McQuay MicroTech II Operation Manual page 106

Table 63: Unit Does Not Startup and Run at All:
Problem
1. Unit does not leave the Off Unoc operat-
ing state. (UnitStatus= parameter in the
System menu indicates "Off Unoc" and
unit does not start.)
2. Unit does not leave the Off Sw operating
state. (UnitStatus= parameter in the Sys-
tem menu indicates "Off Sw" and unit
does not start.)
106
1.1. Check Occupancy= parameter in Occupancy menu:
1. If the Occupancy = parameter in the Occupancy menu indicates
either "Occ" or "Bypass" and the unit remains in the Off Unoc
operating state, MCB is likely defective
2. If the Occupancy = parameter in the Occupancy menu indicates
"Unocc" refer to Item 1.2 below.
1.2. Check Occ Mode= parameter in the Occupancy menu:
1. If the Occ Mode= parameter is set to "Unocc", the unit starts only
if unoccupied heating (night setback) or unoccupied cooling (night
setup or purge) operation is active. Refer to "Unoccupied Control"
on page 89.
2. If the Occ Mode= parameter is set to "Auto", the unit starts only if
at least one of the following are true:
a) Field time clock terminals 101 to 102 on TB2 in the main con-
trol box are made (binary input MCB-BI1 is on). Refer to
"External Time Scheduling" on page 51.
b) Internal time schedule indicates an occupied period. Refer to
"Internal Daily Scheduling" on page 49.
c) Holiday time schedule indicates an occupied period. Refer to
"Holiday Scheduling" on page 49.
d) One event schedule indicates an occupied period. Refer to
"One Event Scheduling" on page 49.
e) Network time schedule indicates an occupied period. Refer to
"Network Time Scheduling" on page 51.
f Unoccupied heating (night setback) or unoccupied cooling
(night setup or purge) operation is active. Refer to "Unoccu-
pied Control" on page 89.
If any one of items a) through f) is true and the Occupancy=
parameter in the Occupancy menu still indicates "Unocc" and the
unit remains in the "Off Unoc" operating state, MCB is likely
defective.
2.1. Check terminals 101 and 104 on TB2 in the main control box:
1. The unit is disabled and remains in the Off Sw operating state
when terminal 101 is made to 104 on TB2 (binary input MCB-BI2
is on).
2. If terminal 101 is not made to 104 on TB2 (binary input MCB-BI2
is off) and the UnitStatus= parameter continues to indicated "Off
Sw", MCB is likely defective.
Check
OM 138