Honeywell ST699 tripping RCD when sliding CH switch

[DaveD1977]

Of course but unfortunately, invariably there is little logic to where some of these items are placed. Space will be a defining factor, as it's open vent then the placement of the feed and vent may also have defined things.

Yes, of course following the pipework will also lead to the pump eventually.

You say the pipes exit left but the flow and return on a Bermuda exit/enter the right hand side of the boiler. Those pipes where the programmer is may be the mains flow and return and as they are on the right hand side and where the cable runs, that would probably be the place I'd start.

Super helpful, thank you very much for explaining.

 

[DaveD1977]

It's a rubbish photo as I've had to poke a camera on a stick through a hole in the floor, but could this be the pump? It's next to the flow/return pipes and seems to be where the power cable goes to...

 

[Exedon]

Yes that's the pump smc commodore by the look of it .
It's ancient change it!

 

[Madrab]

+1 ... that's the bugger

 

[DaveD1977]

Do you think I'll have to pull up enough vinyl planks to expose what I imagine will be a full board of plywood (that covers the floorboards) or do you think the heating engineer could cut a section out of the plywood and then cut a couple of boards to get to it?

 

[Madrab]

If it was me then I'd be using a multitool to cut out just what would be needed to get to the pump and valves, usually to the nearest joist. Guess that would be a question for your engineer tho.

 

[DaveD1977]

If it was me then I'd be using a multitool to cut out just what would be needed to get to the pump and valves, usually to the nearest joist. Guess that would be a question for your engineer tho.

Thanks, I was hoping that could be an option. I'm going to call him tomorrow and fingers crossed he's as pragmatic as you...

 

[Madrab]

Thanks, I was hoping that could be an option. I'm going to call him tomorrow and fingers crossed he's as pragmatic as you...

The biggest trouble will be if the pump valves don't shut down, then there could be a whole other set of problems but that's a 'cross that bridge ....'