The Lemon Fool

I need to re-wire a rather non-standard heating system which has developed an electrical malfunction. I have failed to trace the fault as the massive wiring centre uses the "rats nest" method of connecting up about 150 conductors and three x 4-gang contactors (goodness knows why!) with no accompanying schematic or documentation, and I just can't work out how it (used to) work.

So the customer has elected to have me snip it all out and wire it up again in a logical way and produce a printed schematic of the circuitry for any future technicians wrestling with it.

So my question is, can anybody suggest a program for drawing a heating system wiring schematic please? I need it to have symbols for programmer, room and cylinder thermostats, motorised valves, contactors and pumps. On a Mac please. I've drawn my circuit diagram freehand in Biro on a bit of A4 copier paper, but it doesn't really look all that professional....

Much obliged if anyone can.

I had an answer right up to the point where you asked for Mac software......
My rather complex self-build has everything documented using Microsoft Visio which isn't available on Mac (I'm an electronics specialist and use this software professionally). I have heard good things about SmartDraw on Macs but have no personal experience.

Give https://app.diagrams.net/ a go
It's surprisingly capable, with decent libraries and has been around for years (formerly as draw.io)

-sd

Going off at a tangent, I would suggest looking at the Honeywell Sundial system diagrams and picking an appropriate one.

Building a wiring system around a 10way terminal block strip (even with variations on the original sundial plan), means that any average heating technician can quickly figure out what's what, test and replace failed components using a basic diagram downloaded from the internet, or knowledge off the top of their head.

I've rewired two systems, one S-plan and a rat's nest of a Y-plan with the terminal strip cut into individual blocks.

https://heatingcontrols.honeywellhome.c ... -Diagrams/

The "Wiring Guide" is the holy grail...

servodude wrote:Give https://app.diagrams.net/ a go
It's surprisingly capable, with decent libraries and has been around for years (formerly as draw.io

Yes they have a library in there called Fluid Power (ISO 1219) that appears I think to have the symbols Mike would like.

Chris

pochisoldi wrote:Going off at a tangent, I would suggest looking at the Honeywell Sundial system diagrams and picking an appropriate one.

Building a wiring system around a 10way terminal block strip (even with variations on the original sundial plan), means that any average heating technician can quickly figure out what's what, test and replace failed components using a basic diagram downloaded from the internet, or knowledge off the top of their head.

I've rewired two systems, one S-plan and a rat's nest of a Y-plan with the terminal strip cut into individual blocks.

https://heatingcontrols.honeywellhome.c ... -Diagrams/

The "Wiring Guide" is the holy grail...

This system has a wet central heating boiler running a warm air handler and hot water cylinder, with a separate pump and motorised valve serving each circuit. Thank you, but I'm reasonably confident there won't be a Sundial plan to pick covering this! Besides I tend to wire up my systems from first principles rather than following a diagram. I need to produce a diagram of my wiring design to guide any others following on from me, not so I can wire it up in the first place.

I'll see if I can bung up a photo of the current rat's nest built up around a 24 strip of terminal blocks...

(Pochisoldi exits the stage, having realised that he hadn't checked who the original poster was)