need complicated heating programmer

[Dave Liquorice]

It would never happen with any reliabilty... One thing that is highly unreliable is a human, especially a "non techincal" one being asked to do something "technical".

A "How to..." would help but I bet there are so many variations it becomes unmanageable and thus defeats its own object.

Quite, the base program needs to be set and checked by someone who knows what they are doing, no one else should have access to it. The same goes with room stats, someone will think "oh it's a bit cold" wind the stat up and forget about it.

This would be my prefered option. But I can't think of anything suitable off the shelf. A simple "press for heat button" in each room that turns the heating on for that room/zone for Y period. Subsequent presses of the button have no effect until the heating has been off for X time.

Pretty easy to do with a PLC and a bit of simple programming. The number of required outputs might be tricky(*) but you could use more than one PLC. Some PLCs have interfaces that can talk to modems but I'm not sure if that would provide interactive access or just a means of downloading logs uploading a new program.

(*) 1 output for the boiler and then one more for each zone so your zone per floor zone system should be possible with a single PLC. Requireing 4 outputs (boiler and 3 zone valves) and 6 inputs (3 room stats, 3 push buttons) I think...

Look at the Mitsubishi Alpha or Alpha2 series:

[Christian McArdle]

That was the solution proposed elsewhere in the thread. A fan convector is a fan heater powered from the central heating system. Easy enough to set up zoned with a 1h/2h boost button.

Christian.

[Christian McArdle]

P.S.

[Toby]

Like these:

suggests church halls as an application.

[IMM]

Just buy "single" channel programmers (one for each floor) and have them all in one central location with a room stat in a representative location on each floor. These are readily available and are used on combi's at lot.

[Andrew Mawson]

Tim,

I had the same problem years ago when I installed the heating in my 7 bed three floor Edwardian house - I wanted an 8 zone controller and none were available. My solution was to write a program for a PC that controls 7 zone plus hot water via an interface on the parallel port. It runs 24/7 and since then I've expanded it to be my internet / adsl portal, and also monitor my water and electrirty consumption. I've also added X-10 controls which among other things brews me a cup of tea in the morning at varying times dependant on the day of the week.

Andrew Mawson

[Owain]

"Dave Liquorice" wrote | > It might be better to have an easy override system and ensure | > that the system can heat up a room quickly. | This would be my prefered option. But I can't think of anything | suitable off the shelf. A simple "press for heat button" in each room | that turns the heating on for that room/zone for Y period.

That's a standard extractor fan / staircase lights timer.

| Subsequent presses of the button have no effect until the heating | has been off for X time.

I don't think they do that, but two time-delay electronic relays interlinked would.

An alternative would be PIR occupancy detectors in the rooms used to bring up the heating when required. If the building is kept on a set-back temperature during the 'core occupied' hours the room should heat up fairly quickly; especially if someone routinely turns up 15-20 minutes before to arrange chairs etc or if fan-assisted convectors are used.

Owain

[geoff]

In message , Tim Mitchell writes

The cheapest solution would be to fit TRVs on each radiator

Otherwise, you could ask lucifer very nicely to heat rooms on demand

[Ed Sirett]

A £30 programmable themostat is installed on each floor. These can do 6 different temperatures with different programmes on every day (if needed). The thermostats govern the Zone valves which in turn fire the boiler. [Extended S-plan see main FAQ].

Wireless versions are available and it is a straight cost of wiring v. the extra £40 quid (say) for the wireless version.

[Dave Liquorice]

In the short term but you'd never get people to turn 'em up/down as required. They'd end up just like all other TRVs in "public" places, flat out.

[Dave Liquorice]

Starts getting complicated. A PLC is all firmware and thus very easy to change in response to altered use of the building.

That I do like, takes the human out of the loop completely as far as when heat is supplied. My timed system wouldn't work effciently for lots of meetings shorter than the average set in the PLC.

If only to stop complaints of "the rooms are always to cold" from the life painters and "the rooms are always to hot" from the belly dancers. I think there still needs to be a user tweakable, limited range, temperature control of some sort. Not sure it actually has to do anything other than turn a local indicator lamp on...

