Just been looking at the CH Controls and Zoning section - which discusses the various heating 'plans'. For each plan - Y-Plan, C-Plan, S-Plan, W-Plan etc., there is a link to a description on the Honeywell site.
. . . except that Honeywell have taken down that very interesting reference document, and you you now get re-directed their home page - which isn't very useful!
Anyone know of an alternative source of these plan descriptions, which could be linked to, instead of the 'dead' ones?
I came across this last week, and was going to post a similar request until I had a closer look at the redirect page that Honeywell are serving to bounce the dead references back to the home page.
It sez ... "Please wait! You are currently being diverted to our new website at
However, if you place your cursor over the link (as if you would if the redirect failed), you will notice it really links to a spammers revenue raising parking page.
I've spoken to someone at honeywell about this - seems they have yet to fix it (or my report of the issue went over their heads).
:-(
Salus do good clear diagrams
PS Roger you remember the Y Plan timer overrun problem you helped me with a few weks ago? I had to set the overrun timer to 7 minutes in the end. WB technical informed me that the 24Ri overrun is just a 3 minute timer overrun. I may have more questions about that install if you are still prepared to help.
the same as the original Honeywell ones. Interestingly the combined one which you cite uses 16-way wiring centres, whereas the individual ones use
10-way boxes, more like Honeywell.However, neither covers C-Plan or W-Plan.
I'll do my best! What led you to the 7 minute setting - what actually happened if you set it to less?
The original Honeywell pictures are available
S plan
I cannot find it.
I have driven over 800 miles today and so I am a bit knackered.
But my quick reply is , when the pump stopped it seems that the water in the system was so hot it tried to go up the expansion pipe to the tank in the loft. Lots of banging noises and the vent pipe got very hot. If I kicked the pump back on then the vent pipe went cold and the banging stopped.
I still suspect a plumbing problem somewhere. I can take pictures of the plumbing if it helps.
Yes, those are the ones - well, the wiring diagrams anyway. The original document also had a plumbing schematic for each plan.
I'm not sure how common W-Plan systems are these days. They use a simple diverter valve rather than a mid-position valve, and can thus do HW *or* CH but not both at the same time - usually with HW priority, so you get no CH until the HW demand is satisfied. AIUI, W-plan was invented *before* Y-Plan, and the mid-position valve used by Y-Plan was subsequently invented to overcome the problem of having to wait for the DHW to get hot before having any space heating. However, with modern fast-recovery cylinders, that is less of a problem - and I've heard it suggested that W-Plan systems are coming back. They're certainly simpler from a wiring point of view, and have less failure modes than Y-Plan.
Pictures would probably help - plus a diagram showing the overall pipe layout.
On the face of it, it sounds as if there isn't a clear unrestricted path from the boiler to the vent pipe but, if so, it's curious that this is fixed by running the pump - unless that simply causes the residual heat to be dissipated somewhere else, which I suppose is possible.
If my system over-runs for an insufficient period, the boiler's over-heat stat trips - but there's no drama such as banging and gurgling etc.
Good point.
I am sure that I have seen variations of the W plan for gravity HW using a 2 port valve!
I doubt W plans will make a comeback. A W plan cannot meet part L of the building regs as it does not allow total independant control of the HW and CH circuits.
I will ping you when I get some photos. The customer has not complained for two weeks now so it seems to be working.
Adam
I think you're confusing it with C-Plan, which does that.
W-Plan is fully pumped with a diverter valve, and *does* provide independent control and a boiler interlock, so I don't see why it wouldn't meet Part L.
If you actually mean C-Plan, that also provides independent control and boiler interlock. It's actually devilish cunning in the way that it uses the auxiliary change-over contacts in the single 2-port valve.
It was half and half. It was definately neither. I was ripping it out for a plumber who was installing a combi.
The reason I suggested that a W plan would not meet Part L is because you have to heat the hot water up regardless of need on a W plan and Best practice for boiler controls says that the HW and CH should be provided with independant time controls.
