Under floor heating help?

[Tim Howard]

Hi
I'm wondering if anyone can help my try and deduce how something works. I've never come across one of these before and info online is scant, in French, and apparently not free.

Since this photo I've worked out that one of the contactors that had failed. I somehow missed this on my first visit. The customer is happy as they now have functional under floor heating again.

I would like to understand the device on the left which is clicking on and off very regularly during the Option 14 tarrif cheap electricity hours.



Instructions seem to only be in French and not free. The extent of what I can find out is from the Hager catalogue:


"Time proportional regulator which determines with precision the amount of energy required by the installation depending on the external temperature."
"Single slope regulator with limiter, used for heating cables in floor slabs for heat storage during “off peak” hours or for “direct” underfloor heating. Limiting probe incorporated."

Connections in green are used.


As far as I can tell:
There must to be a probe outside and a probe inside. (This system has 3 circuits, so would there be a probe running around the whole bungalow or is it likely just measuring one location?)
The Consigne setting (1) is the desired night temperature.
The Ecarte (2) is the difference between outside and inside temperature.
3 is the minimum time to change state
Limit (4) is the upper limit of the floor slab

I think I get 1,3 and 4. I'm not sure how 2 works and interacts with 1?
Supposing 1 is set to 17 and 2 is set to 5....
Would it activate if the inside temp is less than 17 but only if it's less have 12 outside?

With the radio-teleswitch issue looming, I'm intended to get this board energised 24x7 and add a clock in series between this gadget and and the contactors so it only turns on during the cheap Option 14 times.
Many thanks for any info or advice!

Tim

 

[nicebutdim]

Trying to figure this out, Tim, and managed to log myself out while typing! A lot of this is postulation from limited Hager info on the page you show and I'll happily stand corrected.

'Consigne' is the desired temperature, above which the heating shuts off.

'Ecarte' is temperature differential.

'B.T.' They're calling Time Base. I think you're on the same lines as me - basically duration of heating cycle.

'Lim', as you state, is the floor slab temperature limit.


I think you have pretty much nailed the workings, but I'm guessing 'external' is 'outside' the slab (i.e. the room) as opposed to outdoors.


Edit: While trying to find information about this device I found Google was flooded with links to another UK electrical forum, its Facebook page and other sites associated with that forum, but the links were dead and any relevant thread appeared to have disappeared. Very strange and not very helpful when trying to compare my thinking with thoughts anyone else might have had

 

[kerching]

It looks very similar to the old IMI Pactrol control

 

[Tim Howard]

Thanks a lot. There are about 20 retirement bungalows with this setup all with a looming RTS issue so I wanted to be reasonably sure how it works.
There is one thing still confusing me. If it works as myself and @nicebutdim have both surmised, with consigne at 17 and ecarte on 14 I’m surprised it was coming on at all in the middle of the day yesterday as it’s hard to image a slab/room difference of 14 degrees.

I’m thinking it might work so when the slab temp falls below 14, operate until the room temp reaches 17 using cycles of TB (10 minutes at the moment) ensuring the slab doesn’t exceed 38 degrees.

 

[kerching]

Maybe of no use but…
The IMI pactrol sensed outside temperature and calculated how much charge was needed, say 4 hours fo a storage heater. If the cheap rate was 0001h to 0700 hours it would come on at 0300 for 4 Hours until 0700 and NOT at midnight until 0400. If that makes sense? To be fair though it’s over 35 ears since I fitted one so my memory may be similar to Rachel from Accounts

 

[UNG]

It looks very similar to the old IMI Pactrol control

I was thinking the same, quite a long time since I installed or worked on them though

 

[kerching]

I was thinking the same, quite a long time since I installed or worked on them though

I fitted one for a client. Large site but with storage heaters in one building. They were only staffed Monday to Friday so I also fitted a 7 day sangamo electronic TC ( the one where you need a PhD in Quantum mechanics to program it ) so it omitted Sunday and Saturday charging. It saved thousands of pounds a year, quite staggering

 

[UNG]

I fitted one for a client. Large site but with storage heaters in one building. They were only staffed Monday to Friday so I also fitted a 7 day sangamo electronic TC ( the one where you need a PhD in Quantum mechanics to program it ) so it omitted Sunday and Saturday charging. It saved thousands of pounds a year, quite staggering

I remember doing some calculations on Economy 7 heating and hot water versus gas heating and hot water back in the mid eighties to convince someone gas was the better way forward, it took me around 6 - 8 hours to crunch the numbers and my business partner wasn't convinced by them. He mentioned them to one of the local health authority engineers who oversaw a daywork contract we had at the time, he was quite interested and set 2 university students that were doing their year out in industry to do the calcs with the brief I had used for my calcs after 2 days they came to the same conculsion as me that Economy 7 was not that cost effective and difficult to optimise to suit the prevailing weather
The Pactrol weather watcher did a reasonable job most of the time but couldn't cope with any sudden changes in the weather especially if the temperature dropped during the day and the heaters had not received a full charge, did try shutting down the charge on a weekend on one site but it often caused issues on Monday when the building hadn't recovered the temperature to a comfortable level actually found letting the heaters charge for an hour or two was better while still making a significant saving overall