89
14. Software upgrades will be accomplished by local download. Software upgrades through chip replacements are
not allowed.
15. Shall be shock resistant in all pl anes to 5G peak, 11ms during ope ration, and 100G peak, 11ms during storage.
16. Shall be vibration resistant in all planes to 1.5G @ 20 --300 Hz.
17. Shall support a bus length of 4000 ft (1219m) max, 60 devices per 1000 ft (305m) section, and 1 RS--485 repeat-
er per 1000 ft (305m) sections.
23 09 23.13.B. RTU Open -- Open protocol, direct digital controller:
1. Shall be ASHRAE 62--2001 compliant.
2. Shall accept 18--30VAC, 50--60Hz, and consumer 15VA or less power.
3. Shall have an operati ng temperature range from --40_F(--40_C) to 130_F(54_C), 10% -- 90% RH (non--condens-
ing).
4. Shall include built--in protocol for BACNET (MS/TP and PTP modes), Modbus (RTU and ASCII), Johnson N2
and LonWorks. LonWorks Echelon processor required for all Lon applications shall be contained in separate
communicat ion board.
5. Shall allow access of up to 62 network variables (SNVT). Shall be compatible with all open controllers.
6. Baud rate Controller shall be selectable using a dipswitch.
7. Shall have an LED di splay independently showing the status of serial communication, running, errors, power, all
digital output s, and all analog inputs.
8. Shall accept the following inputs: space temperature, setpoint adjustment, outdoor air temperature, indoor air
quality, outdoor air quality, compressor lock--out, fire shutdown, enthalpy switch, and fan status/filter status/
humidity/ rem ote occupancy.
9. Shall provide the following outputs: economize r, variable frequency drive, fan, cooli ng stage 1, cooling stage 2,
heat stage 1, heat stage 2, exhaust reversing valve/high fan speed.
10. Shall have built--in surge protection circuitry through solid state polyswitches. Polyswitches shall be used on
incoming power and network connections. Polyswitches will return to normal when the “trip” condition clears.
11. Shall have a battery back--up capable of a minimum of 10,000 hours of data a nd time clock retention during
power outages.
12. Shall have built--in support for Carrier techni cian t ool.
13. Shall include an EIA--485 protocol communication port, an access port for connection of either a computer or a
Carrier technician tool, an EIA--485 port for network communication to intelligent space sensors and displays,
and a port to connect an optional LonWorks communica tions card.
14. Software upgrades will be accomplished by either local or remote download. No software upgrades through chip
replacements are allowed.
23 09 33 Electric and Electronic Control System for HVAC
23 09 33.13 Decentralized, Rooftop Units:
23 09 33.13.A. General:
1. Shall be complete with self--contained low--voltage control circuit protected by a resetta ble circuit breaker on the
24--v transformer side. Transformer shall have 75VA capability.
2. Shall utilize color--coded wiring.
3. Shall include a centra l control terminal board to c onvenient ly and safely provide connecti on points for vital
control functions such as: smoke detectors, phase m onitor, gas controller, economizer, thermostat, DDC control
options, and low and high pressure switches.
4. The heat exchanger shall be controlled by an integra ted gas cont roller (IGC) microprocessor. See heat exchange r
section of this specification.
5. Unit shall include a minimum of one 8--pin screw termina l connection board for connection of control wiring.
23 09 33.23.B. Safeties:
1. Compressor over--temperature, over--current. High internal pressure differential.
2. Low pressure switch.
a. Units with 2 compressors shall have different sized connectors for the circuit 1 and circ uit 2 low and high
pressure switches. They shall physically prevent the cross--wiring of the safety switches between circuits 1
and 2.
b. Low pressure switch shall use different color wire than the high pressure switch. The purpose is to assist t he
installer and servi ce technician to correctly wire and or troubleshoot the rooftop unit.
To Next Page
Loading...
