Echo 8870 Step, Disconnect Power To All Hvac Equipment And/Or Zone Control Panels

MODEL 8870 THERMOSTAT

The Model 8870 Thermostat is field configurable to operate single and multi-stage separate heating and cooling equipment (such as furnace and air conditioner or roof top units), or single and multi-stage heat pump systems. A menu driven set up, using the message center display of the thermostat, can be used to configure many other features.

Network communication is non-isolated, full duplex RS-485 (RS-422). The ‘A’ terminals are the transmit pair while the ‘B’ terminals are the receive pair. This nomenclature uses the computer or host as the reference, so transmit refers to the lines on which the host transmits data to the thermostat while receive refers to the lines on which the host receives data from the thermostat. The baud rate is selectable between 9600 and 19200. Up to 64 uniquely addressed thermostats may reside on the same thermostat network.

MODEL 8818 DISTRIBUTION PANEL

The Distribution Panel is a switch controlled communication bus that can be wired to eight (8) Aprilaire Model 8870 thermostats. This allows thermostat communication (transmit, receive or both) to be turned on and off at one convenient location which simplifies installation and trouble shooting. Each thermostat station on the distribution panel has an on/off switch for power. This allows isolation of any one thermostat to simplify troubleshooting. Order one Distribution Panel per eight thermostats.

MODEL 8061 AND MODEL 8062 SUPPORT MODULES

Support modules are used to either monitor or control temperature or humidity at a location other than the thermostat. They communicate with the thermostat using a RS-485 protocol. Up to four support modules may be wired to a thermostat, with each module able to support two sensors. The Model 8061 has one onboard temperature sensor and room for one offboard temperature sensor (sensor #1 & sensor #2) while the Model 8062 has one onboard temperature sensor (sensor #1) and one onboard humidity sensor (sensor #2). All sensors can be configured as either a control sensor (replaces thermostat temperature sensor as control variable) or a monitor sensor (read only). An offboard sensor such as a Model 8051 Flush Mount Sensor can replace sensor #1 on the Model 8062 or both on the Model 8061. Each support module is addressed and each sensor value can be accessed through thermostat commands. See sensor literature for additional information.

FOR EASE OF INSTALLATION AND TROUBLE SHOOTING DO THE FOLLOWING:

✔Use Category-5 cable for all communication wiring.

✔Check and recheck to ensure connection to the proper terminals before powering up the thermostats. Use wire color as a guide and be consistent.

✔Use a Distribution Panel on all systems with more than one zone. The trouble shooting benefits will outweigh the cost of the Distribution Panel.

Step 2

DISCONNECT POWER TO ALL HVAC EQUIPMENT AND/OR ZONE CONTROL PANELS

•If the thermostats are wired to a zone control panel, there is generally one set of input terminals supplying power to the thermostats and dampers. This must be disconnected.

•If the thermostats are wired directly to HVAC equipment, the power must be shut off at the equipment. This can generally be accomplished by turning off the disconnect switch located near the equipment. If an obvious disconnect switch is unavailable, you will need to turn the circuit off using the fuse or circuit breaker. Remove the fuse or shut down the circuit breaker serving the equipment.

CAUTION

Failure to disconnect power could result in damage to the HVAC equipment or thermostats. Leave power disconnected until all other electrical connections have been made and checked for accuracy.

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