No Call to Boiler- Potterton Suprima 30 and Potterton EP2002

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Hi,

My girlfriends heating has been playing up for a while and I've tried my best but could do with some advice/ideas! HELP!!

She has a Potterton Suprima 30 boiler with a Potterton EP2002. The board inside has been previously changed due to common problems but I don't think it's the boiler that is the problem now.
http://img844.imageshack.us/img844/7164/34808995.jpg
http://img17.imageshack.us/img17/601/38745017.jpg

Intermittently the boiler will turn off and we cannot get the heating back on. The EP2002 is still lit up for the heating but the boiler sits there with light on solid amber (no call to boiler).
http://img197.imageshack.us/img197/7767/41301781.jpg
http://img571.imageshack.us/img571/6817/14002085.jpg
http://img834.imageshack.us/img834/9531/84255980.jpg
I've tested the switched live when we have the problem and there is a small voltage (nowhere near 240v that it has when working), around 90v as pictured
http://img211.imageshack.us/img211/1356/19110949.jpg
..and that changes i think, don't think it's always 90v. Pumped live also has no voltage through it when it isn't working. Live always has 240V

Due to the above I replaced the Potterton EP2002 with a new Potterton EP2002, thinking this was the problem. It is still a problem intermittently problem with the new EP2002 (about 50% of the time it doesn't work). Sometimes the heating will only come on if you turn the water on too, sometimes cutting all power to the boiler and timer and turning back on after a few minutes will make it work, and other times none of this works!

I've checked the thermostat and when it isn't working this also doesn't seem right, it has 3 wires, one neutral, permanent live and switched live (am I right). When we have problems with it there is no permanent going to it.
http://img145.imageshack.us/img145/9923/77370210.jpg
http://img708.imageshack.us/img708/8370/14478857.jpg

I'm guessing the wiring is okay as it does work around half the time, sometime for days at a time (strangely it seems to work for longer when I've messed with the EP2002).
http://img577.imageshack.us/img577/5745/33049256.jpg

ANY help is really appreciated! Currently sitting here warm with the heating on, this could change any minute!

Thanks!

Russ.
 
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I've checked the thermostat and when it isn't working this also doesn't seem right, it has 3 wires, one neutral, permanent live and switched live (am I right). When we have problems with it there is no permanent going to it.

Then your fault is at the programmer somewhere.
is the wire tight in the back plate ?
 
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Then your fault is at the programmer somewhere.
is the wire tight in the back plate ?

Could be Seco but my money is on the end switch in the mid position valve the op has neglected to mention or is unaware he's got
The 90V reading should be a clue ;)
 
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Have a look in the airing cupboard Russ to see if you can see something like this
82rew_1.jpg


Matt
 
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The 90v reading is more likely from the 230v on the grey wire from the hw satisfied/off which will give you around 100v on the orange.
hw satisfied/off, no call for heating.

No power to the stat from the programmer isn't going to get him no where.
 
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The 90v reading is more likely from the 230v on the grey wire from the hw satisfied/off which will give you around 100v on the orange.
hw satisfied/off, no call for heating.

I know,thats my point, and the same is also true when the second micro-switch has failed to make.
To get the 90-100v showing on the orange means that the voltage has to be sourced from somewhere, that means its either derived from the call on the white which means the ch side of the programmer is ok or the grey which also means the ch side off the programmer is ok since the valve has to have powered from the white to a position that makes the first switch to connect in the grey in the first place.
so there must be power from the programmer on the white in either instance,
No power to the stat from the programmer isn't going to get him no where.

true, and no power from the room stat via the valve when the hotwater is satisfied or turned off isnt going to get him anywhere either, it will work on the occasions that the cylinder stat is calling though

I'm just saying,
Its the 90v call he's getting that does it for me, so my moneys on the valve

Matt
 
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Have a look in the airing cupboard Russ to see if you can see something like this
82rew_1.jpg


Matt

Can't see anything like this in the airing cupboard, guessing it is in the loft? Is there a way to work out if this is the problem when I find it?
Thanks for everyone’s messages/help so far.
 
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