cyclinder stat blowing fuse

[Darkwood]

Firstly preparation - understand the system you are looking at, find out what kind of plan it is and download the wiring set-up for this system - then go to check it is wired as it should be, how do you expect to be competent in fault finding in a system you haven't checked that it is initially connected up correctly ..... the system should have been fully tested to operate in all states before you left the last time if you lack the plumbing knowledge to understand the way the system functions you liaise with the plumber till you can understand the sequence of operation when calling for hot water or heating. You can isolate section while powered down and eliminate them as possible faults, whith the plumbers input try manually switching the valve testing as you go ... be careful with insulation tester when electronics are connected like the clock or boiler...... i am in my job forced to test my machine faults without wiring plans or instructions as the equipment is usually 50-70 yrs old without off the shelf part replacement but given the chance if available i always familiarise myself with the schematics and liaise with the operator to identify possible likely areas at fault..... half the time its mechanical issues or operator error and the electrics work fine ...... this is the worst thing trying to find a fault that doesn't exist because the operator has left the gearing in the wrong set-up.

 

[GLENNSPARK]

Eh? What's one of those?

well...you might refer to it as the wiring centre...

 

[RmBo_0]

I'd be in the wiring centre and starting from scratch

 

[Chrisel]

Darkwood,

Basically, due to the two wiring centres, it is a mess. I was hoping to avoid them! I was hoping the more experienced on here would say "there is a common fault with stats caused by ...." thus saving me hours going through the two different wiring centres at different ends of the house figuring out the mess someone else has installed.

 

[Chrisel]

RmB

That is sort of the conclusion I have already come too. To be honest, I don't mind the work, it's just the hassle trying to get money out of people for several hours work re-wiring something "...but it used to work fine". But that's a conversation for another day and another thread....

 

[polo1]

Given that the system has operated for various periods......should/could any combination of parts draw significantly more than 3 amps. Is the pump sticking?

 

[Guitarist]

Considering that the stat is purely a switch (most are even class 2), it's unlikely that this can be the problem. I would definitely be disconnecting the electronics and IR testing the circuits.
Also worth checking that the 3A SFCU isn't also supplying something else

 

[Marvo]

If the plumber wired it up then the plumber should be localising his own faults. If not give him a reasonable hourly rate and reinstall the thing to a standard where it can be easily worked on then go about finding the fault assuming you don't discover it during the reinstall.

 

[ayjay]

trying to sort out a c/heating problem on a website is pure stupidity
the o/p shouldn,t tackle the job if he knows f/all about c/h wiring and shouldn,t charge any money as he,s out of his depth
he should tell the customer that he know sweet f/a, and recommend someone who does

 

[chrish_1977]

It's been quite warm recently so I bet everything has been ok when either the hot water or ch has been on independently, but when both on there is a problem, time to delve into the wiring centres and trace everything through, I had a similar problem, my plumber friend did a load if work to a system and when he finished it isn't work, although it all worked before he started, I traced it to the pump not working correctly, but he would t have it that that was the problem, moral of story always check everything yourself and don't listen to plumbers who play with electrics