Danfoss TS715 single channel controller

Hi. Had a strange problem with my hot water controller, when it reaches the required time to switch on, you hear an audible 'click', the red light comes on, then immediately it clicks off again. It continues to do this for the whole duration of the 'on' period. If you select Manual ON or +1HR it just clicks on then off immediately. The only way to get hot water is to turn the valve manually, at which point the system kicks in and heats the water up.

I have checked the motorised valve which is fine (swapped it with the CH valve). The hot water tank thermostat also seems fine (I shorted the terminals to make sure the break on heat rise switch was working). Is it likely to be the controller itself? Do these things fail like this? Does it have some form of relay inside which switches the motor valve? A replacement doesn't seem to be too expensive so I was planning to replace it to try...

Any advice?

Many Thanks!

If your saying the red on light on clock goes on and off rapidly .I Have seen several danfoss 715`s do this and new clock is req.

Well the red light only blinks on and off because the unit is trying to swicth the motorized valve on, then something is making the relay click off again. The clock and timer all appear fine... From what I can see anyway.

Is there a relay or transistor inside the controller unit that switches the electrical load for the motorized valve? If so I am wondering if it has simply burnt out, and this is why it clicks off again...

new clock req

would it be too much trouble to wire the "hot water" wire to a temp supply to a table lamp to see if it switches it on, an old guy years ago had used a timer like this to control an outside light, worked perfectly well, and in this case would eliminate all heating controls and should determine whether the clock timer side is faulty or not

Namsag, thanks for the advice. So when you say clock I guess you mean I have to change the whole timer unit?

Kirkgas, I could do that but don't have the time right now. I think I am gonna have to order a timer unit and then if it turns out that there was nothing wrong with the old one, well I guess I'll have an outdoor light switch too! (I need one actually, good idea you gave me!)