DIY Wiki - Broken Links!

[Roger Mills]

Thanks, but, for some reason or other, the link still fails when it gets to the Honeywell site.

[Dave Osborne]

Yes, I agree, which is why I've sort of left the internal schematic vague, but give some idea as to what's going on. I have taken the info from this document:-

[John Stumbles]

How do you mean? You shouldn't need to go onto the Honeywell site, unless you follow a link on the web.archive.org saved copy of the Honeywell page which I link to.

[ARWadsworth]

The web archive link works fine here. All those nice drawings are back. The ones that I and Roger wanted.

{

}Nice one John

Cheers

Adam

[Roger Mills]

{

}>> Nice one John

Yes, they're the ones - great - thanks.

[Roger Mills]

It works fine now. Not sure why it didn't when I tried earlier. Probably finger trouble!

Incidentally, I'd not previously come across web.archive.org - it looks like a useful facility!

[John Rumm]

You don't want those.... Dave has drawn a much nicer set:

sticking gif versions up on the wiki now, so we can have them inline in the articles)

[Roger Mills]

Yes, they're pretty good!

I would, however, query the comment which goes with C-Plan about being completely obsolete and unsuitable for either new systems or refurbishments. I agree about new systems, but there are still a lot of gravity HW systems out there which would benefit from being converted to C-Plan - which requires very little plumbing and delivers considerable efficiency improvements relative to the status quo. The only downside compared with a fully pumped system is that when just HW is being heated, the boiler is on for longer than it otherwise would be - albeit cycling on its stat rather than firing continuously.

Does anyone have any evidence that this does not meet Part-L, and would thus presumably be illegal as an upgrade from a 'conventional' gravity HW/pumped CH system?

I'm still not sure about the way in which Y-Plan's mid-position valve is depicted. As everyone knows, it has two microswitches and other components in addition to the motor. I still tend to the view that we should either show *all* internal connections (as for other types of valve) or *none* (as per Honeywell's original Y-Plan diagram).

[Dave Osborne]

I found a website which stated this:

"Recent changes to the Building Regulations have made semi-gravity non-compliant, so fully pumped is the only layout currently suitable for new installations. The Building Regulations now control boiler replacements too, and effectively require conversion of semi-gravity systems to fully-pumped whenever a boiler is replaced."

Clearly, the author of the above doesn't cite his sources and I have to say I didn't check them either. If you think the above statement is bollocks, then please let me know.

Ok, I thought about this. I am of the opinion that showing the full internals of the mid-position valve would not be useful to the vast majority of people and indeed, I couldn't draw it in the space available at any reasonable scale. Also, I do not have such a valve to hand to reverse-engineer the wiring details for. However, it is clear from Honeywell documentation previously cited that the white and grey wires assert the valve and the orange wire is a switched output - which is what I have indicated on the schematic. I am inclined to leave it as it is and I don't see a downside in doing so - it is after all standard practice over a wide range of electrical/electronic industries to show a simplified form of internal operation of a device.

[John Rumm]

I did pause on reading Dave's comment on the schematic, and wonder it it was a little "absolute". While it is true you would not start from there today, I also take your point that it could be an improvement on a unvalved gravity system... (IIRC, prior to modern zone valves and cylinder stats etc, there used to be a type of wax capsule valve you could fit to a cylinder to quench the gravity flow when it was to temperature - can't remember the name of it alas)

Depends on your interpretation I guess. Part L requires fully pumped IIRC, but then again most BCOs will be pragmatic and recognise a non ideal situation that is actually an improvement on what was there.

(having said that I expect the target audience for this sort of info is not going to be the rip and replace to building regs demographic!)

I have no objection to showing all internals - but I am not sure it adds much given context of what the wiring diagram is attempting to show. One could add a note to say that this is a "simplification" that is really there to show the orange wires is switched to provide a call for heat - even if the actual mechanism is not depicted accurately.

Thinking about it, perhaps we could show it empty, but with a note to see another diagram for details, and then maybe Dave would be kind enough to redraw the diagram we have here:

just noticed Geoff's email link is broken in that...)

[John Rumm]

The statement may be ok, but it still leaves scope to improve the controls on an existing boiler when not replacing it (or the cylinder)

See my suggestion on the other response - there is a link to the internal circus diagram as well.

Yup, I think with a note that an "expansion" of the detail is available elsewhere it would be ok.

[Roger Mills]

The statement, as it stands, may well be correct - but it doesn't cover the situation where a zone valve is inserted into an existing gravity system to convert it to a C-Plan *without* changing the boiler. I have occasionally - via this NG - suggested that people should consider this option when they complain either that the HW gets *too* hot or that they have to turn the boiler stat down to prevent this - with the result that the rads are not hot enough. A C-Plan system solves this problem by providing independent control of HW and CH *and* provides a boiler interlock - ensuring that the boiler switches off when both demands are satisfied.

Am I suggesting that they do something which is *illegal*?

Fair enough - it's not a big deal.

I think you've done a great job with the diagrams!

[John Rumm]

I don't think so. Fiddling with plumbing or boiler controls on their own are probably not in the scope of a "controlled activity". Changing the boiler or cylinder is though, and then that drags controls into scope.

[ARWadsworth]

Awesome.

Adam

[ARWadsworth]

I would suggest that installing a new boiler and keeping a C plan in place or installing a new boiler and installing a C Plan would not meet part L.

Installing a C plan in an existing gravity HW system would be good practice according to the regs. Best practice of course being the fully pumped set up.

Adam

[Dave Osborne]

OK, I see you guys are making a distinction between the basic plumbing arrangement and the control arrangement, which I wasn't really doing.

I see now that you could have "C-plan water" with more primitive controls than C-plan and therefore, without changing the boiler or the pipework system, you could improve an existing system by adding additional/better/more flexible controls.

That does kind of make my note on the C-plan water schematic a little too black-and-white. So, I'm thinking of taking it off the drawing. Somebody can explain in the accompanying text on the wiki, OK? Volunteers?

John wants all the individual pictures redone anyway (they currently have transparent backgrounds), so I'm going to have to do a partial reissue either way.

[John Rumm]

You could keep and existing cylinder and boiler, but add a zone valve, a cylinder stat, new programmer etc, making a gravity only system fully C Plan, and that would not involve a controlled activity and would hence be ok.

The phrase "controls" is not limited to just the wiring, but includes the valves (and hence plumbing), stats, programmers etc as well.

Yup, I would go for that...

Such a cruel task master; mush mush!

Re file names - its probably better if you drop the Rev bit from the end since the wiki will track the various versions of the files as they are updated. It also saves having to change the links in the articles with each diagram update (although I will need to do them once to dro the Rev bit ;-)

[Dave Osborne]

Oh tut tut. Y'aint a proper engineer, then...

How about I'll keep the Rev bit - If you want to drop it when you post, that's up to you. ;-) I need to know where I'm up to and what I've issued.

Anyway, they aren't likely to change much are they? Are they?

So, anybody else got any further comments before I reissue at Rev 1.1? :-P

[John Rumm]

Or one who uses RCS ;-)

(to be fair, version numbering docs in the file name is standard practice, but not source files (which are versioned in the header comments) - a picture could be thought of as either depending on context)

Probably not...

Nope, fire away...

[Phil Addison]

Only that it might be an idea to add a rider that the colours etc are specific to that Honeywell valve. I believe other valve manufacturers may differ, as mentioned here