Little Teaser For The Trainees :-)

[Leesparkykent]

Thought id post something that needs a little bit of thought to achieve. Customer has a 12KW electric Boiler which the control side is wired as an S-plan and wants to install a 10.5KW shower in the new en suite they are having built. The main cut out fuse is 80A and customer doesn't want to pay to have this upgraded....... How would you go about making this work?

 

[Karin]

nice one Lee, will have a think bout this later on today

 

[hightower]

Just quickly passing through as got a lot on today, but would it be possible to wire some sort of contactor off the boiler wiring so that the shower is isolated when the boiler is in use, and the shower is made live when the boiler is off.

 

[gazdkw82]

wouldn't you have a cold shower if the boiler was isolated when shower was in use?

 

[hightower]

wouldn't you have a cold shower if the boiler was isolated when shower was in use?

It's a 10.5kW shower so it has it's own heating element.

 

[Bobster]

You could do it that way hightower. Limiting yourself as to when you can take a shower though.

 

[hightower]

You could do it that way hightower. Limiting yourself as to when you can take a shower though.

Or in reverse, so the shower limits the boiler use? Or what about doing away with the shower altogether and just running it off the boiler hot water supply?

 

[gazdkw82]

It's a 10.5kW shower so it has it's own heating element.

ha, im so used to not having an electric shower (iv never had one) that I think all showers rely on the boiler!

 

[Leesparkykent]

Or in reverse, so the shower limits the boiler use? Or what about doing away with the shower altogether and just running it off the boiler hot water supply?

That's my thinking so the shower limits the boiler use as realistically the customer isn't going to be in the shower for that long and wouldn't matter if the boiler wouldn't fire for 15 minutes or so.

So we are going to have a 10mm T&E on a 50A circuit breaker installed clipped direct in to a cupboard directly behind the shower where there is going to be a double pole 50A switch. The electric boiler is in the next cupboard along and all the control wiring is done as an S-plan.

What would be the best way in your opinion to install and connect what we need to achieve this?

 

[hightower]

I'm thinking would it be possible to take a feed from the load side of the switch to the No HW and No CH contacts so that when the shower switch is on the pump gets a signal for no hot water or heating, and therefore the switched live to the boiler doesn't work.

Or am I closer going down the contactor route to handle this like I originally thought? Grasping at straws a little.

 

[Leesparkykent]

I'm thinking would it be possible to take a feed from the load side of the switch to the No HW and No CH contacts so that when the shower switch is on the pump gets a signal for no hot water or heating, and therefore the switched live to the boiler doesn't work.

Or am I closer going down the contactor route to handle this like I originally thought? Grasping at straws a little.

Very close mate. so looking at an s-plan diagram the oranges are the switched live to the boiler. Take a feed from the load side of the 50A DP switch to a fused connection unit, from the fused connection feed the coil of the relay and take the oranges through the normally closed contact of the relay.

 

[Karin]

ooh nice, i like this idea. very cool