Vcm & vcm-x controllers, Vcm & vcm-x static & staging, Smts ii technical guide – Orion System System Manager TS II In-House User Manual

Page 37

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SMTS II Technical Guide

VCM & VCM-X Controllers

37

Setpoints for Unit 0102

Minimum Outdoor Air Content

10

Static & Air Setpoints

Page 5 of 5

Maximum Outdoor Air Content

50

%

Ambient Outdoor C

Level

O2

400

PPM

Altitude

500

Ft

C

Fail Mode Offset

O2

0

%

%

Figure 60: VCM-X Static & Air Setpoints Screen 5

VCM & VCM-X Static & Staging

Minimum Outdoor Air Content

If Demand Ventilation is being used, this is the minimum outdoor air content
required to provide the minimum ventilation requirements. High Limit =
100%; Low limit = 1%; Default = 10%.

Maximum Outdoor Air Content

If Demand Ventilation is being used, this is the maximum outdoor air content
required to provide the minimum ventilation requirements. High Limit =
100%; Low limit = 1%; Default = 50%

Ambient Outdoor CO2 Level

Enter the ambient CO

2

level for the outdoor air conditions in the area

where this unit is installed. High limit = 1000 PPM; Low limit = 0 PPM;
Default = 400 PPM.

Altitude

Enter the altitude or elevation above sea level for the location of the build-
ing this unit is installed in. High limit = 15,000 feet; Low limit = 0 feet;
Default = 500 feet.

CO2 Fail Mode Offset

If communication is lost with the polling device, this offset will be added to
the minimum economizer position, in an attempt to maintain minimum ven-
tilation requirements. High Limit = 100%; Low limit = 0%; Default = 0%.

Staging Delays Setpoints

Touch the

< Staging Delays>

button to access the Staging

Delays Setpoint Screens.

Staging

Figure 61: VCM-X Staging Delays Setpoints Screen 1

Cooling Stage Down

This is the amount of time that must elapse between each Compressor
deactivation to prevent all Compressors from deactivating at once as the
cooling demand decreases. High limit = 15 minutes; Low limit = 1 minute;
Default = 1 minute.

Cooling Stage Up

This is the amount of time that must elapse between each Compressor
activation to prevent all Compressors from activating at the same time due
to large cooling demands. High limit = 15 minutes; Low limit = 3 minutes;
Default = 3 minutes.

Cooling Min Run Time

This is the minimum amount of time the Compressors must remain on once
they have been activated. This overrides the Stage Down Delay if that is
not as long as this delay. High limit = 15 minutes; Low limit = 5 minutes;
Default = 5 minutes.

Cooling Min Off Time

Once a Compressor has been staged back off, it must remain off for this
amount of time to prevent short cycling. High limit = 15 minutes; Low
limit = 3 minutes; Default = 3 minutes.

Mechanical Fail Timeout

When Heating or Cooling Mode is initiated and staging is activated, if the
Supply Air Temperature does not rise or fall 5°F within the Mechanical
Fail Timeout Setpoint, a Mechanical Heating or Cooling failure alarm will
be generated. The Alarm is for status reporting only. The HVAC unit will
continue to run. High limit = 255 minutes; Low limit = 0 minutes; Default
= 15 minutes.

Figure 61: VCM-X Staging Delays Setpoints Screen 2

Heating Stage Down

This is the amount of time that must elapse between each Heat Stage
deactivation to prevent all Heat Stages from deactivating at once as
the heating demand decreases. High limit = 15 minutes; Low limit = 1
minute; Default = 1 minute.

Heating Stage Up

This is the amount of time that must elapse between each Heat Stage
activation to prevent all Heat Stages from activating at the same time
due to large heating demands. High limit = 15 minutes; Low limit = 3
minutes; Default = 3 minutes.

Heating Min Run Time

This is the minimum amount of time the Heat Stages must remain on
once they have been activated. This overrides the Stage Down Delay
if that is not as long as this delay. High limit = 15 minutes; Low limit
= 2 minutes; Default = 2 minutes.

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