Reliatel MZVAV HP Information
Mechanical heat can be used for MWU or DWU
If no electric heat is installed TD5 display, BCI-R or BCI2R they will show it does not have heat.
ReliaTel MZVAV Heat Pump Operation
ReliaTel MZVAV HP units operate in a similar fashion as staged heat units with some differences. These units still support Daytime/Morning Warmup and Unoccupied Heating sequences using the same sequence of operation as staged heat units when the unit has a valid zone temperature.
MZVAV HP w/o Aux Heat
When viewing these units through BACnet, the following Analog Output setpoints for MWU/DWU will be missing:
- AO-4 Morning Warmup Setpoint BAS
- AO-5 Daytime Warmup Terminate Temperature Setpoint BAS
- AO-43 Daytime Warmup Initiate Temperature Setpoint BAS
Since these points are not present through BACnet, they have to be set on the RTAM module using the Morning Warmup Setpoint Dial R31. The setting of this dial determines the terminate setpoint for both MWU/DWU.
The Binary Output enable points will be present:
- BO-20 Morning Warmup Enable Command
- BO-21 Daytime Warmup Enable Command
If left out of service (out of service = true), MWU will be enabled all the time and DWU will follow the setting of SW1-5 on the RTAM, putting them in service (out of service = false) will allow the BAS to enable/disable the function. Fir 1.
Fig 1.
Morning Warmup Operation
MWU initiates when the unit is transitioning from unoccupied to occupied AND the space temperature active is 1.5°F less that the RTAM Morning Warmup Setpoint. If the criteria is met, the unit will start the fan at minimum speed, the OA damper will be commanded closed and the unit will start the 6 min VAV time delay. At the end of the time delay, the fan will ramp to 100% and the mechanical heating will run at 100%.
MWU terminates when the active space temperature is greater than RTAM Morning Warmup Setpoint OR 1 hour after initiate. When MWU terminates, the fan will ramp down to control duct pressure and the unit will transition back to cooling.
MZVAV HP w/ Aux Heat
When viewing through BACnet, the following points:
Analog Output setpoints for MWU/DWU will be present:
- AO-4 Morning Warmup Setpoint BAS
- AO-5 Daytime Warmup Terminate Temperature Setpoint BAS
- AO-43 Daytime Warmup Initiate Temperature Setpoint BAS
The Binary Output enable points will be present:
- BO-20 Morning Warmup Enable Command
- BO-21 Daytime Warmup Enable Command
If left out of service (out of service = true), MWU will be enabled all the time and DWU will follow the setting of SW1-5 on the RTAM, putting them in service (out of service = false) will allow the BAS to enable/disable the function. Fig 1.
Morning Warmup Operation w/ Electric heat
MWU initiates when the unit is transitioning from unoccupied to occupied AND the space temperature active is 1.5°F less that the RTAM Morning Warmup Setpoint.
If the criteria is not met after about 10 mins it will start staging the electric heat.
If the criteria is met, the unit will start the fan at minimum speed, the OA damper will be commanded closed, electric heat will shut off if it was enabled and the unit will start the 6 min VAV time delay. At the end of the time delay, the fan will ramp to 100% and the mechanical heating will run at 100%.
MWU terminates when the active space temperature is greater than RTAM Morning Warmup Setpoint OR 1 hour after initiate. When MWU terminates, the fan will ramp down to control duct pressure and the unit will transition back to cooling.
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.