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How to change boiler's timer ?


I live in a flat therefore uses electricity for both water heating and radiators. I have a conventional Telford Stainless boiler. There is a manual timer on the wall close to the boiler. The timer is set to heat water for about 4 hours in the morning, daily.

Today I got back from work and was trying to store something in the storeroom, where the boiler and the mcb unit are also located. I realised that one of two fuse/switch for water heating in the mcb unit is off. I proceed to turn it on and suddenly the timer for the boiler blow up.

I am now not sure whether the water will be heated.

Please could someone suggest the best procedures to get this fixed?

I will be utterly grateful .

Thank you in advance.


6 Answers from MyBuilder Electricians

Best Answer

You have a short circuit within the system which can only be located using electrical testing equipment by a competent electrician.
It is no use changeing the timer until the fault is repaired.
Get an electrician to test the circuit and give you advice.


Answered 18th Feb 2011

Hi Ray you have have a short on your heating circuit which needs to be investigated.


Answered 18th Feb 2011

Hi Ray - It sounds like you have a problem that can only properly be diagnosed and fixed by getting a registered electician in. The fact that the MCB was in off position suggests it has tripped - possibly because of an overload. When you turned the power back on something had to give - sounds like the control/timer.

When you say this blew up - can you give more detail? A pop - smoke - smell of burning? Did the MCB trip out again?

Definitely recommend you get someone in before trying to power it up again.


Answered 18th Feb 2011

Hi, it would seem that there is some sort of electrical fault on either the timer or even the boiler and this would require an electrician(and one who can deal with heating controls!) There are many who cant do heating wiring lol. Also there should be a 'constant' option on the boiler or the timer which will heat your water hopefully.


Answered 18th Feb 2011

The Water will not be heated without any electric going to the unit. usually when there is an electrical fault within the boiler system the Programmer is always the first thing to blow. this should be investigated by someone who holds Part P qualifications before you attempt to switch the unit back on.


Answered 18th Feb 2011

the appliance needs pat testing and fault finding to check for water ingress or damage. The timer is most like the cause of the fault due the circuitry. Safely isolate, remove and inspect and if competent replace with similar. i reccommend yuo use a qualified electrican undertake this work.


Answered 19th Feb 2011

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