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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?


  • carol_3
    carol_3 Member Posts: 397

    Is it short cycling now?
  • Dave_82
    Dave_82 Member Posts: 12

    It seemed to only run for a few minutes or so. I left it at 130 and raised the differential to 15. What do you think?
  • The R-B break and 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.

  • Dave_82
    Dave_82 Member Posts: 12

    I'll have to look at it again. This is a second air handler unit (we already have another air handler installed with an L6006C aquastat).
    I looked at the one that is presently hooked up, but our new air handler has some type of relay in the plenum where the air would flow through the water coil that has all the thermostat wires attached to it, as well as 2 black line voltage wires. Do you have any idea what that relay would be for? The other air handler has the thermostat wires wire-nutted directly to wires from the air handler (no relay).
    I can post a digital picture when i get home.
  • Relay is probably there

    to be able to give you switching between heating and cooling on the air handler.

    I suggest you get the contractor who installed the air handler to take a look at it.
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