Troubleshooting guide

OM 931-3 / Page 11 of 28
Tenant Override
Note: It is recommended that the "Occupied Operation" and
"Unoccupied Operation – Stand Alone Thermostat
Control" sections be reviewed prior to this section.
The MicroTech III unit controller enters tenant override
mode when the O terminal is energized for 3 seconds during
a period when the Water Source Heat Pump is in unoccupied
mode.
Tenant override allows a tenant, returning to the controlled
space after the unit has been placed in unoccupied mode, to
activate the tenant override input (O) and place the unit into
occupied mode.
Any remote button or switch with momentary dry contacts
can be used for this purpose. During the 2-hour tenant over-
ride period the W2 input will be ignored and the G, Y1, and
W1 inputs will be used (see "Occupied Operation" on page
7) for unit operation. If the U terminal is still grounded
after the 2-hour time limit, the unit will return to unoccupied
mode. Refer to "Unoccupied Operation – Stand Alone Ther-
mostat Control" on page 8.
Condensate Overow
Board LED Status – Condensate Overow
Y
ellow
Green
Red
On
Of
f
Of
f
The MicroTech III unit controller's condensate sensor is
designed to detect excessively high condensate water levels
in the drain pan. When high condensate water levels are
detected during cooling mode, the controller enters into
condensate fault mode. The fan operates normally during the
condensate overow fault mode.
Some faults and modes have higher priority than condensate
overow mode. See "Priority of Faults and Modes" on page
12 and Table 3 on page 12.
When the unit senses a condensate overow fault while in
cooling mode the following occurs:
1. The compressor de-energizes.
2. The fault terminal (A) de-energizes (fault). A to C will be
used to indicate an alarm signal.
When condensate levels return to normal, the controller will
automatically return to normal operation.
Remote Reset of Automatic Lockouts
The Remote Reset feature provides the means to remotely
reset some lockouts generated by high-pressure and/or low-
temperature faults. When the MicroTech III unit controller
is locked out due to one of these faults, and the cause of the
fault condition has been cleared, energizing the O-terminal
for 10 seconds or more forces the MicroTech III unit control-
ler to clear the lockout. Cycling unit power also clears a lock-
out if the conditions causing the fault have been alleviated.
Intelligent Reset (See Table 2)
The Intelligent Reset feature helps to minimize nuisance trips
of automatic lockouts caused by low-temperature faults. This
feature clears faults the rst two times they occur within a
24-hour period and triggers an automatic lockout on the 3rd
fault. The retry count is reset to zero every 24 hours.
Table 2: Faults
Fault Auto Recovery
Remote Reset Reset (Network
(Tenant Override) Command or Power)
Invalid Conguration Jumper Setting – – ●
Brownout ● – ●
HP1 ● ● ●
LP1 ●* ● ●
LT1 (In Heating) ●* ● ●
LT1 (In Cooling) – ● ●
Sensor Room Temperature, LT1, LT2,
– – ●
Failure EWT (w/Boilerless EH Only)
– – ●
Condensate Overow ● – ●
EEPROM Failure – – –
● = Applies – = Does not apply
* Auto Recover for the first two occurrences, lockout on the third occurrence within 24 hours, i.e., subject to “Intelligent Reset.”