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Settings for Honeywell L6006C with HydroAir

don_163 Member Posts: 67
10.000 dollar question ain't it Dave? You'll have problem with the fan short cycling no matter what you do with these type of installs.Seen it/lived it.

One has to keep in mind with these type of system you have very little mass and fast try and handle the fan control thru a temp devise is like going back forty years when that is the only thing we had to work with.

Time has change Dave and speaking of time..time is what one should use with these type of install.

Add a simple fan on and off delay relay that is energize from the w termial at the stat and be done with it.

If you were to look at all the new hydro airhandler today all of them now uses a microprocessor that delay the fan for 45 seconds with a call for heat and off delay of 20 second after the call for heat ends.

As for the fan speed that to is not set in depend on temp rise and what your customer would perceive has cold air coming out of the vents.

Personally I would think high speed would be idea for efficency..however you have to keep in mind condensings the flue gases at high speed,but being this is a boiler system and you already have that in check at the boiler room then high speed it is as long as the temprise is up high enough not to chill the customer.

Hope this helps.


  • Dave_82
    Dave_82 Member Posts: 12
    Settings for Honeywell L6006C with HydroAir

    We have a hydroair blower which has a Honeywell L6006C 1018 aquatstat on the supply pipe at the coil. It keeps the fan blower from running until the water heats to a set temp. Currently, our boiler operating temp is about 180 degrees. What should we set the L6006C cutin temp (it's set at 130 degrees) as well as the differential (it's set at 5 now) to prevent short cycling of fan motor? Thanks. David
  • Is it blowing cold air

    when it comes on? If so gradually increase the temp to no higher than 150. Make sure if the air handler is variable speed that it is set up correctly for blower speed on heating. It is also important that air ducts are tight and insulated if passing through any cold spaces.
  • don_156
    don_156 Member Posts: 87

    We find they work much better on the return side.

    This way the whole coil is warm before the fan come on and it also give you a longer run time that assure all the heat is disapated before the fan shut down.

    140 with the lowest differential as possible.
  • Dave_82
    Dave_82 Member Posts: 12

    I will check to see whether it is on supply or return pipe. Why would you want a low differential? Wouldn't that contribute to short cycling of fan motor?
    Also, the air handlers are 3 speed (not variable speed). What should they be set at for heat (they're on low). How about a/c (should they be medium or high for a/c)?
  • L6006 The R-B break to R-W

    make temperature will be the set point temp in your case 130 degrees, plus the difference between the differential setting and 10 degrees (fixed differential on all switches).

    Make sure it is wired to the R-W terminals to bring the fan on.

    With the diff set for 5 degrees it will short cycle soooo Set differential to 25 Degrees set point to 140 degrees, this will cause R-B to break and R-W to make at 155 degrees bringing on the fan. The fan will then be shut off when temp drops to 130 degrees. This will cause your system to cycle from 130 degrees to 155 in the coil.

    To raise or lower the temperature then just change the set point. If you want a bigger spread increase the differential to 30 degrees.

    The important thing is to make sure it is wired correctly, 120 volt hot wired to terminal B and the terminal W to the fan motor. Terminal R is blank (no wire). The only difference would be if you are using R-B to feed a voltage back to your boiler.

    For heating set fan to low speed, for cooling to med or high speed.

  • Dave_82
    Dave_82 Member Posts: 12

    I looked at the fan unit that already has an L6006C on it, and there are only 2 wires. There is a black wire that goes from a terminal on the aquastat and connects to the power wire on the fan unit via a wire nut. Then there is a white wire that goes from the aquastat and connects to the wire to the fan motor.
    On the new unit, there is also some type of relay which has several connections for all the thermosts wires and 2 120 v black wires. It is located on the right of the picture with the 2 black wires and the wires with the small orange wire nuts.
    If I were to hook up the L6006C aquastat to this fan unit the way the other one is installed on my other fan unit, I would run a wire from the aquastat to the wire nut that has the 2 large red wires and the black wire at the upper right of the picture. But that black wire then travels to the relay on the right, and I have no idea what it does. In the other fan unit without that relay, there is no black wire. I would then run another wire from the aquastat to the wire nut that has the large red wire and the black wire on the lower left of the picture.
  • David I need a wiring diagram to be able to help you.

    It sounds to me like you have two different air handlers is that correct? I also understand that one is new is that correct? Did you install them?

    The L6006C control is a SPDT control R-B is normally closed and opens on a temperature rise. R-W is normallly open and closes on a temperature rise. You only need to break into the 120 volts which is fed to the fan motor with the R terminal and then run the wire from W to the fan motor.
  • Dave_82
    Dave_82 Member Posts: 12

    Tim, This is the new air handler that I'm trying to add an aquastat to, like the older one. I did not install it though.Here is the wiring diagram. It doesn't show it in the diagram, but there is the Honeywell relay to the right in the picture that somehow derives power from the black wire that is connected to the RD and RD/I wires in the diagram where I drew the arrow.
    The part # for the Honeywell relay is R8222D 1014
  • Does the fan come on when

    you turn the thermostat up for heating? If the answer is yes then you can wire the L6006 in series with teminal 3 on relay and the other side of L6006 wire to the Red wire going to the fan. This will give you temperature control on when the fan will come on.
  • Dave_82
    Dave_82 Member Posts: 12

    When the thermostst is turned up, the fan immediately comes on. So, the FDR (fan delay relay), terminal 3, I would remove that red wire (RD/3) from the relay and wire it to the L6006C and then wire the wire to the fan motor to the other wire coming from the L6006C? And these would hook to the R and W terminals on the aquastat? The wire to the motor is super heavy at least 8 gauge stranded. Do I need something that thick? The aquastat on the other air handler looks like it's wired with 12 gauge max.
    And that won't cause any problems with the a/c running in the summer?
    And since we're only using the R and W terminals on the aquastat, would I still set it at 140 with a differential of 25?
  • 12 gauge should be fine and

    yes use the settings I gave you and see how they do. It should be fine.
  • Don, the air

    handler has a time on time off built in as you say, by putting an aquastat control in the mix you can to some degree insure that the coil is hot enough to prevent blowing cold air. With any of these systems you have to keep adjustng until you get to the correct temp. A lot of times it is a trade off and also with air handlers sometimes they are in attics and the pipes tend loose heat if not insulated.

    I would hope the installer figured in static pressure loss and temperature rise in calculating the installtion. Without a variable speed blower you are sort of locked in for fan speeds. Again this requires some monitoring and adjusting.

    What do you typicaly see as a temperature rise on units that you install and also I find the 20 seconds shut down from the microprocessor a little quick, I will admit I have not seen all the air handlers there are on the market. What brands do you install?
  • Dave_61
    Dave_61 Member Posts: 271

    Thanks Tim.
    One thing I noticed that's weird....On the unit that already has the L6006C wired, the fan wasn't running today. I went upstairs and as soon as I removed the cover of the aquastat, the fan started. When I went to replace the aquastat cover, the fan stopped. The wiring is all behind the cardboard (nothing touching metal, but now the fan won't run with the cover on the aquastat.
  • Dave_82
    Dave_82 Member Posts: 12

    I have ordered the Honeywell L6006C from my local supplier and should get it next week. Since my air handler also runs for a/c in the summer, will interrupting the wire from the fan relay to the motor with the Honeywell cause problems in the summer by not allowing the fan unit to run in a/c mode?
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