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Constant Circulation

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Constant circ is really creating a "steady state" a place were you are maintaining and never forcing. Just alittle heat here and alittle heat there and never very far from the home(TRV setting).

How about this Tekmar uses this too by the way. We all have cars so we can relate. When you are stopping and starting in city traffic you are not only getting worse fuel economy but you are also putting more were and tear on your car-THis is an on/off type of heating system.
Now a constant circ system is like crusing along on the open road with the top down on a sunny day. No stress just crusing along life is good!

Worried about the measly little circ pump at 75 watts per hour. That .08 cents a day and 240 days of heating thats $38.30 for the entire heating season. I think it is a worthy investment.

Not to mentions I have the most satisfied customers of my career since I have been installing a continuous circ systems.

Oh yea I won't even mention the comfort becasue you can't beat it.

Jeffrey

Comments

  • Frank_35
    Frank_35 Member Posts: 2
    Constant Circulation Controls

    I'd like to improve the efficiency of my home's two-pipe hot water system heating system by adding constant circulation and outdoor reset. I think a Tekmar 260 boiler control would fit the bill and also allow for indoor feedback to the water temp algorithm. Does this (or any similar control setup) allow for running the circulator constantly, or would I need to wire the circulator up with a manual switch to accomplish this?
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Even if it does specifically allow controller direction

    I would wire the circulator up to a switch or an outdoor temperature controller. That is how I run mine, via a Ranco controller. Circulator runs when it is 65 degrees or cooler outside.

    I did this with a Vitodens too, saved integrating with the controls and it was no big deal either way.
  • jp_2
    jp_2 Member Posts: 1,935
    brad?

    do you really need heat at 64F? seems awful warm? i tend to start around 50-55F, unless cloudy damp and raining.
  • ALH_4
    ALH_4 Member Posts: 1,790
    WWSD

    The Vitodens turns on the circulator any time the outdoor temperature is below the target indoor temperature. Not much heat being added, but the system wakes up and flow begins at that point.
  • Simply Rad_2
    Simply Rad_2 Member Posts: 171
    Frank

    What are you using to distribute the heat off the two pipe system. What type of heat source are you using also. Outdoor reset is very simple yet elligant way to help with achieve the constant circ concept. Most off all

    Jeffrey
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Not so much

    that I need heat at that point (each house has a different balance point) so 65F is conservative, I admit. I suppose it could be set lower and I would be just fine so you raise a very good point.

    It is rather "set it and forget it".

    There are those spring or fall mornings where the outside may warm up a bit after a cool night when the indoors just needs the edge taken off too. Small price to pay for a practically nonexistent problem. The temperature does stay even though.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    I did figure out a way to get WWSD with the Vitodens--even if it is kind of perverse...

    Used a simple setpoint controller (remote sensing for outdoors of course) with NO and NC contacts.

    Connected it to X 4.1 and X 4.2 terminals via the NC connections on the setpoint controller.

    Set address 011 to 001 to enable the external call or external switching function.

    Verified address 027 set to default (000) for "external switching of heating program". The other option (001) is for "external call for heat". Vitodens can do one or the other, NOT both simultaneously.

    Set address 0C8 to 000. This means that when the contacts are open that both DHW and space heating are ON AND FOLLOWING THE TIMER PROGRAM. When the contact is closed, DHW and space heating are still on, BUT INDEPENDENT OF THE TIMER PROGRAM.

    Finally, set the moon dial for my WWSD temp--currently 55F.

    Then set the timer for constant operation at "reduced mode", in Vitodens speak where you tell the boiler when to operate at "normal" mode (NOT reduced mode), this means setting the timer program for nothing. This makes "reduced mode" constant.

    SO, when the outside temp is BELOW WWSD point the contacts are closed and the boiler runs independent of the timer (thus in normal mode). "Tel Program" appears in the display to let you know things are working properly.

    When the outside temp rises above WWSD point, the contacts open and the boiler follows the timer program--again set such that "reduced mode" is constant. Since the moon dial is set at the same point as WWSD, the boiler calculates "0" for a target, does not fire and the circulator stops.

    Rather odd, but it works perfectly. You do however loose "normal" use of the timer program.

    Viessmann is supposedly considering a change I suggested that would make this MUCH easier and retain the use of the timer.

    Address 038 is for setting the "minimum supply temperature in heating mode". Default is 20C (68F).

    If you set it higher than the target computed by the boiler it fires to the value in address 038. (I presume this is really only useful when you want to establish an absolute minimum based on your emitter(s)).

    What I asked for however is the opposite: instead of always firing to the minimum setting even when the target lower, it would be VERY handy if it did not fire until the calculated target was above the minimum temp setting. In effect you would get a "dead band" in the heating curve. To set you only need calculate the target temp (using the current curve) at your WWSD point and set this temp as the minimum allowed.

    Other parameters have settings that affect their mode of operation. Why not this one as well?

  • Frank_35
    Frank_35 Member Posts: 2
    it's a '30's house

    with cast iron rads - approximately 80 MBH EDR. Packaged Columbia boiler recommended (oversized, of course) and installed by oil distributor ca. 2002 works ok, but with recent colder temps I've noticed that the boiler water temp rises about 20 degrees after the burner / circulator shut-down. I'm sure I'd be better served transferring this heat into the house rather than losing it up the flue pipe.
  • Simply Rad_2
    Simply Rad_2 Member Posts: 171
    Frank

    Instead of just a tekmar control have you thought about a boiler replacement. One thing though you would have to go to gas to gain the benefits of the modern moduating/condensing boiler. They are the cats meow in the heating world. They have the reset controls built in and they match your load depending on what is needed at that time of use(moduating gas valves). Your unit works but the performance is lacking. You can do so much more reset when it comes to a condesning boiler rather than a cast iron which you must protect against cold returns.

