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Thread: Electric UFH

  1. #11
    Automated Home Legend chris_j_hunter's Avatar
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    interesting ... the Aube devices do indeed appear to be sold also under other badges ...

    in our case, the electric UFH will not be the main source of heat for the group of rooms involved - its purpose will be just to make bare feet comfortable & ensure the floor is kept dry ... MVHR will look after humidity, and the heat source in the adjoining main room will ensure general warmth, with the MVHR system taking-away any excess ...

    the calibration I had in-mind was only to define lead-times & on-times - and the thermistor probes we've ordered are B-type, which would presumably fit with the Cortex mapping equation (?) :

    http://en.wikipedia.org/wiki/Thermistor
    Last edited by chris_j_hunter; 17th October 2011 at 10:36 AM.

  2. #12
    Automated Home Legend Karam's Avatar
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    Chris,

    If you can post/e-mail a link to the source or data sheet for the specific thermistor then I can better advise - just I hope you didn't mean a B-type thermocouple.

  3. #13
    Automated Home Legend chris_j_hunter's Avatar
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    thanks, this is what we've ordered ...

    http://www.rapidonline.com/Electroni...th-lead-122892

  4. #14
    Moderator toscal's Avatar
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    Quote Originally Posted by Karam View Post
    I've seen this description of different % on the Aube unit (or maybe some other) and was intrigued by what it might actually mean. By this I mean: to maintain a given floor temperature set point given a particular environment temperature then you will have to feed a particular amount of power into the heating element (which in practice will be delivered by the controller in a pulsed manner - i.e. heating element switched on/off or PWM'd at suitable intervals). So in this context I didn't understand what these different % values mean. Does it effectively mean that the unit sometimes automatically changes the setpoint? For example I set it to 30C but it decides to deliver 25C instead? Any ideas?
    The variable percent thingy is for the mains power supplied to the heating element, (think dimmer for heating). There is normally a click when it comes on then you see the bar go on full and then during the on time the bar gradually decreases. So it must be some sort of PWM method.

    The only thing I would say about Aube is that they used to be a family run company and service was excellent, but now I think Honeywell has taken them over and customer service is almost non-existent. (not my words but from one of my clients who also supplied me my electric UHF)
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
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  5. #15
    Automated Home Guru Nad's Avatar
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    I've had two Aube 132AFs, one in the kitchen and one in the bathroom and they do work very well when left to their own devices. My only regret is not putting in a nice 100mm thick layer of celotex insulation between the floor joists ... a little too late now but will not make the same mistake in the dining room

    My only concern with the Aube device is that they use the 134 to control the other 132s but there is no remote automation for the 134 so I don't really see the point in it. However, if we can get cortex to simulate the signals sent along the pilot wire then that would be a different story. The signal characteristics are in the 134 instruction manual so maybe worth a go.

    On the note of PWM ... this bit of the Aube instruction manual is quite interesting ...

    *****
    Temperature Control

    The TH132 thermostat works differently than conventional electromechanical thermostats. It is equipped with a proportional integral adaptive (PIA) controller which determines heating cycles by analyzing the temperature behavior history within the room. The PIA controller reduces temperature swings providing accurate temperature control while increasing user comfort.
    The controller determines the amount of power required by the heating system to maintain the setpoint temperature.
    *****

    One of my 132s failed sometime last year so I had to get a replacement, but instead of another 132 i picked this up from B&Q ...

    http://www.homelux.co.uk/downloads/L...structions.pdf

    There is a connector wire between pins 3 and 4 which I think could be used for automation purposes. I've not quite got around to testing this theory yet but it's been working fine as a standalone unit.

    This unit also has a bar graph along the bottom so not sure if it uses a similar method of power management as the Aube, I can't imagine Aube being the only company to use this technology.