Cheers
Adam
I don't think you're right. Unless I'm mistaken, if you turn HW off at the programmer, the HW demand will be deemed to be satisfied, and it will go straight to CH. Even if that is not the case, you could achieve the same thing by turning the cylinder stat right down.
The Honeywell W plan download from here
You are correct in that you can turn the cylinder stat down. That would be a PITA or impossible for most people (do you know many jobs I do where the customer does not know where the fuse box/CU is?)
About 4 years ago (Christmas time see PS) I believe that you made a post about W plans and using the HW off from the programmer to allow CH only. I cannot find the post on Google. I remember not trying it in the end (although I agreed with your idea at the time) as I worked out that the boiler would fire up constantly.
I also found this for Y plans (the wiring diagram is actually incorrect, see if you can spot it?)
To be honest, W plans are so rare that most people do not know about them, but it would be good to still have a Wiki article that covers them to give help when needed.
Cheers
Adam
PS Christmas time for sure as I was wearing a Santa outfit at the house I mentioned in my reply to you.
Yes, you're right - I stand corrected! With the system as specified, the valve *only* gets energised, and the flow diverted to the CH, once the HW stat is satisfied - so you *have* to have the HW on unless you turn the stat down.
[I was sure that I previously registered, but it didn't think so, so I've (re-)registered and can now see the documents.]Interesting that you should say that. I have no recollection of suggesting that in the past (but that's no guarantee that I didn't!) BUT I was about to suggest just that before reading your paragraph above - and still am!
I reckon that if you connect the programmer's HW-OFF to terminal (5) in the junction box, that would have the desired effect. The valve would be energised all the time but the boiler would only fire when either the CH demand was unsatisfied, or the HW demand was *satisfied*. The latter is unlikely, since the water is not being heated - but I suppose it *could* cause a problem if you turned the HW off when you already had a tank of hot water. It would work best if HW were either permanently ON or permanently OFF at the programmer.
timer (even though it's there on the control schematic)? Incidentally, that particular diagram is *not* the same as the one you can download from
Probable - although the downloadable 'traditional'ones are even better for imparting a basic understanding - but maybe that's because those are the ones I was brought up on? If they are going to be referenced from the Wiki, they'd have to be put somewhere where you can see them without needing to register - which would very likely violate Honeywell's copyright and terms of use - which I blithely ticked to accept without reading!
Agreed.
Funny what you remember. My wife says I always work out when things happened by remembering what car I was driving at the time! [Ah yes, we went there in the blue Rover 600, so it must have been about 1995 - or whatever].
We could host a copy of the faq site and link them... see if anyone notices.
Last house had one when I moved in... was replaced with a mid position valve shortly after ;-)
Most SWMBOs it seems keep a catalogue of all your DIY mistakes. Ready to recall when the moment suites!
One small problem. Terminal 5 in wiring centre is linked to term 2 of the cylinder stat. A HW off with the stat not calling for heat will fire the boiler.
Correct. That was quick.
I will keep looking for others then.
Adam
Yes, I did acknowledge that in the para above yours, but I didn't see it as too much of problem if you used the system in a certain way. But, on reflection, it probably *would* cause problems for the uninitiated - which is presumably why Honeywell don't do it like that.
I think we're veering towards violent agreement! It's good to be able to float ideas and to have them politely scrutinised. I wish that more of the threads in this NG were like this one!
Excluded from politeness are the threads that involve anything to do with CFLs, laminate, Combi boilers, decking, solar power, wind power, spot lights or plastic pipe cutting techniques. Did I miss any out?
Adam
OK, I've redrawn these plans in Autocad. If someone wants to put them up on the Wiki they're welcome. Please let me know what format/size you want them and where to send them.
Here's a sample: -
For something like that, I would guess a gif or jpg at 1024 wide would be handy for use in the wiki, or a PDF could be called up from the FAQ.
You can upload the former directly using this page:
Thanks for the heads-up Roger. Try:
s {
unless you're going to show *all* the gory details - Honeywell just show the wires disappearing into the case. Having said that, they *do* show the internal motor and auxilliary contacts on the 2-port valves used in S-Plan systems.
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