My Final post about central heating.

[Mike Barnard]

Firstly, my thanks to all who have helped, argued, discussed and generally nosed around in my quest for the perfect CH system for my little house. With your help I designed a system, bought the bits and have now installed the wet bits. (Including a weekend without hot water as I ran out of pipe on a Friday night). I was chuffed to bits when I pressurised it for the first time and only had one leak in a copper elbow that was a bugger to get to behind a joist.

BUT. I think I am going to hang myself. As soon as I walk away from the keyboard. Sigh.

My Worcester Bosch boiler cannot be activated by external zone controls. So says the techie's at WB themselves. I've spent hours and hours and a couple of hundred pounds doing the zone thing. I tried to sort the controls today and couldn't figure out how to connect them to the boiler. So I called WB tech support and my boiler (which is only 2 years old FFS!" cannot take it. No way. "Can't I bodge a control in somewhere?" Nope. The text display controls it all. There is no single 'lightitupnow' connection in there.

So after the work I'm stuffed. The zone valves are in manual open mode so the system still works as a normal un zoned system, so all is not lost. But the zone idea is out of the window now.

The controllers and stuff will be going back to the supplier in the morning, no problem there. They're still in their box's unused. The pipe work for the two zones will stay in place as ONE day if this house lasts long enough, it may need a new boiler and the new heating engineer can marvel at the readymade pipe work.

If left unused the two port valves will probably fur up, so I may as well take them out and try to sell them on ebay or in the local rag and get at least a few quid back from them.

Don't you just HATE days like this? Excuse me...

"AAAAAAARRRRRRGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh..... gurgle"

OK, You may all laugh hysterically now. I'll have my coat please. It's that straight jacket over there...........

[TheScullster]

"Mike Barnard" wrote..

Which model boiler do you have? I have a 24Ri condensing non-combi which serves 2 heating zones and 1 hot water zone.

Phil

[Doctor Drivel]

The end switches on the zone valves can be a part of the room stat circuit. All off the boiler is off. The time clock energises the zone valves.

[The Natural Philosopher]

"AAAAAAARRRRRRGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.....

Hold on a second.

There is ALWAYS a way.

Lets have more detail before you despair..

Do you have a wiring diag for the boiler?

[Mike Barnard]

Its a Worcester Bosch. ZWBR 7-30 R 30 HE plus. GC Number 41 311 79

The techie said that many WB combi's COULD zone, but "...sorry, not this one."

[Dave Plowman (News)]

If it can be controlled by an external thermostat it can be controlled by zone valves. That's not to say a ready made interface is available, though.

[The Natural Philosopher]

My thoughts exactly. What is needed is a diagram of how to..

Which I can probably do..

If we know how the boiler expects to be controlled.

[The Natural Philosopher]

Ok..is it this one ?

would appear to have a connection into the text unit thingie for 'TR2' which looks promising. See section 1.8

Yup. TR2 is the 'connection of an external room stat or frost stat' See section 4.3

So that connection can be used to completely override the text display thingie. That's what a frost stat does..

My guess is that an external clock and stat system could be used to completely control the thing with e 'text display being set to 'nothing, ever'

Or use the text display thing for one zone, then set up your motorized zone valves, and external timers and stats and connect the MV switches in parallel between the switched live and switched return on the TR2 connector block.

So that any zone that 'calls' for heat will override the text display.

See? simple innit?

[Mike Barnard]

Scaning stuff now. Will post a link later tonight. Thanks for the inputs.

[The Natural Philosopher]

Don't bother, Found it and posted the links.

I suspect you could also integrate stuff by inserting valve gear between the text display and the unit..

Reading between the lines that's low voltage anyway..so safe enough.

Need to know what you have plumbing/stat wise, then i can concoct a cqt diag for you.

Meanwhile a poke with a voltmeter on pins 3,4 and F on that TR2 conector wouldn't come amiss.

Looking again, at the cqt diag, there is I presume an internal motorized valve to go between CH and hot water yes?

Presumably the text display thing is the 'master stat'

As I see it you have two options. Depending where the master stat /text object is located.

1/. If the text thing is in a really cold place, you can use the extra zone valves to shut down the zones as and when they are hot enough. That is simple enough..just use them as mechanical valves fed via room stats from the boiler switched live, so that when you switch the whole CH off, thats the end of it. 2/. Essentially junk the text display..leave it connected, but wire up a completely different timer and so on from the switched live that feeds the whole shebang, connected to all your room stats, have them fire up the motorized valves, and then connect all those zone valve switches in parallel, between two of the terminals for 'TR2'.

