Hired-Hand Farm Hand Series: Heat Zone - Manual (Page 10)

Part No. 4801-5129 rev 6-04 Farm Hand Heat Zone 8
Note: In step 2, it very important to remove electrical power
from the circuits connected to the relay board, since
external equipment may back-feed voltage through the
relay board!
CAUTION !
2) Remove power from the equipment connected to the relay strip to be replaced.
3) Unplug the Stage harness cables from the relay board.
4) Use needle nose pliers to pinch the tops of the mounting tabs to release the relay strip.
5) Verify that the replacement relay strip is of the Normally Open (N.O.) type. Fail-Safe types
of relay strips are not recommended in heating. See the insert below that describes how to
recognize the two types of relay strips.
6) Install new relay strip by pressing evenly near the mounting tabs.
7) Re-install the stage harness cables.
FAIL-SAFE
strips are labeled at the
top of the board.
When replacing any
Relay Strip be sure to
verify the type.
NORMALLY OPEN
(N.O.)
strips are labeled at the
bottom of the board.
Inset
(Top)
(Bottom)
HEAT
COOL 3
COOL 2
COOL 1
RPK
COOL 3
COOL 2
COOL 1
HEAT
FAIL-SAFE RELAY STRIP
COOL 3
COOL 2
COOL 1
HEAT
B Cr
ider
N.O.RELAY STRIP
WHAT ARE FAIL-SAFE RELAY STRIPS ?
There are two types of Relay Strips. The Normally Open (N.O.) strip
requires a signal from the controller board in order to energize a stage
of ventilation. Should power be removed from the controller, the
Normally Open Relay board would not be able to energize a ventilator.
On the other hand, the Fail-Safe relay strip would close each of the
relays in the strip resulting in energizing the ventilators in case of a
controller power failure.
NOTE: Fail-Safe relay strips are NOT recommended for
heating (brooder) applications!