System runs on its own?

[foxhole]

Have a pumped system , potterton floor mounted boiler with three port valve and danfoss controller, system has been recently running on with the controller in off position, fires up boiler and pump runs, to stop have to turn of power to system, even after this on restoring power the system sometimes fires up again with all controller settings at off.
Suspected faulty controller so replaced , but no change system stills runs alone without help of controller unit?Any ideas?

 

[ItsOverFlo]

Any ideas?

check clock

 

[jobloggs]

Could it be a wiring fault in your wiring centre?

 

[foxhole]

Has been running fine for past 10 years?

 

[foxhole]

Any ideas?

check clock

Both old and new contoller clocks are fine?

 

[kevplumb]

check the three port valve it may be stuck

 

[foxhole]

check the three port valve it may be stuck

When I power off I can here the actuator back off. Surely the valves mechanical, how does it keep the boiler and pump live?

 

[kevplumb]

microswitch in the actuator

 

[foxhole]

Would a replacement actuator on the valve solve my problem?

 

[kevplumb]

dunno i am not looking at it

take it off and see if it moves when you select heating

 

[foxhole]

dunno i am not looking at it

take it off and see if it moves when you select heating

Are you referring to the actuator ? I can hear it opening and closing during normal use.

 

[jobloggs]

Fox

Remember that two wiring faults may cancel each other out and not become apparent until a third fault appears in a stat or valve. Diagnosis then becomes trial and error. (You already have two working programmers unless by some chance the new one has exactly the same fault as the 10 year old one.)

Get a wiring diagram and check your wiring centre out. You are then in a better position to find the recent fault even if the wiring is OK because you should have a better undestanding of how the controls work.

 

[foxhole]

Fox

Remember that two wiring faults may cancel each other out and not become apparent until a third fault appears in a stat or valve. Diagnosis then becomes trial and error. (You already have two working programmers unless by some chance the new one has exactly the same fault as the 10 year old one.)

Get a wiring diagram and check your wiring centre out. You are then in a better position to find the recent fault even if the wiring is OK because you should have a better undestanding of how the controls work.

Don't see how that will help, if the wiring was correct at installation and working then it's correct now, the fault is intermittent so even If I find all ok on testing it won't eliminate problem.

 

[jobloggs]

What I'm suggesting is that the wiring at installation may not have been correct but may have still worked. The two are not mutually exclusive.

Example: If you reverse the L & N at the back of a power socket then plug in a table lamp the lamp will still light even though the system is not right. However if switch off at the socket, remove the bulb and stick your finger in the bulb holder one of the contacts will be live and if you survive you will know that there was a fault ever though the bulb lit.

Please consider that most people who give advice on this forum have given some thought to the problem and do so in good faith. Suggestions may not be correct but do warrant some consideration.

 

[noonespecial]

Frost thermostat over-riding time switch operation?