Wiring a boiler controller

[Chrisknowlesuk]

I agree coming out of the boiler supply terminals would be dodgey, not a secure fit and a 2.5mm cable essentially only protected by a 45amp breaker.

I'd rather not add a new circuit to the CCU as it is an old MK board and I think I would struggle to find an appropriate breaker?

I've just seen a 45amp dual appliance junction box from TLC. It seems to be designed to accept a 6mm 45amp supply cable and split to two 6mm output cables. One could go to the boiler and one to a 3a SFCU for the control power. That should keep all cables protected and through sufficiently rated connections.

 

[123]

Not quite on topic but I have used the Click Dual Cooker Connection Units and they are great. I am shocked at how much copper is on show from a product image, over sized earth sleeving on the supply, and it doesn't look like any CPC's are doubled over. Everything looks a little strained as well.

 

[Toneyz]

That is rougher than a hedgehogs back! Last one I did I bought the supply cable into a 2way con unit at the heater end with a 63a main switch for the heater and 6a mcb for the control side then they are both isolated by the mcb protecting the circuit at the main consumer unit.

You beat me to it I was going to suggest that idea and if it is next to the boiler you isolate all supplies into it (one isolator) you may still need to fuse down to say 3A from 6A mcb for the controller/programmer.

 

[Chrisknowlesuk]

Update on this job...

Couldn’t find any power to safely tap into. CCU has a last inspection date sticker showing 1998!!!

Looks like an HMO property too judging by the random people appearing. Should have realised all of this on first visit I suppose.

Left job and put in recommendation that they upgrade CCU, add emergency lighting, smoke detectors, CO2, Fire blanket etc etc

Given the job to return and do...

 

[Toneyz]

So what did you decide to do with the boiler controls then?

 

[davesparks]

You beat me to it I was going to suggest that idea and if it is next to the boiler you isolate all supplies into it (one isolator) you may still need to fuse down to say 3A from 6A mcb for the controller/programmer.

Or just fit a 3A mcb if that’s what you need.

 

[Toneyz]

Or just fit a 3A mcb if that’s what you need.

That would be the perfect solution, Dave but not all manufacturers do them and not often stocked by wholesalers.

 

[Chrisknowlesuk]

So what did you decide to do with the boiler controls then?

The original controls were defunct and someone had wired it as simply On/Off via a switch. I left it as I found it and contacted the person managing the property.

Think I may have the job of going back and doing the complete job to bring it all up to spec...

 

[davesparks]

That would be the perfect solution, Dave but not all manufacturers do them and not often stocked by wholesalers.

But in the modern world of next day delivery it’s easy enough to order, unless it’s an emergency job

 

[SparkySy]

What I can't understand with these water heaters is why they don't build in an output for the control circuit, they have a protected output for the pump built in so why not for the control it would save a lot of messing around!

 

[davesparks]

What I can't understand with these water heaters is why they don't build in an output for the control circuit, they have a protected output for the pump built in so why not for the control it would save a lot of messing around!

It’s cheaper for the manufacturer to not put it in.
the higher end units will have it included but in the lower end products these are the kind of corners that get cut to make them cheaper.

 

[Eliza Bennett]

Check your entire system for obviously loose connections, or failed circuits, and examine any fuses which may have popped out on your main board (if you have an older boiler, you may not have a main control board, and will need to check the fuses of all your devices). If you still cannot find a problem, you may need to call in an engineer.