    I got an energy monitor at home ... may see if I can use that to test out this theory

    Thanks.
    Nad

  6. #16
    Moderator toscal's Avatar
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    Nad did the screen just go blank. There was a batch of controllers the 134 type and the 132 type which had a faulty component on it. Mine was about 2 years old when it failed. Rang my client who supplied the UFH and he said no problem bring it round and I will get my company to send you a new one.
    Hows that for customer service.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
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  7. #17
    Automated Home Guru Nad's Avatar
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    Quote Originally Posted by toscal View Post
    Nad did the screen just go blank. There was a batch of controllers the 134 type and the 132 type which had a faulty component on it. Mine was about 2 years old when it failed. Rang my client who supplied the UFH and he said no problem bring it round and I will get my company to send you a new one.
    Hows that for customer service.
    TBH ... I have no idea any more

  8. #18
    Automated Home Legend Karam's Avatar
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    Quote Originally Posted by chris_j_hunter View Post
    thanks, this is what we've ordered ...

    http://www.rapidonline.com/Electroni...th-lead-122892
    Should be fine, also looks like a pretty accurate sensor (from Rapid's spec. quote)

  9. #19
    Automated Home Legend Karam's Avatar
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    Quote Originally Posted by Nad View Post
    On the note of PWM ... this bit of the Aube instruction manual is quite interesting ...

    *****
    Temperature Control

    The TH132 thermostat works differently than conventional electromechanical thermostats. It is equipped with a proportional integral adaptive (PIA) controller which determines heating cycles by analyzing the temperature behavior history within the room. The PIA controller reduces temperature swings providing accurate temperature control while increasing user comfort.
    The controller determines the amount of power required by the heating system to maintain the setpoint temperature.
    *****

    Nad
    Warning - long winded technical stuff ahead:

    Yes I'm sure it would have to be some sort of PWM if using PI control. But I'm still not clear on the % question (maybe I'll just have to ask them directly). For sure if you are using something like PI then your controller will initially (on seeing a set point hike) typically apply maximum power, then as the temperature gets closer to the set point the power will be decreased until there is an equilibrium between power injected and power dissipated. A practical way to maintain a pseudo continuous arbitrary power level is by PWM i.e switching heater on for varying periods of time within a duty cycle eg. 25% might be on 1 minute ON 3 minutes OFF (duty cycle of 4 minutes). This does not mean that you are then only using 25% energy compared to another day. What it means is that the regulation should in theory be smoother meaning less overshoot and undershoot. This may mean some energy saving in conditions where overshoots would be larger than undershoots relative to a simpler on/off controller.

    The A (Adaptive) bit I imagine refers to the unit estimating the heat loss characteristic on a day to day basis and by also knowing its heatup capability can effectively adjust the position of the setpoint change in time i.e advancing in colder conditions and retarding in warm conditions so that the setpoint is actually reached at the user required time (also you'll get information to tune up the P and I parameters). This bit could save you energy because most people would not be bothered to adjust the setpoint time between summer and winter and probably end up wasting some heat in summer. But you could probably save more significant amounts of energy if the system was also able to change the setpoint itself based on external conditions i.e in summer do you really need the floor to be as warm as in winter (psychology involved too)?

    BTW Cortex can also do PI or PID or even more complex control laws complete with PWM via the advanced controllers option. But have to admit that even though we introduced these as far back as 2002 we haven't seen much used. For wet heating systems although you have to use somewhat more relaxed duty cycles you can get some benefit but until more recently I think PWMing a boiler and the associated mechanics didn't seem to be too popular ... Also the simpler schemes don't work so well when your setpoint is changing regularly. PI in particular can be quite poor hence in industry the addition of D. One downside is that more complicated tends to mean more sensitive to tuning errors i.e if the tuning gets it significantly wrong then the results can be worse than on/off.

  10. #20
    Automated Home Legend chris_j_hunter's Avatar
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    >BTW Cortex can also do PI or PID or even more complex control laws complete with PWM via the advanced controllers option ...

    looking forward to exploring / trying these - we're still installing the plumbing & electrics, but we'll have a mix of electric & wet UFH, and MVHR, and are including sensors (*) while we're at it, to be able to measure things & know what's going-on ...

    (*) pipe temperatures & flow rate, and some float valves, too, in addition to a good distribution of PLHs ...
    Last edited by chris_j_hunter; 18th October 2011 at 06:09 PM.

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