sequence of
Operation operation
Sequence of Operation Tracer ZN010 and ZN510
Note: this section applies only to units with a Tracer ZN010 or ZN510 controller.
Power-Up Sequence
When 24 VAC power is initially applied to the Tracer ZN010 or ZN510, the following sequence occurs:
Table
unit type | EWT sensor required? | coil water temperature |
|
|
yes | COOLS if: space temp - EWT ≥ |
| 5°F | |
|
| HEATS if: EWT - space temp ≥ |
| 5°F |
yes | COOLS if: space temp - EWT ≥ | 5°F | ||
|
| HEATS if: EWT - space temp≥ | 5°F | |
|
|
|
|
|
no | hot water assumed |
|
| |
no | cold water assumed |
|
| |
no | cold water assumed in main coil | |||
|
| hot water assumed in aux. coil | ||
1.All outputs are controlled off.
2.Tracer ZN010 and ZN510 reads all input values to detemine initial values.
3.The random start time
4.Normal operation begins.
Entering Water Temperature Sampling Function
Both Tracer ZN010 and ZN510 use an entering water temperature sampling function to test for the correct water temperature for the unit operating mode. For all applications not involving changeover, the water temperature does not affect unit operation.
The entering water temperature sam- pling function opens the main hydronic valve, waits no more than three minutes to allow the water temperature to stabilize, then measures the entering water temperature to see if the correct water temperature is available.
The entering water must be five degrees or more above the space temperature to allow hydronic heating and five degrees or more below the space temperature to allow hydronic cooling.
If the correct water temperature is available, the unit begins normal heating or cooling operation. If the measured entering water temperature is too low or high, the controller closes the valve and waits 60 minutes before attempting to sample the entering water. Reference Table
Binary Inputs
BIP1: Low Temperature Detection Option
The factory hard wires the low temperature detection sensor to binary input #1 (BIP1) on the Tracer ZN010 and ZN510. The sensor defaults normally closed (N.C.), and will trip off the unit on a low temperature diagnostic when detecting low temperature. In addition, the Tracer ZN010 and ZN510 control unit devices as listed below:
fan: off
valves: open
electric heat: off
damper: closed
Note: See the “Diagnostics” section for more information.
BIP2: Condensate Overflow Detection Option
The factory hard wires the condensate overflow sensor to binary input #2 (BIP2) on the Tracer ZN010 and ZN510. The sensor defaults normally closed (N.C.), and will trip off the unit on a condensate overflow diagnostic if condensate reaches the trip point. In addition, the Tracer ZN010 and ZN510 control unit devices as listed below:
fan: off
valves: closed
electric heat: off
BIP3: Occupancy Sensor
Binary input #3 (BIP3) on Tracer ZN010 and ZN510 is available for field- wiring an occupancy sensor, such as a binary switch or a timeclock, to detect occupancy. The sensor can be either normally open or normally closed. Reference Table
Binary Outputs
Reference Table
Table
binary output | description | pin |
BOP1 | fan high speed | |
BOP2 | fan medium speed | |
BOP3 | fan low speed | |
BOP4 | main valve | |
BOP5 | auxiliary valve/electric heat | |
BOP6 |
Notes:
1.In a
2.If no valves are ordered with the unit, the factory default for the Tracer ZN010 and ZN510 controller are:
BOP4 configured as normally closed BOP5 configured as normally open
3.If the fresh air damper option is not ordered on the unit, BOP6 will be configured as none.
Table
sensor type | sensor position | unit occupancy mode |
normally open | open | occupied |
normally open | closed | unoccupied |
normally closed | open | unoccupied |
normally closed | closed | occupied |
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