I assume that hot water on a combi is NOT timed - its just 'on demand'?

[Mike Barnard]

For those who have offered to help, (thanks), this is all I have in the way of diagrams. I can scan in better resolution I guess, but obviously the file sizes would increase.

I understand it from the WB techies help the TR2 controller does more than just send a "start now" signal. "It's a clever little box of tricks" sayeth he. I can't see what else it can or should do really, apart from sending a current saying I demand heat.

There are three terminals the box connects to. Marked 3, 4 and F. There is another terminal marked A which is unused in any document I have.

However, I do NOT want to destroy a circuit board by supplying high voltages from the back of a zone valve to a terminal expecting low voltages. Obviously.

Does this make any sense to anyone then?

[Mike Barnard]

But the pdf version is different from my paper one. My paper one just shows a picture similar to 4.2.

I don't see a button to do that either.

Doh... donuts please.

[The Natural Philosopher]

Yup. Ive been looking at the manual some more.

It seems that TR2 allows the temperature of the room to be displayed..

So there is more to it than meets the eye..it also says something about using low resistance low voltage wiring, which suggests that it is an analogue rather than digital link..

Short of breaking into the boiler and accessing the main motorized valve directly, its the best hope we have though.

Unless you simply use the zone valves as sort of mega TRV's (which is still worth it).

Don't worry about the MV's sending mains voltages tho: Sure they need mains to operate the valves, but the switches are just switches. And do not have to be used.

However looking at that bloody boiler, one begins to appreciate how de-skilled it is, and hence how lacking in versatility. Its obviously designed to be used in a small house with one stat and probably TRV's...

Right. I took a final look at the setup instructions on the blasted manual, and my guess is that the so called smart TR2 thing, is, as you say, possibly a smart load of bollocks.

I must say I'd be tempted to break into the cabling that controls the internal motorized valve, and bring the 'open for CH' circuits out to a nice set of sockets meself, and run the MV's all off that..but it probably voids the warranty.

I think you have two choices.

1/. Get a TR2 thingie, and reverse engineer parts of it, or add to it..

2/. simply use the zone valves as flow switches and forget about connecting them to the boiler electrically altogether (for now anyway): Then save up for a decent boiler 'one day' :-) Used with the TR2 room stat, that should at least allow you to control the temps of individual zones well, as long as the rads in the aree where TR2 is sited are balanced right down, so that is the thing that always wants the heat the most.

[Matt]

What crap. WB Tech support are wrong.

What model boiler is it?

[The Natural Philosopher]

Se my last post. They have been more complex than I ever thought possible.

The zone valves are worth keeping tho, but you may not be able to use them to actively *call* for heat. Just to passively REDUCE heat when the main system is asking..

[The Natural Philosopher]

According to what I found, they are sadly correct.

[Mike Barnard]

Thanks NP.

Yep, on the boiler. Why, I dunno, but it does.

Probably.

IF I knew how. I've a lot on my plate at the moment...

Makes sense.

But for all that it's very high in the efficiency, which is one of the reasons I chose it. I was NOT thinking zoning back then. Obviously.

As THEY say. Me, I'm a meccano person. If it fits, I'll fit it. If it needs bending a little, I'll let someone else do it.

Probably? "WB warranty dept? Hi. I need a new boiler gizmo because I took this bit out, wired that bit in and it went pop, sizzle. Is that OK? :)"

Oh, I reverse engineer things like this all day! :(

OY! This is a decent boiler I'll have you know. It shows the temprature on the display an evrithin.

It's late, I need to study for my C&G and I'm pissed off with boilers just now. Thanks for the time you have spent looking at this and I'll think about what to do in the next couple of days. I have no need to rush.

Nighty night.

[Mike Barnard]

I understand what you are saying, but the reason I wanted zones was for cold rooms to be able to call for heat when the main room is already warm.

Oh well. See my other reply.

Night.

[Dave Baker]

The electrickery bits of central heating are absolutely not my thing but I can't see why, with any boiler, you can't have an external controller driving the zone valves and stats which produces a single output to the boiler telling it when to switch on. Even if you had to set the boiler to be on 24/7 with its own controls it would still only fire up when it got a stat signal saying the temperature was low enough. If the external controller sends this signal rather than having the stat itself wired directly to the boiler why wouldn't it work?

Maybe I'm missing something obvious but as I say, I really don't do electrics.

[John Rumm]

Well look at the bright side. it only has three wires. ;-) Of which two are probably power and ground. The third could well be a serial link... got an oscilloscope handy?

(Where is Geoff when you need him? He will probably know what the PCB does with this connection)

Good plan.