[IMM]

With this method you need an overrun timer, otherwise the zone will be on and off as the PIR sees movement or not in the room.

Do not have local user temperature adjustment if possible. The good point about using a central bank of CM67 stat programmers is that remote temperature sensors can be fitted and the temperature control is away for the in-fighting.

[IMM]

TVR heads only last about 5-8 years anyway. A good quality electric/electronic system will last 18-20 years, making it cheaper and less hassle in the long term.

[IMM]

How are you controlling temperature in the church?

[Andrew Gabriel]

I've done something similar with 2 zones, but it would easily expand. For temperature setting, I use Satchwell DRT3451's (chucked out from work) which look like a regular thermostat but are actually just a

3k potentiometer. They also include a thermister for remote sensing, but I'm not using that. (If you buy some, there's a variant without the thermister -- a web search will find the specs.) Instead of the thermisters, I'm using Dallas temperature DS1820's (IIRC) which look like a transistor, but are actually microcontrollers with an accurate temperature sensing element. You can run lots of them off a single twisted pair which they use for both power and digital signalling, with each having a unique address so you can identify them, so a single twisted pair snaking around the house can monitor the room temperatures, loft, garage, outdoors, fridge, freezer, etc.

The pseudo thermostats and the DS1820's interface to a PC which does the maths to see which zones have a heat demand and operates the boiler and zone valves. There is a concept of several temperature settings, only one of which (in each zone) is governed by the pseudo roomstats. Other settings such as night time and frost protection are held in a configuration file. Also, the min and max roomstat setting is configured -- the Satchwell DRT3451's can be set up to

35C which I would never want the room to be set to.

The PC interfaces to a Comfort alarm system, and this allows me to call up and switch the heating on on my way home. In principle, it would be quite easy to allow setting via the web too, but I only allow network access to home via VPN from work, so I can monitor it at work and also switch heating on just as I leave via the network.

I did a earlier installation in a different house which again used Comfort enabling remote control, but didn't use a separate PC and didn't have all the features. The PC is also useful for logging what's happening, so you can look back over things like rate of temperature rise in a given room, and decide it would benefit from an additional radiator. Also, it can signal alarm conditions back to Comfort such as if temp drops lower than expected with risk of pipe freezing, if boiler locks out, if freezer gets too warm, etc, and Comfort can raise an appropriate alarm condition.

Unfortunately, this system is a long way from being productised; I didn't ever implement it with that in mind.

[Christian McArdle]

Twin channels are usually about 2 quid more than the single channel, so would be much cheaper (and take less space) if there are lots of zones.

Christian.

[Tim Mitchell]

In article , Andrew Gabriel writes

That's interesting, I am an electronic engineer in real life and could design such a bespoke system (and I have considered it), but I am wary of installing such a thing at the church because of the support issues. If I get run over by a bus, or move away from the area, or whatever, who's going to fix it if it goes wrong, as it inevitably will eventually?

The advantage of doing this is that you can customise the user interface at will with nice easy to understand buttons.

[IMM]

A two channel is confusing. It has DHW and CH. A single channel is just that, one single channel that is simple to use and understand. All you need do is label each programmer to indicate which zone it controls. They are cheap enough and the simplest and cheapest method.

[Neil Jones]

My sister has got a zoned controller in her flat - she can program up to

10 zones with multiple on/off periods and allocate each heating device to a specific zone. It's in conjunction with electric storage heaters and fan assisted heaters, which may not be applicable to you, but it might be possible to use the output to drive a zone valve or similar.

I'll try to get the details from her if you're interested.

Regards

Neil

PS my other sister has a simpler version, Credanet, in her flat, but it's only 3 zones.

[IMM]

This single channel programmers is very simple to operate as it is analogue. So no confusion by the pensioners and old caretaker. No digital LCD displays. And it is cheap enough. .....

HORSTMANN 425 Coronet, single channel time switch. 4 programmes offer ON/OFF twice a day, ON all day, or permanently ON or OFF. Suitable for combi-boiler, warm air systems or extra zone control with advance switch.

DIMENSIONS : 152 x 107 x 39 mm. Mounting : wall fixing plate to standard 9 pin.

BES Part No.13505425

£24.48 plus VAT