Problem with Central Heating since changing programmer

[dbcohen]

I have a problem with my heating system since I changed the programmer. The system is a 28-year old open vented gravity HW system, with a pumped CH system as well.

My Randall 3060 packed up over Christmas - Bug number 1 started moving instead of switching the heating on, until it jammed up against bug number 2.

Anyway, I decided to replace it with a more modern 5/2 digital programmer - a trip to B&Q Warehouse revealed that a Sunvic Select

207XL was a suitable replacement unit for the Randall 3060.

Sunvic fitting guide listed the wired terminals from the Randall's MK3 plate that should be disconnected and reconnected to the Sunivc wallplate - Basically, I ended up with three neutral wires to terminal N, a live wire to terminal L, and a HW and CH on wire to terminals 3 &

1. Dip switches on the programmer were set to Gravity, 5/2 day programming and three time periods.

This left me with some wires left over - a red/black combo that were wired into the same terminal on the Randall, and three earth wires. For each set, I have taped them together with insulating tape and bent them out of the way for now.

However, I can only get the hot water to come on. This warms up two of the three upstairs radiators as well (I think I have an antigraviy valve missing in my system!), but downstairs is very frosty.

Pump is not spinning up, from what I can see. Clearly it is not wired right, but having followed the Sunvic instructions I am unsure what to do next.

Does anyone else have experience with this set up?

[Lurch]

On 30 Dec 2004 17:24:29 -0800, [e-mail] strung together this:

The earth wires won't have anything to do with this. Where did you take the red and black wires from and where do they go? I think this could be the key to the whole thing.

Problem is, there's hundreds of ways it could have been wired, and it could take some amount of testing and disconnecting. If you've got the relatively nsimple programmer swap wrong with instructions in front of you it could get worse from here in.

[dbcohen]

Thanks SJW - I know it is relatively simple - all I can say is that I followed Sunvic's instructions to the letter. I would suggest that they have assumed a more modern system than the one I have?

I am aware that the earth wires are immaterial - I was just trying to be thorough in identifying exactly what has been done.

Examination of the Randall 3060 wiring diagram online reveals wires at terminal 3 on the Randall plate - a live to the pump, and a neutral to the wall thermostat. Presumably this is where my problem is - these wires need connecting in somewhere. My problem is that the Sunvic instructions don't reference the terminal 3 wires at all.

My inclination is to take these, separate them and connect them appropriately to the Live and Neutral terminals on the Sunvic - but I would prefer to take some advice first, in case I do something dangerous or irreparable.

[Christian McArdle]

It is likely the unidentified wire goes to "CH Off" or "HW Off". The earths should be properly terminated into a terminal of some sort, such as a piece of chocolate block. It is unsafe to just twist and tape.

Christian.

[dbcohen]

Christian,

Gotcha on the earths - I was going to do that as soon as I got the heating back on!

Is it safe to experiment with this? I have two wires that were from the Randall Terminal 3, not one - Will I damage anything if I start sticking them into the off terminals?

I have tried calling Sunvic technical help this morning, but I am getting no answer - but I really don't want to go the whole weekend without any heating!

[dbcohen]

Ok, latest update...

Had another think about Christian's advice with the off terminals, and rejected it - the original Randall did not support motorised off valves, so I can't have those in my system (especially as it is so old!)

I have connected one of the Randall Terminal 3 wires to the CH ON output of the Sunvic, and the heating has been restored. Pump is firing up now, and therefore radiators are warming.

However, my thermostat in the living room is still inoperative. I presume that I need to close a circuit with the remaining wire somewhere, but I am unsure what to do. Connect it to the neutral terminal on the Sunvic? I am worried about blowing something up if I do that.

[Christian McArdle]

You may have misunderstood. The purpose of the Off terminals is not necessarily to drive motorised off valves. Many wiring schemes use the off terminals for other purposes. However, I don't think it is the problem in your case anyway.

?intPage=990|intLang=2|strLang=en|intLevel=2|intLevel2ID=990Shows:1 - Neutral

2 - CH On 3 - NC 4 - HW On 5 - NC 6 - L (in) 7 - N (in) 8 - earth

Now see if you can remember where the original wires went and it should be obvious where to place them on the new programmer. If the room thermostat still doesn't work, are you sure it was working before?

Christian.

[dbcohen]

Christian,

Thermostat was most definitely working before.

I have mapped the following to the Sunvic:

1&7 to Sunvic N 6 to Sunvic L 2 to Sunvic CH On 4 to Sunvic HW On

This left the earths (now choc blocked together, Sunvic has no earth terminal) and the two extra wires which I have now determined are BOTH live. These were wired in to 3 on the Randall. One of these is now into the Sunvic CH On, and is giving me heating back, and I don't know what to do with the other. Connecting it to Sunvic N blows the fuse, connecting it to Sunvic L runs the heating even when the programmer is set off.

