Potterton Suprima 40 - Tripping and cold radiators

Mickyl1005 · 5 Jan 2008

I have a Potterton Suprima 40, which is giving me no end of problems. Currently the boiler will fire up, but after a period of time, there are loud banging noises in the pipes leading to boiler. It then trips itself out...

When it continues to run for a while, the radiators remain cold although the bathroom one heats up slightly. I still get hot water...I have bled all the rads but I still think from the noises I have air in the main pipes leading to my boiler....

Can someone help me to solve the prob. Any help would be appreciated....

Mick

kirkgas · 5 Jan 2008

sounds like poor circulation is causing the boiler to overheat and be noisy, check the pump is running then check the motorised valve for the heating side is opening

Mickyl1005 · 5 Jan 2008

Thanks for this, the pump doesn't make a noise when the heating is turned on, it is set to speed '2' - I'm not sure how to check the motorised valve for the heating side is open??

I have piping hot water, but the clanging on the pipes seem to be getting louder and the boiler tends to make a hissing noise before tripping out.

Cheers

Mick

superdupergasman · 5 Jan 2008

Sounds like you pump is U/S.

check you have got 240vac before changing it though!

bab · 5 Jan 2008

sounds like a 3 port midposition valve with a knackerd motor stuck in dhw position. Has ya zonevalve got three pipes to it in a T shape.?

possum_jenkins · 5 Jan 2008

yeah agree with the above, sounds like pump failing, heat not getting away, boiler goin to overheat.

bengasman · 5 Jan 2008

Turn pump to max
Isolate your cylinder one way or the other.
Start with running ch and dhw independent
Turn all the rads off bar one and see if it warms up top and bottom in the middle
If you have cold spots in the rad, system needs cleaning; most open vents do

Mickyl1005 · 5 Jan 2008

The pump is a Myson Compact CP93. Zone valve isn't T shaped, it has a single pipe with tap going into bottom and top of pump.

I was going to try taking the plastic cap from the middle of the pump and trying to bleed pump, but it sounds like I need a new pump? Dya think there is anything I could do manually before I call someone in?

Cheers

Mick

Mickyl1005 · 5 Jan 2008

Cheers Bengasman;

So I turn pump to '3'?

How do I isolate cylinder and run CH & DHW independent?

bab · 5 Jan 2008

can u post a pic of ya pump & zonevalve. if ya hot waters very hot ya pump must be working a little unless ya immersions on.

bengasman · 6 Jan 2008

Simplest way is to override the timer for ch or dhw, though not all timers allow for that.
With a bit of luck you have a valve inline with the inlet or outlet of the coil; the two pipes on the side of the cylinder about halfway. Close it completely for the test.
A bit more work and a bit more complicated if the former fail is to remove the actuator and move the spindle manually. If you try it this way, make absolutely sure you remove only the screws for the head otherwise you open the valve itself, gets rather wet if you do it wrong

ChrisR · 6 Jan 2008

The HW could be heating by gravity (convective) circulation.

Turn the ch on and move the pump speed selectore from 1 to 3 and back etc. It should be prety obvious if it's turning, as it stops between the settings.
Also, if you remove the central screw (dribbles) and insert a screwdriver it's be obvious if the shaft's sturning. If it isn't try to engage said screwdriver into the end of the shaft (not easy sometimes) and turn the pump. Does it turn?

bengasman · 6 Jan 2008

ah yes, i keep forgetting there are still gravity systems around. could well be this is one of 'em. howe many m/v's do you have?

Mickyl1005 · 6 Jan 2008

Thanks;

I shall try to post pic of pump. I have tried testing both the HW & CH separately by closing each tap at the side of the pump sequentially. I closed off all of the rads except for the main one in living room downstairs.

The one rad left open remained stone cold. I have checked the pump and it is making no whirring noise at all - even when I switch on CH manually, run upstairs and moved it between speeds 1 & 3 there seemed to be nothing at all.

I shall try taking out the centre piece of the pump as pointed out in the earlier posts.

Thanks all for the help.

Mick

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Potterton Suprima 40 - Tripping and cold radiators

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