potterton profile questions

[littlelegsal]

Hi all,
I've been having the strangest problem with my profile 50e. A lovely boiler I must say but the firing sequence is driving me nuts. Most of the time it fires without a problem but every now and then the fan would run and no firing will occur. After much research and air flow pipe checking etc i changed the aps with it still seems to happen every now and then. the only coincidence seeming to link the events is that its normally between 6 and 7 at night. Volt stick lights on the white wire but not on orange showing aps connection is being asked for. Sometimes a sharp tap on the aps works or if i blow down the red pipe. later in the evening all is running fine again. I'm sure the time thing must just be a coincidence but it seems to always be around this time it happens.

Also does anyone know whether the red system selection switch should be up or down for a fully pumped system. All manuals I've found say it should be set in the correct position but all neglect to say which this is and its not written on the boiler.

Many thanks from a first time poster long time reader.

 

[gaswizzard]

If you look at the switch an arrow will indicate gravity or fully pumped.

If you've already replaced the air proving switch you would of noticed a small brass restrictor which is used to join the two air tubes together.

 

[littlelegsal]

Hi gaswizzard thanks for such a speedy reply.

is the arrow on the red part of the switch? Have taken a torch and a magnifying glass to it and I may be able to just make out the very faded remains of an "up" arrow but I may just be seeing things. If I am actually seeing it does this mean I do indeed want the switch down thus revealing this arrow meaning I'm on the pumped setting?

As for the brass restrictor, I have one roughly an inch into the clear outlet tube which in "coned" away from the switch and clear of debris. Is this the one you mean? Doesn't seem to be actually joining any tubes though.

 

[Agile]

View media item 41092
I think that its pretty clear that the switch should be down for fully pumped.

Tony

 

[Agile]

We dont give advice on this forum on gas or combustion related aspects.

On just this particular model the APS can be replaced by a DIYer in theory but he would be unable to measure the pressure applied to the switch from each tube.

Are you able to accurately measure the mains voltage between 6-7 and compare it with mains at other times of day/night ?

Tony

 

[littlelegsal]

Cheers Tony that picture is perfect. Thought mine must be missing a sticker, I shall put one on now.

I changed the aps only because it is not in the actual sealed part of the boiler and I thought maybe the other one was sticking now and then and you're right I can measure the strength of air flowing down the red pipe as it almost undetectable it seems - I presumed this is one reason for the restrictor after the switch. I did notice on the removed switch that it can be adjusted but this is something I wouldn't do myself as I thought the part comes preset? If this does sometimes need adjusting I'll gas an RGI in. Could this be the case or does it normally come preset?

I did think about the mains voltage but admittedly haven't tested it yet as the fan runs and mostly a short tap on the aps would make the boiler fire. I'll test it next time I find the fan running alone again and report.

 

[45yearsagasman]

I presumed this is one reason for the restrictor after the switch.The restrictor has the effect of extending the prepurge time and neither that or the APS should be adjusted.

 

[littlelegsal]

I thought/hoped they shouldn't be adjusted.
Thank you

 

[Agile]

The restrictor provides a delay before the switch operates and possibly also prevents short term drop outs or activation caused by excessive gusts of wind on days like today.

The switch contacts on those APS can become high resistance when old.

The operate point does not usually drift and is accurately set on the screw and then sealed.

What does reduce is the applied pressure created by the fan due to dirt, old age of the fan etc. Thats why measuring the applied pressure is important to correctly identify the problem on a particular boiler. The tubes also stretch and harden and can leak too.

The switch operates at only 0.4 mBar which is a gentle wind! The applied differential pressure is about 1.2 mBar so there is a good excess of pressure in a boiler in good condition. It can only be measured by a sensitive digital manometer. Mine does two decimal points.

Measuring the fan speed is also something that I would do in a problem situation as thats another aspect which its useful to know about.

Most of these aspects need a boiler engineer as they can open the combustion chamber and may have the appropriate testing equipment.

Tony

 

[mysteryman]

I had a Profile with a dry soldered joint on the pcb, causing this problem.

 

[Agile]

I had a Profile with a dry soldered joint on the pcb, causing this problem.

I am surprised you did not replace it with a Viessmann!

Last night this German lady asked me to suggest a replacement boiler for a Profile in a flat she was renting out but now wants to sell.

I suggested a Viessmann or an Intergas. She had not heard of either but now I have to look at the relative prices and I think the Intergas is probably a bit cheaper for the system version than the Viessmann OV.

Normally she is very concerned about spending money but with this flat she has no concerns as she wants it to be very smart so it attracts the best price.

Tony

 

[littlelegsal]

hi Tony.



Well after two years of pig headedly not wanting to believe it could be a voltage problem as I didn't think it would run at all with low voltage and I was just well too stubborn to prove myself right I am happy to say I found it Idling and checked the voltage. At first I was getting just under 200 and now an hour later I'm getting 185. What a jipp!! My electric company are sending me low voltage and charging me full price. Briefly it went up to 213 and the boiler worked which I guess is why I was having such an seemingly random and unrelated series of failings. Not saying this is a conspiracy but I wonder if anyone else on my street is having these problems.- Since watching so many war movies over Christmas I'm am pretty sure it's either the Russians or more likely the Germans who are behind it somehow.



Well I wasted 50 quid on a new aps but at least I finally found you to give me a kick up the backside and check the voltage properly rather than lazily with a volt stick. Gonna get on the phone to the thieving gits right away.

Thanks again.

 

[littlelegsal]

Electric company coming out tomorrow for a good telling off. Can't believe its finally gonna get sorted. Took me two winters of torment trying to link the vents all together but I got there in the end. Hallelujah

P.S. Anyone wanna buy a second hand (but in perfect working order) switch for a profile 50e