    You will gain the "Ultimate in Comfort and Efficiency"
    Jeffrey
  • scott markle
    scott markle Member Posts: 17
    tekmar 270

    Frank, the 270 is a nice controller. just installed one on with a buderus gb142. This unit will operate the system in constant circulation mode provided the heat demand contact is energized. In my installation I wired this contact to a switch to allow the user to turn heat off in summer. There is a wwsd setting on the control but if its set to 68 or so there will be unwanted heating in summer months if heating demand contact is still energized. Use of the optional indoor sensor is probably a good idea. One drawback, adjustment of desired indoor temp. is in the adjustment menu structure of the control by several button pushes, and the control it self will probably not be convenient to the living areas. The unit can be equipped with a remote timer which will allow for a occupied/unoccupied modes.
  • scott markle
    scott markle Member Posts: 17
    tekmar 270

    Frank, the 270 is a nice controller. just installed one on with a buderus gb142. This unit will operate the system in constant circulation mode provided the heat demand contact is energized. In my installation I wired this contact to a switch to allow the user to turn heat off in summer. There is a wwsd setting on the control but if its set to 68 or so there will be unwanted heating in summer months if heating demand contact is still energized. Use of the optional indoor sensor is probably a good idea. One drawback, adjustment of desired indoor temp. is in the adjustment menu structure of the control by several button pushes, and the control it self will probably not be convenient to the living areas. The unit can be equipped with a remote timer which will allow for a occupied/unoccupied modes.
  • scott markle
    scott markle Member Posts: 17
    tekmar 270

    Frank, the 270 is a nice controller. just installed one on with a buderus gb142. This unit will operate the system in constant circulation mode provided the heat demand contact is energized. In my installation I wired this contact to a switch to allow the user to turn heat off in summer. There is a wwsd setting on the control but if its set to 68 or so there will be unwanted heating in summer months if heating demand contact is still energized. Use of the optional indoor sensor is probably a good idea. One drawback, adjustment of desired indoor temp. is in the adjustment menu structure of the control by several button pushes, and the control it self will probably not be convenient to the living areas. The unit can be equipped with a remote timer which will allow for a occupied/unoccupied modes.
  • scott markle
    scott markle Member Posts: 17
    tekmar 270

    Frank, the 270 is a nice controller. just installed one on with a buderus gb142. This unit will operate the system in constant circulation mode provided the heat demand contact is energized. In my installation I wired this contact to a switch to allow the user to turn heat off in summer. There is a wwsd setting on the control but if its set to 68 or so there will be unwanted heating in summer months if heating demand contact is still energized. Use of the optional indoor sensor is probably a good idea. One drawback, adjustment of desired indoor temp. is in the adjustment menu structure of the control by several button pushes, and the control it self will probably not be convenient to the living areas. The unit can be equipped with a remote timer which will allow for a occupied/unoccupied modes.
  • scott markle
    scott markle Member Posts: 17
    constant circulation

    Frank, I believe 260 is similar to 270 I just installed except that the 270 is for a modulating bioler. The 270 will operate the system in constant circulation mode provided the heat demand contact is energized. In my installation I wired this contact to a switch to allow the user to turn heat off in summer. There is a wwsd setting on the control but if its set to 68 or so there will be unwanted heating in summer months if heating demand contact is still energized.

    One drawback, adjustment of desired indoor temp. is in the adjustment menu structure of the control by several button pushes, and the control it self will probably not be convenient to the living areas. The unit can be equipped with a remote timer which will allow for a occupied/unoccupied modes.

    Constant circulation is for systems that can adjust their circulating temperatures fully. If you are not using a modulating condensing boiler you will need to incorporate a motorized mixing valve or injection mixing to provide the full temp. range required for constant circulation. In other words, if the boiler can only accept return water above 120 or so then when outside temps. don't require water this warm you will have to stop circulation or the space will be over heated. Still I'm told meaningful energy savings can be realized by reducing water temps. even if you cant go below the condensing threshold.
  • Dave_49
    Dave_49 Member Posts: 19
    Constant circulation

    why does constant circulation improve efficiency? I am on board with an outdoor reset. It seem with constant circulation you are using power to pump around water that is not always being heated. I seems to me that constant circulation would make a systems more comfortable, but not more efficient.
  • Uni R_3
    Uni R_3 Member Posts: 299
    Would this work?

    Could Frank use the 260 in a significantly different manner?

    Put the boiler on a small secondary loop. On the boiler loop is a circulator and a TRV low protection bypass. The boiler would also have a separate control fixed aquastat as a secondary control.

    Then mount the boiler sensor for the Tekmar on the heating loop and it could use full offset. An indoor sensor could also be incorporated.

    This would provide continuous circ with full outdoor reset at all temps while still offering full protection for the boiler loop via the TRV boiler bypass.

    Would that work?
  • Wayco Wayne_2
    Wayco Wayne_2 Member Posts: 2,479
    Are there

    microprocessor controls similar to the Buderus Logomatic that can be retrofited onto the Columbia boiler. I know Burhnam makes a control but have not used it so don't know the particulars. I know the Logomatic uses constant circ and outdoor reset along with an indoor feedback control to reset the outdoor reset.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • steve b_22
    steve b_22 Member Posts: 1


    Could it be only $.08/day? Isn't the calculation (75 watts*24hrs)/1000= 1.8 kwh/day? At our local (Boston)electric rate of $0.22/kwh that is more like $0.39/day or $90+/year
This discussion has been closed.