Thanks,

David.

[Set Square]

Well, you need to make sure that the stat is wired in *series* with the pump - so that the pump runs when the stat's contacts are closed and stops when they open.

In other words, there should be a wire going from CH ON in the programmer to the input side of the room stat. [You may need a neutral too, depending on the type of stat]. Then the output side of the stat should feed the pump.

[dbcohen]

Thanks for that. I assumed as much - the trouble is, I have no idea how to achieve that with what I have! Having the two spare live wires connected together and not on the programmer left me with no heating at all.

As the heating is running for now, I'll porbably just leave well alone until Sunvic's tech departemnt come back from holiday on the 5th Jan, and then take it up with them.

Thanks,

David.

[John]

I'm getting the suspicion that you have lost your way in a "Y-plan" system. Try going to Honeywells site and looking up Y-plan. You then need to determine where each cable from the Sunvic position actually go to before you can proceed to rectify this c*ck-up

[Christian McArdle]

It sounds like they should be wired together, but not connected to the programmer. i.e. treat like the earths. Most likely it is the return from the thermostat and the output to the pump/boiler.

Christian.

[Set Square]

Not so! According to the initial post, it's a gravity HW and pumped CH system - with no zone or 3-port valves in sight!

[dbcohen]

Christian,

That was how I did them originally - unfortunately, in that configuration the central heating pump will not spin up, and I get hot water only.

David.

[Lurch]

On 31 Dec 2004 08:53:52 -0800, [e-mail] strung together this:

You'd be better up getting a local electrician out, Sunvic won't be particularly interested in the fact that there equipment works but yours doesn't. It's a fault in your wiring, not the programmer.

To get it all working you need to find out where all the wires go and what they do, rather than randomly guessing at it.

[dbcohen]

Hold up there, SJW, the reason I'll ring Sunvic is that they provide conversion instructions with their equipment from a Randall 3060, and they did not work.

As I now have a situation where I have identified where the extra wires go (the thermostat), where they were originally connected, and what polarity they are, perhaps they can fill me in.

As for both of your posts, unlike others who have commented you have offered no constructive help at all, just made arrogant comments using belittling words. Why bother responding in a DIY help group if all you can do is that?

Have you never tried to solve a DIY problem yourself by seeking advice, or do you always give up and go and call someone in? Or perhaps you work in a trade and like looking down on everyone else's work? Either way, you have not done a jot in helping me learn the root of this problem - thanks for nothing!

[Lurch]

On 2 Jan 2005 01:58:38 -0800, [e-mail] strung together this:

Erm, they do work, it's just you don't know where the wires go. I've never found a set of instructions that cover every possibility of doing something, they just provide the most common way.

If the red and black are for the thermostsat then the most probable way that they are meant to be connected is the red to CH on and b lack to the pump. You need to find out what *all* the wires do in the programmer, then you can sort it out, everyones's just guessing at the moment.

I said find out what all the wires do and where they go, do that and we'll tell you where they go. (Don't just guess at them, they need testing).

I did try helping, you obviously took offence, I'm not really bothered if your heating works or not, mine works perfectly so you can have a strop if you want.

[dbcohen]

Well, if the instructions aren't that comprehensive, I'd be justified in ringing Sunvic, then, wouldn't I? Contrary to your suggestion...

Yes, thanks for that rehash of the previous suggestions from other posters.

Actually, you never said that. You asked where they went, without suggesting how I found that out. You then suggested I'd screwed up a "simple programmer swap with the instructions in front of me". You also suggested I call in an electrician in a later post.

bothered

And there's that supercilious attitude again. In this context, supercilious means "acting like a clever ass and looking down on those around him" - just to save you looking it up in the dictionary.

Smart comments are really not very nice. Try and be helpful in future, or give your keyboard a rest and don't post.

[John]

Are we absolutely "sure" the OP has got that bit right? Of course it could be a C plan and the HW zone valve is not mentioned

[Set Square]

Well, you can never be *totally* sure of anything in this life , but he did say:

"I have a problem with my heating system since I changed the programmer. The system is a 28-year old open vented gravity HW system, with a pumped CH system as well."

Then further down, he said he had hot water but no heating and that the pump was not running.

So I'm *pretty* certain that is isn't a Y-Plan system.

As you say, it *could* be a C-Plan, which might account for some of the extra unidentified wires. However, with a C-Plan, if the volt-free change-over switch on the zone valve isn't wired correctly, you're likely to get the pump but not the boiler once the HW demand is satisfied - which doesn't quite fit the stated 'facts'.

If the OP's still on board, perhaps he can tell us whether there *are* any motorised valves in the system.