Specifications

IM 1049-4 / Page 33 of 36
To avoid electrical shock, personal injury or death, be sure that
eld wiring complies with local and national re, safety, and elec-
trical codes, and voltage to the system is within the limits shown
in the job-specic drawings and unit electrical data plate(s).
Power supply to unit must be disconnected when
making eld connections. To avoid electrical shock, personal
injury or death, be sure to rigorously adhere to eld wiring pro-
cedures regarding proper lockout and tagout of components.
DANGER
General Use and Information
The Microtech III unit controller is provided with two drive
terminals,R(24VAC)andC(0VAC)thatcanbeusedbythe
end user to drive the thermostat inputs (G, Y1, Y2, W1, and
W2)andcontrolinputs(U,E,andO).Anycombinationofa
singleboarddriveterminal(RorC)maybeusedtooper-
atetheMicroTechIIIunitcontroller’scontrolorthermostat
inputs.However,onlyonedriveterminal(RorC)canbe
connected to any individual input terminal or damage may
result.Somecontrolinputsarenotaccessibletotheenduser
(for example, HP, LP, SLTS, and COF).
TypicallytheMicrotechIIIunitcontroller’sR(24VAC)ter-
minalisusedtodrivetheboard’sthermostatinputsandcon-
trolinputsbyconnectingittotheRterminalofanindustry
standard thermostat. The control outputs of the standard ther-
mostat are then connected to the Microtech III unit controller
thermostat inputs and control inputs as needed. Any remain-
ingboardinput(s)maybeoperatedbyadditionalthermostat
outputs or remote relays (dry contacts only).
AllMicrotechIIIunitcontrollerinputsmustbeoperatedby
drycontactspoweredbythecontrolboard’spowerterminals.
Nosolidstatedevices(Triacs)maybeusedtooperatethe
Microtech III unit controller inputs. No outside power source
maybeusedtooperatetheMicrotechIIIunitcontroller
inputs.