Heating on when timer off?

[SyncroMan]

Why dont you turn up your room stat so it call for heating and when it does then remove the timeclock from its backplate heating goes off its the timer

Thanks, i've done that and can confirm that the heating goes off when removed. But going back to Darkwood's comments makes me wonder what caused it, and should it have tripped the mcb? There are no visual signs of damage on the timer circuit board, shouldn't the fuse in the fused connection unit have gone first?

 

[Darkwood]

Time current curves on mcb's can often beat the good old plug/spur fuse in the race to trip and like you mentioned it may have even been within the time clock itself... sometimes without knowing what caused it or seeing the evidence you just have to grit and bare it and replace the timeclock but doing so you need to enlighten the customer that a fault may still exist although its intermittent thus cant be located, then explain the risks of it doing the same again and if so the timeclock wont be replaced under warranty. Sometimes in our job faults occur which are self clearing and leave no trace..... blown capacitors are usually high on the list on the electronics boards as they can short and blown themselves apart clearing the fault and if they are only for smoothing the power supply they wont effect the function of the board but may leave it more prone to transients from the power supply; but thats another fault for another day.

It may be a good idea to check the wiring from timeclock to heater as it may be trapped, nailed damaged etc but only really need to check the 'calling for heat' flex/cable as this is the offending part of the circuit.

 

[mountainman]

In support of Darkwood, I've seen cables running in the same notches as heating pipes.
You may have an intermittent short circuit that has taken a while to appear.

 

[oldtimer]

Thanks, i've done that and can confirm that the heating goes off when removed. But going back to Darkwood's comments makes me wonder what caused it, and should it have tripped the mcb? There are no visual signs of damage on the timer circuit board, shouldn't the fuse in the fused connection unit have gone first?

Listen I dont want to shoot you down here but dont you think you are being a bit excesive ? If your mobile stops working you get another one you dont try to strip it down to understand why and we are talking about a £30-£40 time clock here and I would point out I have replaced many a time clock that was either stuck on heating 24 hours a day or would not switch on the heating either way you have proved it is the time clock at fault just replace it and get on with your life.

 

[Darkwood]

I see your point Oldtimer and yes ive replaced many a time clock myself straight swap walk away, but with regards to OP case he mentioned the circuit tripped mcb and then we've established the timer to have possibly welded contacts, i would question the competence or dedication to his/her job of any electrician who didn't at least try fault find, the thought of returning and charging the customer again after it blows next timer would not only upset the customer but wont do reputation any favours, as long as customer is kept in the loop and fully explained then their wont be any supprises if it goes again and yes sometimes you are left with the only option of replacing without sourcing the initial cause of the fault.
We are trying to help and direct the OP, im supprised with your response, you may hold a opinion of which you have posted but saying 'just replace it and get on with your life' is neither constructive or called for...

 

[oldtimer]

Darkwood i realise there can be sensitive souls on the forum but we are missing a point here we live in an environment where nothing lasts forever ie cars,tv,phones,electric showers, ect plus it is the environment we live in we cannot go down to component level because time wise it is cheaper to replace and timeclocks do fail. I will give you an example 25 years ago i bought a washing machine for £275 and after 5 years the rubber seal went so I replaced it for £60 then 6 months later it was the brushes so I replaced them at £25 and 3 months later the controller went so I bought the same washing machine for £250 (£25 cheaper 6 years later) I then went on a maintenance course where the lecturer explained that everything had a lifespan and that you had to optimise your repair and maintenance he used wahing machine manufacturers as an example explaining that if you got between 5-7 out of a WM then it was good value for money plus dont try to fix it as it was cheaper to replace move forward 25 years and I have just bought my 5th washing machine since then at a cost of £250 so the same cost 25 years ago was worth £750 in todays money. So nothing has changed diagnostics is fine foer finding the fault but a timeclock is the same price it was 25 years ago

 

[Darkwood]

It wasn't your argument or view that i responded to it was your ending comment, just thought it was a little harsh and also was undermining to all advising and helping OP, as regarding you washing machine you are using an example and quoting a lecturer that in their own context i will agree with you, as the failure of the items themselves were the origin of the problem where as in the OP case it holds strong cause for believe that the timeclock may have suffered its demise from an external fault and i would at the very least do an IR test on the cable/flex that signals the boiler to call for heat (while disconnected goes without saying). I think saying just swap it and forget it isn't good advice and not everyone has £20 plus callout charge to spare so its in the OP's best interest and his customers if he can do the necessary once only, im not talking about ripping the house apart or stripping the boiler im just talking about half hour to check for likely causes for the mcb tripping which wouldn't occur from a sticking relay in the timer, it may be the case where nothing can be identified but a open explanation to customer and the issues of it arising again will at least cover the OP back and can also be written in the invoice regarding the tests he's carried out.