VAV w/ Reheat (Parallel Fan) Profile

4 Minute Read

| Overview

VAV with Reheat- No Fan) is a terminal profile that uses a SmartNode to control a terminal VAV box. The profile supports both the cooling and heating requirement for a zone.

Based on the system-level equipment, AHU or RTU is in cooling mode or Heating mode the damper and reheat operations enabled provide the optimum results for the zone based on the zone load.

The VAV with Reheat- No Fan allows the choice of dampers, reheat based on the equipment used, and the zone priority which equates to the importance multiplier in guideline 36.

On the heating side, the profile supports both the staged & modulating reheat controls.

Quick Summary
Damper Control	Reset based on Space Temperature and/or  CO2 and/or CFM & mode of operation.
Reheat Control	Reset based on Space Temperature & mode of operation at the system level
Parallel Fan Speed Control	Reset based on Space Temperature and/or  CO2 and/or CFM & mode of operation.

| Wiring

Wiring Schematic for Staged Reheat

User 18-gauge thermostat wire for power and actuator connections.

I/O
VAV Reheat - Parallel Fan - Staged Electric RH
Inputs/ Outputs
#	DI	AI	DO	AO	Point	Comments
AI1		X				0-10Vdc
AI2		X				0-10Vdc
TH1		X			Discharge Air Temp	10k Type II or DI
TH2		X			Entering Air Temp	10k Type II or DI
AO1				X	Damper Actuator	0-10Vdc
AO2				X		0-10Vdc
R1			X		Reheat Stage 1	Dry contact
R2			X		Parallel Fan	Dry contact
Other Ports
Damper 1	8 Pin RJ45					Primary Smart Damper
Damper 2	8 Pin RJ45					Secondary Smart Damper
RTS	3 Pin Molex Sensor Bus				Temperature/ Humidity/ Duct Pressure	3 pin cable connector (No local interface option)
RS485	4 Pin Molex Sensor Bus				Temperature/ Humidity Local control	4 pin cable connector (Local Interface option)

Modulating Reheat

I/O
VAV Reheat - No Fan - Modulating Reheat
Inputs/ Outputs
#	DI	AI	DO	AO	Point	Comments
AI1		X				0-10Vdc
AI2		X				0-10Vdc
TH1		X			Discharge Air Temp	10k Type II or DI
TH2		X			Entering Air Temp	10k Type II or DI
AO1				X	Damper Actuator	0-10Vdc
AO2				X	Modulating Reheat	0-10Vdc
R1			X			Dry contact
R2			X			Dry contact
Other Ports
Damper 1	8 Pin RJ45					Primary Smart Damper
Damper 2	8 Pin RJ45					Secondary Smart Damper
RTS	3 Pin Molex Sensor Bus				Temperature/ Humidity/ Duct Pressure	3 pin cable connector (No local interface option)
RS485	4 Pin Molex Sensor Bus				Temperature/ Humidity Local control	4 pin cable connector (Local Interface option)

| Configuration Steps

To configure a VAV with Reheat (No Fan) profile 

• Click the pair module from the floor layout screen.

• Click the SN (SmartNode) from the select device type, screen.

 

• Click the VAV with Reheat from the select module type, screen.

• Select the VAV Reheat- No Fan.

• Click Pair, to pair the device using the pairing instructions on the pairing steps screen.

• Select the device MAC address relayed for pairing, or click connect manually to pair the device manually. For more information on manual pairing refer to Alternate/ Manual Pairing for SmartNode.

• Enter the pin displayed on the SmartNode device or an automatic pairing.
• Click Pair.

| Know Your Profile

Intro Video Placeholder

The profile configuration screen is displayed as below.

 

| Configuration Parameters

The following are the parameters made available in the configuration screen.

For a Temperature control with Auto Force Occupied & Auto Away Disabled.

Parameter	Purpose	Default Value	Values in the drop-down list
Damper Type	To define the type of damper used	0-10V	0-10V, 2-10V, 10-2V, 10-0V, Smart Damper, 0-5V
Size	To define the damper size used	4	4 to 22 in increments of 2
Shape	To define the damper shape	Round	Round, Square, Rectangular
Reheat Type	To define the reheat type used	Not installed	Not installed, 0-10V, 2-10V, 10-2V, 10-0V, Pulsed Electric, Stage1, Stage 2
Zone Priority	To define the zone's importance multiplier, for more information refer to Damper Position & Zone Priority Driven Trim and Respond Requests.	Normal	None, Low, Normal, High
Thermistor 1	To include a Discharge airflow temperature sensor	NA	NA
Thermistor 2	To include a Supply airflow temperature sensor	NA	NA
Temperature Offset	To define a temperature offset for the profile	0	-10 to 10 in increments of 0.1
Max Damper Pos Cooling	To define a maximum damper position percentage during cooling operation	100	0 to 100 % in increments of 1%
Min Damper Pos Cooling	To define a minimum damper position percentage during cooling operation	20	0 to 100 % in increments of 1%
Max Damper Pos Heating	To define a maximum damper position percentage during heating operation	100	0 to 100 % in increments of 1%
Min Damper Pos Heating	To define a minimum damper position percentage during heating operation	20	0 to 100 % in increments of 1%

For temperature-based control with Auto Force Occupied & Auto Away enabled

Parameter	Purpose	Default Value	Values in the drop-down list
Auto Force Occupied	To enable conditioning if the space is occupied outside the  building scheduled hours	Disabled	NA
Auto Away	To stop conditioning if the space is not occupied during the building's scheduled hours	Disabled	NA

For Temperature & CO2 Based Control 

Parameter	Purpose	Default Value	Values in the drop-down list
Enable CO2 control	To enable CO2 based control complementing the temperature based control for more information refer VAV Terminal Profile- Damper Position Calculation & Operation	Disabled	NA

For Temperature CFM based control

Parameter	Purpose	Default Value	Values in the drop-down list
Enable CFM control	To enable CFM based control, complementing the temperature & CO2 based controls, for more information, refer to VAV Terminal Profile- Damper Position Calculation & Operation	Disabled	NA
Max CFM Cooling	To define maximum CFM levels during cooling operation	250	0 to 5000 CFM in increments of 5 CFM
Min CFM Cooling	To define minimum CFM levels during cooling operation	50	0 to 5000 CFM in increments of 5 CFM
Max CFM Reheating	To define maximum CFM levels during reheat operation	25	0 to 5000 CFM in increments of 5 CFM
Min CFM Reheating	To define minimum CFM levels during reheat operation	50	0 to 5000 CFM in increments of 5 CFM

• Click Set to confirm the configurations.

| Configuration

Once you've paired the SmartNode as a VAV profile, the sequences for VAV applications in GPC36 will be followed. What you will need to do is select a few specific configuration parameters that define the physical characteristics of your box.