non responding potterton profile100e

[runnerman]

My Potterton Profile 100e boiler ignores all Honeywell ST699 controller settings. The system is fully pumped with separate two port valves for HW / CH. The boiler lights when the main power switch is turned on and responds to the boiler thermostat but no longer takes any on/off instruction from the controller. Both actuated valves respond to the controller and the room/HW stats. I have tried replacing the Honeywell ST699 controller with no change in response. Any ideas?

 

[ollski]

If the controls all respond then the clck must be sending them 240v.

 

[baxpoti]

The boiler lights when the main power switch is turned on and responds to the boiler thermostat

Have you got your live and switch-live back to front?

 

[namsag]

More than likely microswitch sticking in one of the valve heads

 

[runnerman]

Thanks for your ideas.
1) The problem was not associated with any recent work on the system so I have not suspected incorrect wiring - It was fine for the previous six years or so.
2) The switched live to boiler remains live irrespective of controller commands whenever the mains isolation switch is on. (As is the unswitched live.)
3) Removing the controller/timer front (including control circuit etc) from housing and connection strip does not appear to have any impact. Boiler turns on irrespective.
4) Both contacts on both valve actuator microswitches remain live irrespective of valve possition. Replaced the CH actuator with no effect on this.
Can you suggest any further checks?

 

[baxpoti]

The switched live to boiler remains live irrespective of controller commands whenever the mains isolation switch is on. (As is the unswitched live.)

Disconnect the switched live.
Is the switched live 'wire' live or is it live at the terminal block, feeding back from the boiler?

 

[runnerman]

The switched live wire is live. The switched live terminal is dead when the wire is disconnected.

 

[ollski]

Sorry read posta little clearer now, as namsag said probably actuator. isolate power and remove both orange wires from the wiring centre, seperate them and see which one is carrying 230v.

 

[namsag]

It gets slightly confusing what is switched live and what is permenant live. The lives to microswitches are the permenant lives (usually orange or grey) and with the valve heads in rest position no current should pass through these switches and then onto boiler (SWITCHED LIVE terminal). This fires the boiler,,, if current is passing through microswitch then its faulty

The live to the valve motor is supplied through the programmer HW/CH switch(brown wire)causing it to open. and the cam to operate the microswitch allowing current to pass through it.

Then there is a seperate permenant live to the boiler permenant live terminal this is to supply power to the pump so it can over run etc

 

[gas4you]

If you have 2 port valves then the grey is permanent to the microswitch and orange feeds the boiler sw live.

 

[namsag]

Dave you will find that most peole out there used either colour as the feed in and out of the microswtch

 

[gas4you]

I only ever fit to the standard Honeywell circuits, but after reading your post again and your reply, I understand what you mean now

 

[runnerman]

Sorted! The problem is the microswitch on the HW valve actuator. I will replace that actuator Monday and we should be ok. Many thanks for all your help and tuition on the basics of control system.

 

[namsag]

If you can get at it sometimes you can free the stuck button on microswitch then give it a little squirt with wd40. Saves buying a new head....