Electric UFH

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • toscal
    Moderator
    • Oct 2005
    • 2061

    #16
    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.
    Renovation Spain Blog

    Comment

    • Nad
      Automated Home Guru
      • Jul 2008
      • 145

      #17
      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

      Comment

      • Karam
        Automated Home Legend
        • Mar 2005
        • 863

        #18
        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)

        Comment

        • Karam
          Automated Home Legend
          • Mar 2005
          • 863

          #19
          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.

          Comment

          • chris_j_hunter
            Automated Home Legend
            • Dec 2007
            • 1713

            #20
            >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; 18 October 2011, 05:09 PM.
            Our self-build - going further with HA...

            Comment

            • RichardC
              Automated Home Jr Member
              • Mar 2009
              • 29

              #21
              Originally posted by Karam View Post
              Should be fine, also looks like a pretty accurate sensor (from Rapid's spec. quote)
              Those are the same ones we use with the QAI modules on my install here. They work fine, I use them to monitor the floor temperature with our wet underfloor heating. (To protect the bamboo floor, they are buried in the last 10mm to monitor surface temp)

              The lead on the rapid ones isn't very long - 60cm so I also use the same sensor from Farnell - http://uk.farnell.com/jsp/search/pro...003&sku=645424 which is 150cm long.

              Did a quick check when I first got these with a small NTC display/controller and they were pretty accurate.

              Cheers

              Richard

              Comment

              • chris_j_hunter
                Automated Home Legend
                • Dec 2007
                • 1713

                #22
                good to know, thanks for that - we'll be using one for the electric UFH, a couple for a water-water heat-exchanger (that has pockets provided for such), and perhaps we'll follow your lead and get some more to use with the wet UFH ...

                we find our QAI are under-utilised - ie: where we need them, there's only one sensor to read (black-bulb, etc), sometimes two ...
                Our self-build - going further with HA...

                Comment

                • RichardC
                  Automated Home Jr Member
                  • Mar 2009
                  • 29

                  #23
                  Originally posted by chris_j_hunter View Post
                  we find our QAI are under-utilised - ie: where we need them, there's only one sensor to read (black-bulb, etc), sometimes two ...
                  Hi Chris, I use a two pair cable with each pair screened to extend the cables from a local junction box just above the skirting to anywhere nearby where I would locate the QAI with another local sensor. A massive pain sometimes to wire, but I'm too tight to leave any channels not used in the QAI

                  As the resistance measured is in the 10kohm area, a ohm or two in cable resistance is negligible.

                  I used Belden 9842 cable to extend my sensors, very expensive but I had a reel left over from a PLC installation job. There are much cheaper variants out there.

                  Cheers
                  Richard

                  Comment

                  Working...
                  X