Potterton Profile not communicating properly with programer?

[DanM1980]

Hello,

I am on the hunt for any advice on how to fix my slightly troubled potterton profile 50e CH system. I believe this is a gravity fed fully pumped system.

Recently we had no hot water or heating and I found the pump in the airing cupboard (a myson cp53) had seized, I was able to restart it but it died again a few mins later so I have replaced this pump with the cheap Wilo Smart pump from screwfix. All seems to be working ok now in terms of heating the water, but for some reason we now have the boiler firing and pump running continuously when the programmer (a potterton EP3200) controls (CH and HW) are both set to off!

The boiler also seems to be unresponsive to the timer. The programmer does still seem to switch the 3 port valve fine to CH on or off though and the room thermostat will also influence the 3 port valve position so I think that's working ok. All the lights and screen on the programmer all appear normal and i can hear the relays click when I mover the sliders to on.

I have believe I can rule out the microswitches in the Honeywell 3 port valve as its only a year old, and and I have also disconnected the grey and orange wires (which I beieve relate to the microswitches) from the terminal block in the valve wiring harness and the pump and boiler still run.

We have been living with this just by turning it off at the fused switch next to the programmer in the kitchen and the hot water heating and CH heating are fine. The only way to stop the boiler firing straight up from stone cold is either to remove the front plate off the programmer or turn the boiler stat down to 0. (the pump still runs thou).

I am thinking about asking one of my neighbours if I can try their programmer (housing estate all houses same boiler about 18 yrs old) but feel this is a bit imposing in case I bugger up their system somehow!

Is programmer fail likely? Or is there any possibility this could be frost stat or pump overrun stat fail? I presume as the boiler runs ok the PCB is ok?

Cheers for any advice on what to try next!

Dan

 

[D_Hailsham]

we now have the boiler firing and pump running continuously when the programmer (a potterton EP3200) controls (CH and HW) are both set to off!

Did the problem start when you replaced the pump? If so, are you sure you wired the new pump correctly?

If the spare terminals (A to D) in the EP3200 have been used, have you checked that wires are not touching each other?

I have also disconnected the grey and orange wires (which I believe relate to the microswitches) from the terminal block in the valve wiring harness and the pump and boiler still run.

Is that with the boiler OFF at the programmer (No HW and No CH)?

 

[Agile]

The standard wiring uses the 240v output on the orange wire to power the boiler and pump.

So its a little difficult to imagine why your boiler/pump is still operating with the orange disconnected.

BUT a frost stat is often connected to bypass the orange wire.

Is your boiler in a loft/garage?

Can you identify a frost stat? Maybe you turned it up?

Tony

 

[DanM1980]

Hi both,

Thanks for the replies. The new pump was just 3 wires (L,N,E) the first time round it was accidentally connected wrong and when switched on blew the fuse in the isolator switch. Will double check its wired right now, but as its running i guess its ok? Or could this have damaged something? (like the programmer?)


"Is that with the boiler OFF at the programmer (No HW and No CH)?"

Yes that is with the programmer sliders moved to off and the red lights for both CH and HW off. I havent touched any of the wiring for the programmer but have had the programmer off the back plate. All looks ok behind there (no loose wires etc..)

"Is your boiler in a loft/garage?"

"Can you identify a frost stat? Maybe you turned it up?"

Boiler is in the kitchen, not sure what the frost stat looks like? Is this is in the boiler main case (which I havent had off/not really sure I should take off?). The bolier only has the thermostat knob 0-MAX on the front and thats it, so I havent changed anything inside the casing or front cover.

Cheers

Dan

 

[D_Hailsham]

The new pump was just 3 wires (L,N,E) the first time round it was accidentally connected wrong and when switched on blew the fuse in the isolator switch.

What amp fuse was there in the isolator? If it was a 13A, something could have been damaged before the fuse blew. You only need a 3A fuse in the heating circuit isolator.

 

[Agile]

The pump is meant to be connected to the boiler so that the over run is enabled!

Tony

 

[DanM1980]

The fuse in the isolator switch was a 3 amp and was replaced with a 3 amp. I believe the pump is wired in correclty as all I did was replace the 3 wires from the old pump into the new pump. I havent touched any other wiring. Its possible this was part of the intial problem before I changed the pump resulting in us getting no radiators but I am not sure? Ie the fault could have caused the pump (18yr old pump) to be running all the time and killed it off..?

I dont know if it is an interesting discovery or not but I have also found that the boiler and pump will turn off if i turn the cylinder thermostat right down too. The pump seems to turn off for a few seconds when the microswitch is pressed in on the cylinder stat and then starts again?

Is it possible for part of the programmer to fail, but all the lights and clock etc work ok? The battery back up seems good too as it stores the time all day when turned off at the ring main. I have had it to bits and all looks perfect to me inside (although I am no expert) no burnt out looking tracks or capacitors...

Is there any chance this pump is not compatible with my system (i thought a pump is just a pump?). I am watching a few 2nd hand programmers on ebay - may just have a punt on one of those?

Cheers

Dan