OMM 1130 49
Any signal less than 4 mA does not limit the chiller capacity.
Network Limit
The maximum unit capacity can be limited by a network signal. This function is only enabled if the unit
control source is set to network. The maximum unit capacity stage is based on the network limit value
received from the BAS, and is determined as shown in the following graph.
In order to allow all stages to run, a signal of 100.0% is required.
Maximum LWT Rate
The maximum rate at which the leaving water temperature can drop is limited by the Maximum Pull
Down Rate set point when the unit mode is cool. If the rate exceeds this set point, no more compressors
shall be started until the pull down rate is less than the set point. Running compressors will not be
stopped as a result of exceeding the maximum pull down rate.
Low Ambient Lockout (Water Cooled = NO Only)
If the OAT drops below the low ambient lockout set point, then all running circuits will do a normal stop,
after the compressors have stopped the evaporator water pump will stop. Once the lockout has been
8.0 12.0 16.0
3
4
5
6
4.0 6.7 14.7 17.312.0
Limit Signal (%)
Max
Stage
9.3 20.0
2
1
0
Limit Signal vs. Max Stage
(with 4 compressors)
Limit Signal vs. Max Stage
(with 6 compressors)
3
4
4.0
Limit Signal (%)
Max
Stage
20.0
2
1
0
25.0 50.0 75.00 100.0
0 16.7 66.7 83.450.033.3 100.0
Limit Signal (mA)
Limit Signal (mA)
25.0 50.0 75.0
3
4
5
6
0 16.7 66.7 83.450.0
Max
Stage
33.3 100.0
2
1
0
Network Limit vs. Max Stage
(with 4 compressors)
Network Limit vs. Max Stage
(with 6 compressors)
3
4
0
Network Limit (%)
Max
Stage
100.0
2
1
0
Network Limit (%)
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