Inspirational wiring centre and 3-way valve.

Some nice engineering going on there. Samwoo is Korean BTW,

Paul Hill

There are some amazing bits of kit in our houses that we just take for granted, and very rarely get an insight into their complexity "under the hood". Another very interesting teardown. Thanks Clive.

Mike Hughes

Thought i would write a brief (edit sorry not as brief as ide thought it world be) overview of UK heating and Hot Water System I have enough knolage to fit and fault find them and my experience is on the tools not from books so minor changes may have been put into place officially speaking but here is a over view of the two main systems (System boiler or Combi Boiler) and the two main ways of setting them up (Open vented or closed pressurised). System Boiler setup A system boiler just heats the water in a loop and sends it to radiators or hot water as required as below Open Vented: Main Boiler with a hot water feed and return (non potable) which is keep separate from the fresh water by means of a header tank in the attic (this also acts as an expansion vessel), this passes through a two single port valves electronic valves (or one 3 port valve) one side feeds the Hot water Cylinder loop (A Pipe that runs through a large storage tank in a loop to transfer the heat from the boiler water into the stored water for the hot taps) The hot water system has its own header tank and never mixes with the radiator water. The other valve or side of the 3 port valve goes through the radiators. Both sides of the valves join back together to return to the boiler. This was the original main source of central heating in the UK for a long time and is the most common example of a Y plan system. All the wiring tends to be linked through a Livestyle wiring box (The messy one) or the newer Honeywell system (the nice tidy one). Closed Pressurised system (With hot water storage) As above if hot water is stored water is being used (but there is an expansion vessel and filling loop added to the system and the header tank is removed) everything else remains the same as above Combi Boiler Open Vented (rare in the UK) This system has a header tank in the attic as above but there is no hot water storage however there is a wet to wet heat exchanger within the boiler where mains water passes on route to the hot taps being heated up on demand the boiler contains its own 3port valve within which diverts the heated boiler water between radiators and wet to wet heat exchanger. Closed Pressurised this system is becoming the most popular in the UK (as using this with a condensing system is the highest energy efficiency) the system works as above pretty much everything is contained within the boiler (expansion vessel, 3 port valve wet to wet heat exchange etc) and the wiring is L N E from a Single Fused Spur, making this system the easiest to install and replace and the most energy efficient and it also allows airing cupboards to be repurposed for storage and no water storage in attics minimising the risk of overhead leaks. There are many other sub systems in use (Low loss headers, microbore systems, heating manifold systems etc) but they all use primary concepts from above and adapt them for the specific needs. As i say i didn’t train as a heating engineer but over the years have worked on many different systems here in the UK including upgrades and installs

There are two main systems in use a closed pressurised loop with expansion vessel and filling loop or an open vented system with header tank filling system that tops itself up if the system looses any water. There are a few other rarer systems but thay are all based on the two above systems in essence. The closed loop is gaining popularity and things like the wiring centres and external 3port valves are becoming less common as these are now commonly contained within the boiler itself now

I agree..... I've seen those valves but not that control board.

I'm far from an expert in HVAC, but I've done a fair amount of my own residential plumbing and heating tinkering, and I've never come across anything like this. I'm in the US, so I assume this is a UK thing. Very interesting!

Circuitmike

What an insightful exploration! Yes that Honeywell stuff is... uniquely engineered. To expand: We see our share of different Honeywell products where I work, and the engineering style stands out as different from a lot of other process control stuff I see happen across my bench. I stop short of saying, "run afoul of", simply because I routinely have to go with my intuition and experience as a QA tech on many of my repair evaluations of their gear, especially the older stuff which the company I work for does see and repair and sell and yet has little information about. Huzzah. :|

Michael Thompson

For US parts I’ve seen aren’t closed loop. However I’ve not investigated historical systems like Chicago and New York City

Cerity

Thanks. Does it mean you use fresh water / tapwater for the radiators? In NL, the heating is a closed loop, separated from the fresh water.

Paul Schuur

https://youtu.be/T7UTDtrmcvM

I used to wire the old type connection boxes, what a bummer in a dark cramped cupboard. I wish these were available then, that's so easy.

I'm quite puzzled how the British heating systems work, also in conjunction with hot tap water. It seems fundamentally different then what I'm used to in NL. I should Google it, but perhaps anyone knows a good source for describing the system?

Paul Schuur

It should be the other way around.

Frank

If the white is hot for call from radiators, and the grey is hot , for no call, for hot water. Then the call for hot water comes and would turn off the grey wire, would the valve stay on radiator only? Or would the higher spring tension of the valve at the end be able to over come the motor and wind it back a bit before the power through the resistors makes it hold? Because it looks like if the call for radiators is continuous that the call for hot water would not work until the radiator call is stopped by the thermostat.

These are called rotary solenoids and use a burnoutable version of a synchronous motor :( A synchronous motor would normally hit the stop and then reverse, these ones hit the stop and stay stalled until they burn out :( Some manufacturers allow you to replace the motor while some charge you an extortionate price for a new top assembly :( It is better to use two Zone valves than a "3 way" !

When the valve is in any position say mid and power is applyed through the dioad and resistor it causes the moter to stall in that position and kinda turn on and off else the spring would keep pulling the moter backwards and then it would cause the boiler to switch on and off constantly so the moter never really shuts down in any position it just stalls in place

This is an AC system, so why the diode? What am I missing?

The top bar in that pic are all live control from stats 3 port valves boiler live links and programmer the top middle is common neutral for all devices and right at the bottom is commen earth the links at the top were moved around depending on 2 port valve 3 port valve or y or a plan system lots of wires lots of bang moments lol

And when you have worked on the original version you learn to appreciate the genius of the pcb version here is what most original lifestyle wiring boxes look like inside (it's the same amount of links and components just without the neat pcb linking everything together https://images.app.goo.gl/hE8PBA1UQuwGpfLT6

Ha, I went through replacing one of these last year. I ended up having to replace the whole thing as motor was burnt out and the valve was seized. I still have the photos of the junction box on my phone so I could rewire it. Oh happy days.

I wish the giant tablesaw at work had something like this, paging through the 100 page service manual for the wiring diagram while inside the saw was a massive pain!

Chewie

Thay are amazing systems I've seen some very interesting ways of wiring y and s plan systems without using a wiring centre over my years of working in rural areas with oil boilers

Building controls equipment, my favorite!

Elliott Krimchansky