time clock fault??

[gaspastemania]

Just been to house with gravity system , back bouler external controls . Owner said other day she awoke to find her heating was on even tho heating was turned off . Yesterday she came home to find heating was on again even tho was off on time clock and couldn't turn it off on the clock only on fused switch.
Its an old danfoss timeclock 14 year old ish , checked basic electrical connections to clock all seemed fine . Thinking its time clock issue and would like second opinion please

 

[rhp]

Is it a Danfoss 103?

http://randall.danfoss.com/PCMPDF/7459v18 web.pdf

 

[diamondgas]

Heating could be working on gravity? Check to make sure the pump has no power supply to it when on hot water only.

 

[gaspastemania]

Its a danfoss fp975 older version of the fp 715 i presume .

 

[rhp]

Hope not too stupid a question, have you tried testing the terminals on the back of the programmer?

http://danfoss-randall.co.uk/PCMPDF/FP975.pdf

 

[gaspastemania]

Tested the electrical connections all fine , when turn on the power to time clock it powers on but seems to do what it feels like doing , e.g shows that heat is on auto with little square block but also has square block next to continuos heat .

 

[rhp]

Sounds knackered then

 

[gaspastemania]

Just wanted to run it by someone else .

 

[rhp]

Let us know how you get on

 

[tamz]

It is the timer.

 

[gaspastemania]

Right new timer on and still having same problem , with the timer showing off on both hot water and heating the heating was still coming on no matter what . owner tells me they have had 2 new pumps in about 8 to 10 years , pump is in very awkward place but managed to get to it and is very hot on touch but not noisy,thinking faulty pump but baffled as to why if it WAS faulty would it overide the time clock??
Any suggestions much appreciated .

 

[diamondgas]

I'd think you need to check out the wiring gaspastemania. what back boiler is it? The Potterton H/Warmer has the facility to wire the pump to the pcb....

 

[gaspastemania]

Its a baxi bermuda , you think its electrical then?
starting to think i should pass this onto a sparks .

 

[diamondgas]

Its a baxi bermuda , you think its electrical then?
starting to think i should pass this onto a sparks .[/QUOTE

The pump sounds like it's getting its power from somewhere .. Gravity h/w pumped heating is pretty basic .. Are sure it isn't heating through gravity? have you checked to see if there's power to the pump when the clock is off or in h/w only? Is the polarity correct?

 

[tamz]

It is definately electrical. On a gravity system the boiler power is supplied from the HW on from the timer and the pump is supplied from the CH on(via the room stat if it has one).
With a std timer backplate HW is 3 and CH is 4.
If a programmer is fitted that is set to give 16 programmes instead of 10 (P instead of G), if the CH is turned on on its own the pump will run but the boiler will not light.
Check your wiring starting with the timer.
Btw sometimes customers are a bit slow in telling you if they have been messing around with things so take nothing for granted

Also as diamond said check for gravity circulation but this will only affect upstairs rads.

 

[gaspastemania]

have not checked the power to pump when switched off at the fused switch, as soon as i turn on fused switch heating goes on and pump spins ,as for polarity correct i wouldn't know as generally never really gone into electrical controls.

How would the gravity flash the heating up randomly?
never come across that before.

 

[tamz]

If it is happening randomly it is nothing to do with gravity circ.

Just a thought.
If the system was previously solid fuel (a lot of bbu's were) there may be a pipe stat hidden somewhere that was never disconnected that is feeding a live back. It is definatly electrical anyway

 

[gaspastemania]

Its a bungalow ,i should have stated that !!!
As far as i'm aware of its always been gas as have done work there off on for years but thats not to say there is a stat hidden somewhere and the electrics in there are not the best . As my electrical knowledge is very limited would you advise passsing this t o a sparks ??

 

[tamz]

It is quite easy to trace these but if you are not sure then it's better to get a spark in.

 

[diamondgas]

Its a bungalow ,i should have stated that !!!
As far as i'm aware of its always been gas as have done work there off on for years but thats not to say there is a stat hidden somewhere and the electrics in there are not the best . As my electrical knowledge is very limited would you advise passsing this t o a sparks ??

I'd agree with tamz ... either have a spark look at it or if you know someone who has experience in fault finding ask them, tag along if you have the time...

 

[stevetheplumber]

tracing this sort of system isnt dificult pastamania power goes to the time clock which then switches it to fire the boiler when hot water calls
when heating is selected power goes to the pump usually via a room stat
you can fault find by working back from the pump when its running despite heating not being selected

 

[gaspastemania]

had a sparks involved today turns out the wiring to the timer was completely wrong and has been for about 15 years or so.sparks was bit baffled why it has worked for so long but all fine now . Cheers for the input guys .

 

[diamondgas]

had a sparks involved today turns out the wiring to the timer was completely wrong and has been for about 15 years or so.sparks was bit baffled why it has worked for so long but all fine now . Cheers for the input guys .

Good to hear you got it sorted ...