, as the red tube has a bit of a kink in it, and I'm not sure about the restrictor.

What do you think of this idea ??

 

[Agile]

You seem to be doing all the right things.

However this is a positive pressure case model and has certain possible dangers and so work on it should only be done by a CORGI registered engineer.

It would be unwise of me to attempt to give you any further advice in the circumstances.

Tony Glazier

 

[cujimmy]

Thanks Tony.

Not wishing to tar all CORGI engineers with the same brush, but going on past experience where my wife had to call in BG afterwards, I'm VERY wary of letting anyone near my system, but I hear what you're saying.

Just to give you a wee bit of background, I'm an maintenance Electrician by trade, and have been working on all sorts of control systems for all of my working life. I worked on oil & gas platforms offshore, so I'm WELL aware of the dangers of gas (and at much higher pressures than here - 1500 psi, for example)

I've found a link to a site with all the Potterton and GC part numbers, so I've now got a list of the bits I need. Where would you suggest as the best place to order them on line ??

Many Thanks
Jimmy

 

[Agile]

The restrictor as you call it is in fact a pneumatic inductor which together with the volume of the tube between the restrictor and the APS produces a smoothing circuit with a time constant of about 2-3 seconds.

It is unlikely that this is causing your problem if you can see through the small hole.

Tony Glazier

 

[ChrisR]

I just wonder if you've been tempted to "try out" the air switch by blowing into it? It's very possible to overstrain them doing that, after which , if they work, they can stick.

 

[cujimmy]

Thanks again Tony for your reply.
I'm not sure about "seeing" through the hole in the restrictor, but I did try blowing through it after removing it from the tube. Last night I took a very fine piece of copper wire and poked it through, as I was a bit concerned that, being a very small hole, the moisture in my breath may have clogged it up. Anyway, it hasn't stopped since, but I still intend to replace it and both the clear & red tubes as after 12 or so years, they are probably past their "sell by" dates.

Chris,
I didn't blow in the switch, but I did blow through the tubes & pipes from the exhaust elbow to ensure that they were clear. Last night I disconnected them from the switch and ****ched on the boiler (when it was still hot), and let the fan just blow some air through for 5 mins or so.
BTW, must be a bit cold in Antartica! What do you use for heating there?

Many thanks to you both for your input

Jimmy