Danfoss FP715 fault?

[neil19]

I have a Danfoss FP715 heating controller which has been working fine but suddenly will only allow either the radiators or the hot water to be switched on but not both at the same time.
Any ideas as to the cause of this, is it likely to be the controller itself or the boiler ?
Thanks

 

[doitall]

Faulty cylinder stat.

Need more info.

 

[gas4you]

Have you tried pressing the reset button?

 

[neil19]

Dave - thanks for your post, we have already tried the reset button and it didn't solve the problem.

doitall - thanks, can you give us some more info on the cylinder stat?

 

[DP]

Does the corresponding red light come one when each channel is switched on?

 

[neil19]

If the hot water is on it's corresponding red light is on. If we then try to switch the radiators on the red light, for the radiators, comes on for one second and then it switches itself off. The hot water will stay on.

The same is true the other way round i.e if the radiators are on (red light is on for radiators) and we try and switch the hot water on, the red light, for the hot water, comes on for one second and then it switches itself off. The radiators will stay on.

So in conclusion, both central heating and water work fine but can only be on independantly we cannot put both on at the same time. Any ideas?

 

[DP]

With both channels selected for auto and in OFF state, press one hour button. As you say only one channel will stay active. Does the display show cursor for HW and CH indicating 1 hour selection?

 

[neil19]

Thanks again...

I set it so that both channels are set to AUTO and in OFF state.
I pressed the one hour button for the hot water, the boiler starts and the red light comes on. So far so good. Then I pressed the one hour button for radiators, this results in both lights going off and boiler stops !

I also tried this the other way round...
I set it so that both channels are set to AUTO and in OFF state.
I pressed the one hour button for the radiators, the boiler starts and the red light comes on. So far so good again. Then I pressed the one hour button for hot water, this results in both lights going off...

Any ideas ?

 

[DP]

You do not say if the cursor indicates 1 hour function active when lights go out.

Regardless, suspect power supply problems that causes dropout when two relays operate. Time to get a new timer. New FP715 has improved functions on it

 

[neil19]

Thanks, I'll look into getting a new timer rather doing what I am now which is setting the timer so that only radiators or hot water are activated but not both !

For info, the cursor indicator does also goes off when the lights go off.