KRACK FEV 11, Инструкция по установке и эксплуатации

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Fluid Cooler Series Air-Cooled Fluid Cooling Units (PN E208134_D)
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7.6 RELAY BOARD WIRING
Krack offers Emerson Multiflex boards, Danfoss, Microthermo, and Novar control boards with fluid
coolers with for A,B,C,E, and F fan motors. For units with K motors, Emerson Multiflex, Danfoss,
Microthermo, and HSM controller options are available. Review specific job drawing for further details.
Figure 19 Typical Relay Board Wiring –For 1 wide and 2 wide units.
1 Wide Units 2 Wide Units
7.7 Back Up Controller Wiring
Krack offers Johnson Controls System 350 as a backup controller. The operation of the fan cycle
controller employed with a fluid cooler unit should be set up so that the fan or set of fans if a double
wide unit, nearest the unit headers is/are the first fans on or last-off whenever the pump is running.
Not complying with this condition can cause uneven rapid expansion and contraction of the unit core
tubing contributing to tube failures. Violation of this condition is most often associated with electronic
controllers and must be avoided through correct programming. This also means do not program the
“header end” fans(s) for “equal run time.”
The excessive tube stress within the unit due to rapid expansion and contraction of the coil is caused by
needless temperature swings as a result of incorrect fan cycling during cold weather. The header end
fan(s) will cool the entering fluid and allow the remaining unit surface to cool the fluid at internal
temperatures that are not a threat to the performance of the equipment.
To obtain the maximum life from the unit, as well as meet with warranty stipulations, the following field
set-up is required:
A) Always set the header end fan(s) to cycle first-on and last-off when a pump is operating.
B) Do not set the fans to cycle-on more than 30 times per hour. The maximum short cycling is one
minute on, one minute off.