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VAV Quick Setup for Temporary Operation

Updated

VAV Quick Setup for Temporary Operation

 

Test Mode

The supply fan will start at the 3rd step of test mode.

  1. The indoor fan will be controlled to the supply pressure setpoint unless test mode has been running for 6 minutes or longer.
  2. Heat will not be allowed to come on until the unit has been in test mode for at least 6 minutes and the indoor fan is at 100%.

 

Cooling

The simplest way to get cooling on a VAV with Reliatel controls is to install a jumper wire on the RTRM between terminals J6-2 and J6-4. The RTRM J7 inputs (R, Y1, W1, G, W2 & Y2) do not work on a VAV Unit.

  1. The unit will use the setpoints on the RTAM.
    • Set the Supply Air Cooling Setpoint to 55° (this is the temperature of the air that will be coming out of the unit)
    • Set the Static Pressure Setpoint to 1.25 (12 o’clock position)
    • Set the Static Pressure Deadband to 0.5 (12 o’clock position)
  2. The wind bird (Dwyer A-306 Static Pressure Sensor) must be installed for proper unit operation.    

 mceclip7.png    mceclip1.png        mceclip3.png        mceclip4.png

 

Notes:

With this set up, if there is no jumper between J6-2 & 4 the unit mode is "OFF".

With a J6-2 & 4 jumper the unit mode is "AUTO".

 

Heat

Unless a 10KΩ @ 77° sensor is installed on the RTRM J6-1 & 2, the unit will only operate in the discharge air cooling mode.

For temporary operation the sensor can be thrown in the Return Section of the unit.

(The unit will not go into morning or daytime warmup mode without the sensor)

  1. Set Morning Warmup Setpoint to the desired space temperature.
  2. Be sure to wire VHR Relay Output to drive the VAV Boxes wide open in Morning Warmup.
    1. Voyager - LTB-15(C), 16(NO) and 17(NC)
    2. Precedent - VHR-1(NC), 4(NO), 7(C)
  3. During the Morning Warmup cycle, the unit runs at 100% airflow until the Morning Warmup Setpoint is reached or 60 minutes have elapsed, whichever comes first.
  4. If 60 minutes have elapsed and the space temperature is still at least 3°F below the Morning Warmup Setpoint, the unit will continue to heat in the Daytime Warmup mode until the MWU setpoint is reached, however, if DWU is disabled at the RTAM, the unit will transition into cooling mode regardless of the zone temperature.

 

Notes:

Morning Warmup occurs when the unit transitions from unoccupied mode to occupied mode and the zone temperature is at least 1.5F lower than the Morning Warmup setpoint.

  1. RTRM J6-11 & 12 Open is occupied, Closed is unoccupied.
  2. If the unit is using a BAYSENS119 zone sensor, the Warmup Setpoint on the BAYSENS119 is the Morning Warmup Setpoint.
  3. Using a BAYSENS924 on a Multi-zone unit is not supported.
  4. If you wire a mechanical zone sensor to RTRM J6-5, the unit will still use the RTAM Morning Warmup Setpoint unless you cut jumper R75 (on the RTAM Board) 

Daytime Warmup is applicable during occupied status and when the zone temperature is 3° below the Morning Warmup Setpoint on the RTAM. (The termination setpoint is equal to the Morning Warmup setpoint)

  1. Daytime Warmup can be activated by Set SW1 dip switch #5 on the RTAM to ON (up position)
  2. When the zone temperature meets or exceeds the termination setpoint the unit will revert to the cooling operation.

  3. VHR Relay
    When the unit transitions from occupied mode to morning warm-up, daytime warm-up or unoccupied mode, the VHR relay is energized, as long as the unit has a valid zone temperature input at RTRM J6 1&2, or through a BAYSENS020* zone sensor.

     

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    The VHR relay has a set of contacts on TB3 for the purpose of commanding the VAV boxes to drive open to maximum airflow position. If the unit has heat, the VAV boxes must be driven open. If the boxes are allowed to stay in control, the boxes may try to close instead of open when the warm air enters the room.
    • When RTAM DIP SW1-1 is on, the output voltage range is approximately 0 to 10.5VDC.
    • When RTAM DIP SW1-1 is off, the output voltage range is approximately 2.5 to 8.5VDC.
    • IGV: When the supply fan is on and the output is 0%, the IGV are closed.
    • VFD: When the supply fan is on and the output is 0%, the VFD runs at 35hz.
    • If the supply static pressure goes below -0.2" (0.2VDC) the IGV / VFD output will stay at 0% and
    the diagnostic COOL FAIL + SERVICE FAIL will be present.
    • If the static pressure exceeds 3.8" WC the supply fan will stop and the diagnostic HEAT FAIL + COOL
    FAIL +SERVICE FAIL will be present.
    • During the heating modes; Daytime Warm-up, Morning Warm-up, and Unoccupied, the IGV or VFD output is always 100%.

 

 

WARNING:

Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.

 

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