York HFC-410A User Manual

JOHNSON CONTROLS

FORM 100.50-EG5 (108)

The control system for the YORK Eco² Packaged 
Rooftop Unit is fully self-contained and based around 
a Rooftop Unit controller. To aid in unit setup, unit con-
troller is equipped with a user visual LCD interface that 
consists of a 2 character above a 4-character display 
on the front of the Simplicity Elite control board. The two 
digit indicates the parameter of point number, and the 
4-digit displays the current value or setting such as time 
delay, cooling set point temperature, etc. This interface 
provides verifi cation of the systems operating status, 
enables fi eld installed options, and aids in troubleshoot-
ing system faults.

Four program buttons, located around the LCDs, allow 
the user to view and/or change 89 default parameter 
settings, acknowledge 42 alarm codes, and perform a 
unit run test. Up to fi ve (5) alarm Codes are displayed 
on the 4-character LCD. 

Greater access to programming can be gained through 
a Palm Pilot or Personal Computer (PC). Additionally, 
up to 64 of the Simplicity family of controllers can be 
networked together using a 3-conductor shielded cable 
to communicate with your PC via the available YORK 
recommended FREE net Serial Adapter and free YORK 
downloaded software.

An LED located on the lower center of the board provides 
a fl ash rate of 1 second (heart beat) when no alarms are 
present. A fl ash rate of 250 ms indicated that a current 
alarm is present. The LED lights up constantly if the 
board has failed and needs replaced, and will not light 
when the board power is lost.

See the YPAL unit Installation/Operations Manual (IOM) 
For 100.50-NOM6 (1107) for further Simplicity Elite 
technical information about the normal Sequence of 
Operation and user selectable options for our custom-
ized applications.

Some common selections include Occupied/Unoc-
cupied/recovery scheduling, equalized runtime for 
compressors, Morning warm-up, Economizer operation, 
Comfort, and Demand ventilation.

For the maximum in system fl exibility, the YORK Eco² 
Packaged Rooftop Unit can be operated by either a 
typical 7-wire thermostat (2 cool/2 heat), a space tem-
perature sensor, or stand-alone (VAV only). Note, a fi eld 
wiring terminal block is provided to facilitate unit setup 
and installation.

In lieu of the hard-wired control options, the rooftop 
unit controller can be connected to and operated by a 
Building Automation System (BAS). The Rooftop Unit 
controller is equipped with a Modbus (RTU) communica-

tion. Optional BACnet (MSTP) is available with a Modlinc 
translator, which allows communication to a BACNet 
(MSTP) based BAS.

Depending on application, the unit can be indexed 
between unoccupied and occupied modes of operation 
by one of three methods: hard-wired input, internal time 
clock, or BAS. A contact-closure input is provided for 
hard-wiring to an external indexing device such as a 
central time clock, thermostat with built-in scheduling, 
or a manual switch. The unit controller is also equipped 
with a built-in 7-day time clock which can be used, in 
lieu of the contact closure input, to switch the unit be-
tween Unoccupied and Occupied modes of operation. 
The internal time clock is fully confi gurable via the user 
interface and includes Holiday scheduling. In addition to 
the hard-wired input or the internal time clock, the unit 
can also be indexed between unoccupied and occupied 
modes of operation via BAS command.

Units supplied with gas heat can be equipped with one, 
two, or three independently operated burner modules. 
Each module is a fully self-contained furnace with all 
necessary ignition controls, safeties, and gas valves. 
The rooftop Unit Controller determines how the furnaces 
are started and stopped and prevents furnace operation 
if the Supply Fan airfl ow is not suffi cient or if the Supply 
Air Temperature is excessively high.

If a furnace module receives a signal to start from the 
Unit Controller, the ignition control engages the furnace 
inducer (draft) fan for a 30-second pre-purge cycle. At 
the end of the 30-second pre-purge, the ignition control 
will stop the furnace and allows the inducer fan to oper-
ate for a 30-second post-purge. Each furnace contains 
a direct-spark-ignition system and includes safeties for 
fl ame and inducer fan verifi cation, high temperature and 
fl ame roll-out.

Morning Warm-Up can be initialized by BAS or by the 
Unit Controller if the Intelli-Start is used. If the Intelli-Start 
is used, the Morning Warm-Up start time is calculated 
through an adaptive algorithm.

When Morning Warm-Up is required, the Unit Controller 
energizes the VAV heat relay, starts the Supply Fan and 
qualifi es the Return Air Temperature for 5 minutes.

The internal heat source (Gas, HW/Steam, or Electric) 
is controlled to maintain the Return Air Temperature to