Electricians got rid of my room thermostat!

[chris]

Hi everyone,

We've just had our house rewired and part of the work was to fit a new programmer and digital thermostat to our central heating system. It's just one of the many major jobs on our list since buying our place last year.

Before the rewiring started, we had a crusty old digital programmer and an old-style rotary room thermostat. The electricians finished the rewiring yesterday but failed to connect up the central heating electrical components properly, so last night we had no heat from our radiators. When I went into the garage to investigate, the boiler was running fine but the pump for the central heating wasn't doing anything.

The electricians came back this morning to sort it out... and their solution was to remove the room thermostat altogether! As I understand it, the boiler and pump will now run continuously when the programmer is set to be on. This just doesn't sound right to me, and certainly sounds expensive! We don't have thermostatic radiator valves at present (although plan to have them fitted on all but the bathroom radiator at some point in the near future).

So here's the first question: does this setup sound wrong to anyone else, or is it just me? Reading around Google Groups, it seems that this might actually contravene 2002 building regs.

The electrician's parting shot was to say we should get a plumber in if we want the room thermostat installed again. Personally, I'd have thought wiring the boiler and pump to the appropriate gubbins would be an electrician's job. Assuming the electrician's a dead loss, who should I call? A plumber? The folks who service our oil boiler? Another electrician?

Final question (if it can be answered briefly!): how exactly should the programmer and room thermostat be wired to the boiler and pump? Before the rewiring started, I could swear that the the room thermostat connected to the pump (and not the boiler) and the programmer to the boiler. I guess that means that the boiler was still trying to heat water when it wasn't needed before the rewiring work started? It just wasn't get pumped around....

It wouldn't surprise me if it was incorrect before the rewiring, as much of the work on the house has been done by cowboys prior to us buying it. We've already found a lot of other things that were done without any attention to building regulations.

If anyone could offer their opinions, it would be an enormous help!

Many thanks,

Chris Wood

[Harry Bloomfield]

[e-mail] pretended :

Certainly not a plumber. An heating engineer, or a competant electrician.

That would depend upon the system. A room 'stat would be essential if TRV's are not fitted. Some systems also include a 'stat when TRV's are fitted.

If you want detailed replies, then it would be best to provide full information - Boiler model? Is there an automatic valve of some sort to switch between HW and CH? Time controller model?

[mike ring]

[e-mail] wrote in news: [e-mail]:

Although it was a long post, it seemed a bit short of specifics!

If you look here:

'll find pointers to a lot of info.

You *do* need a room stat, connected into your programmer.

If it's a programmable digital one (try it, you'll like it), the CH can be left on at the programmer contiuously, the stat will look after the temperature.

You need the radiator in the same room _not_ to have a TRV or the stat will fight the TRV, all other rads can have TRVs.

That's very basic; no doubt if I'm very wrong on any point the corrections will pour in, but I guess you wante to get started HTH

mike

[chris]

Thanks for the quick responses, folks! I realised as soon as I posted the message that I left out the details, but I hadn't expected anyone to get back so quickly!

It's a gravity system with a pump. After posting the message I found the FAQ for plumbing and it described how the thermostat should go in series with the programmer on the way to the pump for CH. The HW should go straight to the boiler.

The new programmer is a Drayton Tempus 7 and we have (had?) a Drayton Digistat 1 thermostat. It's an oil-based system. The programmer is in the hall and the thermostat is in the living room.

The boiler is a Camray Oil Fired Pressure Jet Boiler 51/67. It has a Riello 40 oil pump. The water pump is a Grundfos Selectric UPS 15-50.

I don't know what to look for regarding the valve Harry suggested - as a first time buyer this is the first time I've ever had to think about a central heating setup beyond programming a timer! I can't see anything obvious, at least.

I'll check out the link, Mike - thank you!

[Set Square]

It sounds to me as you have a gravity (convection) HW and pumped CH system. So, for HW, just the boiler needs to run. For CH, the boiler *and* pump need to run. The usual,way of achieving this electrically is a follows:

The HW output from the programmer is connected to the boiler. The CH output from the programmer is connected to the pump via a room thermostat. An internal link in the programmer forces HW on whenever CH is on - even if the manual HW switch is off - to ensure that the boiler runs for the CH.

You definitely need a room stat in circuit - otherwise the boiler and pump will run continuously, and you will fry.

Even when working 'correctly', this system won't meet current building regs because it doesn't have a boiler interlock. It doesn't actually *need* to meet them - because they don't apply retrospectively to old systems. But it's still worthwhile doing a few things to improve efficiency.

The term 'boiler interlock' refers to a method of shutting the system down completely when both HW and CH demands are satisfied - rather than allowing the boiler to cycle on its own thermostat when it's not not needed - thereby wasting energy. In order to achieve this you need thermostats on *both* circuits plus the logic to shut the boiler down. The easiest way to achieve this on a gravity system is to install a motorised valve in the gravity circuit plus a cylinder thermostat on the hot water cylinder, and connect it all up as per C-Plan shown in

alternative - which is even better - is to convert to a fully pumped system - either S-Plan or Y-Plan (also shown in the Honeywell link, above) - but that probably requires extensive plumbing mods whereas the plumbing for C-Plan is minimal.

Which ever way you go, fitting TRVs on all the radiators except the one in the room where the room stat is located will improve efficiency even more.

[Set Square]

I posted my previous response before I saw this - but I guessed correctly that it's a gravity HW system.

There won't be any valves at present - but i suggest that you should seriously consider adding a valve to convert to C-Plan, as per my other post.

[mike ring]

"Set Square" wrote in news: [e-mail]:

*That's* the page I was looking for.

Honeywell can hide information better than anyone I know; even with all the right keywords I couldn't find it.

I'll bookmark it, ....but I always lose the bookmarks!

mike

[chris]

Just a note to say thanks to everyone who replied - especially Set Square!

I feel I know enough now to approach the appropriate people and get the situation sorted once and for all!

All the best,

Chris

[meow2222]

What a joker, I wouldnt get them back. Yes of course you need a room thermostat. TRVs alone, even if you have them, are not a good option, as theyre neither accurate, nor programmable, nor easily controlled.

I hope you havent paid them in full. This is the advantage of paying by cheque, or saying ok send me the bill and I'll pay within 7 days.

If you havent paid, you can get someone competent to sort it all out and deduct all costs from the bill. Personally I'd only pay after they agreed the revised sum as full and final settlement. Its clear youre dealing with cowboys there.

If you have paid, I'd write to them and say unless they pay for to have it fixed within x days, you'll take it up with trading standards. And if they dont, do. Unauthorised removal of the stat from the premises quite likely constitutes theft as well. Trading standards are gonna love them.

NT

[David Hearn]

I thought Trading Standards always said they never got involved with individual cases.

D

[Mark]

Make sure you don't have a Primatic cylinder if you go for this option!

Mark.

[Stephen Dawson]

Should take this up with the Assesing authority as this a notifiable job under Part P. You may have some redress from th scheme operator, if you checked they are registered. If not you may have to bite the bullet, not all sparkies are any good at heating controls, and some are excellent.

Regards

Steve