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Control of Multiple Panel radiators

ALH_4 Member Posts: 1,790
I would not put radiators with TRV's in series, only in parallel. Did it once and had to re-do it in parallel. Thank goodness for crawlspaces. The relatively low flow rate of a TRV system causes high delta-T's and the second radiator in the loop with have very little output.

<a href="http://www.veha.com/"target="_blank">VEHA</a> makes high quality relatively low priced panel radiators. My favorite hydronic heating system is panel radiators with radiant in the kitchens and bathrooms. Everything can be run at one temperature and in the condensing range with proper sizing of emitters. Consider thermostatic floor heating valves such as the Oventrop Unibox for the small radiant zones.


  • Dave_4
    Dave_4 Member Posts: 1,405
    Mulitple panel Radiator control

    Will use Panel radiators with TRV in a home run configuration to heat the entire house (2200 s.f). Two of the rooms (areas) due to size would benefit from multiple panels.

    One room is 15' x 24', the 24' foot being an exterior wall. I plan on placing two panels on this 24' wall, on either side of the large 8' wide window.

    The other area is a series of rooms (living, dining and kitchen) that due to opening size really are one large area. I plan on putting multiple panels in this area, 2 in living, 1 in dining and 1 in kitchen.

    Question is if I can home run to the first panel and then run in series to the remaining panels and use only 1 TRV on the first panel to control the entire set of panels. it seems do-able, from a piping stand point.

    None of the literature or tech manuals discuss such an arrangement. It just seems that having multiple panels each controled by its own TRV serving one room would be a hassle in that you have to adjust both TRV's for the room.

    We originally were thinking about radiant floor heat using multiple zones. It seems that with TRV'd panels it would be best to go with one zone for the entire house. The panels are the zones. Any thoughts?

  • Ted_9
    Ted_9 Member Posts: 1,718

    Look at the DiaNorn manual. They go through how to figure this out.

  • Bill_17
    Bill_17 Member Posts: 68
    Panel radiators in series

    Most panel radiators can be purchased with what are known as H-Valves, these are the supply/return valves that feed the bottom of most brands of panel radiators, the supply/return connections are 2" (50mm) center-to-center. The temperature control valve is normally built into the top side of each radiator and can accept either a thermostatic control or a 24V actuator which can be controlled by a conventional room thermostats. The H-Valves are available in 1-pipe divering configuration if you want to pipe all radiators in series. H-Valves are also available in 2-pipe configuration where each radiator needs it's own supply and return. If you try to pipe panel radiators in series using only one TRV control, the first radiator will take a high temperature drop and each consecutive radiator will see cooler and cooler supply water. So, parts of the room can actually feel warmer than others due to imbalance. It is best to have a thermostatic control on each radiator, or run multiple radiators off of one electric thermostat and install 24V actuators on all the radiators in the same room.
  • Dave_4
    Dave_4 Member Posts: 1,405

    Was not aware of the thermostat option to control the TRV. Were can I find some more info on them?

  • Bill_17
    Bill_17 Member Posts: 68
    Electric thermostats and actuators for panel radiators

    You should have no problem finding electric actuators for your panel radiators. Once you have selected the radiators, contact the panel radiator supplier for the brand(s) of 24V actuators that match. If you still need help, contact us at [email protected] and we can direct you to someone who offers product fitting most radiator brands.
  • ALH_4
    ALH_4 Member Posts: 1,790

    Why would someone want to run 24V on/off actuators when they could run non-electric TRV's? The piping is the same, but wouldn't the proportional non-electric operators provide better temperature control? Maybe I am misunderstanding.
  • Bill_17
    Bill_17 Member Posts: 68
    24V actuators vs thermostatic operators

    If multiple panel radiators are piped in series (no bypass lines), 24V actuators would provide better comfort than using only one thermostatic (trv) operator for the reasons mentioned above. The best choice would almost always be to pipe the radiators not in series and install thermostatic operators on all panel radiators.
  • ALH_4
    ALH_4 Member Posts: 1,790
    I see

    I did misunderstand. That makes sense. Thanks!
    BILL GARNETT Member Posts: 12
    tekmar 260

    we have a babe ruth system @ our office and use a Tekmar 260 to start the pump and fire the boiler. their is an indoor temperature sensor and an outdoor sensor. at about 68 degrees the boiler and pump turn-on to deliver heat where needed. when i start to feel cold i turn the trv to the next # until i feel comfortable-very simple system that works great ! this was designed by greg gibbs a famous hydro-head in the rocky mtn area.
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