McQuay AGZ 010BS User Manual

46 AGZ 010B through 034B IOMM AGZB1
ALSO
If Unit Mode = Cool, AND
At least one compressor is running, AND
LWT error > Upper Control Band, AND
Pulldown rate <= Max pulldown rate, AND
Compressors running < unit capacity limit, AND
Stage up timer is expired, THEN
Stage Up Now = True
ALSO
If Unit Mode = Ice, AND
no compressors are running, AND
LWT error > Start delta + Upper Control Band, AND
Motor Protect Timer is expired, AND
Ice Delay Timer is expired, AND
Stage up timer is expired, THEN
Stage Up Now = True
ALSO
If Unit Mode = Ice, AND
LWT error > 0, AND
At least one compressor running, THEN
Stage Up Now = True
Stage Down Now
The Stage Down Now flag is set based on the following tests:
If Unit Mode = Cool, AND
LWT error < -(Lower Control band), AND
More than one compressor is running, AND
Stage down timer is expired, THEN
Stage Down Now = True
ALSO
If Unit Mode = Cool, AND
LWT error < -(Lower Control band) - stop delta, AND
One compressor is running, AND
Stage down timer is expired THEN
Stage Down Now = True
ALSO
If Unit Mode = Cool, AND
Number of compressors running > Demand limit, AND
Stage down timer expired, THEN
Stage Down Now = True
ALSO
If Unit Mode = Ice, AND
LWT error < 0, THEN
Stage Down Now = True
Compressor Sequencing
Compressor staging is based primarily on compressor run-hours and starts. Compressors
that have less starts will normally start before those with more starts. Compressors that
have more run-hours will normally shut off before those with less run-hours.

McQuay AGZ 010BS Specifications

General

Brand	McQuay
Model	AGZ 010BS
Category	Chiller
Language	English