Carrier 50HQ User Manual download pdf (Page 31)

h. Unit shutdown on high or low water temper-

ature (selectable for antifreeze solutions).

i. Option to reset unit at thermostat or discon-

nect. Fault type shall be retained in memory

if reset at thermostat.

j. Automatic intelligent reset. Unit shall auto-

matically restart 5 minutes after shutdown if

the fault has cleared. Should a fault occur

3 times sequentially, then lockout will occur.

k. Ability to defeat time delays for servicing.

l. Light-emitting diode (LED) to indicate high

pressure, low pressure, improper voltage,

water coil freeze protection, air coil freeze

protection, condensate overflow, and con-

trol status.

m. Unit Performance Monitor to indicate ineffi-

cient operating conditions prior to unit

lockout.

n. Remote fault type indication at thermostat.

o. Single harness connection for all safety

devices.

p. Selectable 24-v or pilot duty dry contact

alarm output.

q. 24-v output to cycle a motorized water valve

with compressor contactor.

3. The optional Deluxe D electronic control shall

have all the features of the Complete C control,

with the following additional features:

a. A removable thermostat connector.

b. Random start on return from night setback.

c. Minimized reversing value operation for

extended life and quiet operation.

d. Night setback control from low temperature

thermostat, with 2-hour override initiated by

a momentary signal from the thermostat.

e. Dry contact night setback output for digital

night setback thermostats.

f. Ability to work with heat/cool (Y, W)

thermostats.

g. Ability to work with heat pump thermostats

using O or B reversing valve control.

h. Single grounded wire to initiate night set-

back or emergency shutdown.

i. Boilerless system control can switch auto-

matically to electric heat at low loop water

temperature.

j. Control board shall allow up to 3 units to be

operated from one thermostat without any

auxiliary controls.

k. A relay to operate an external damper. The

control to be such that the damper will not

open until 30 minutes after the unit comes

back from Unoccupied mode.

l. Fan speed selection at thermostat.

m. A relay to restart a central pump or control a

24-v motorized water valve.

4. PremierLink™ Controller:

This control will function with Carrier Comfort

Network® (CCN) and ComfortVIEW™ soft-

ware. It shall also be compatible with Com-

fortLink™ controllers. It shall be ASHRAE 62-

99 compliant and Internet ready. It shall accept

a CO

sensor in the conditioned space and be

demand control ventilation (DCV) ready. The

communication rate must be 38.4K or faster.

5. LONWORKS Interface System:

Units shall have all features listed above (either

Complete C or Deluxe D) and the control board

shall be supplied with a LONWORKS interface

board, which is LONMark certified. This will

permit all units to be daisy chained via a 2-wire

twisted pair shielded cable. The following points

must be available at a central or remote com-

puter location:

a. space temperature

b. leaving-water temperature

c. discharge-air temperature

d. command of space temperature set point

e. cooling status

f. heating status

g. low temperature sensor alarm

h. low pressure sensor alarm

i. high pressure switch alarm

j. condensate sensor alarm

k. high/low voltage alarm

l. fan "ON/AUTO" position of space

thermostat

m. unoccupied / occupied command

n. cooling command

o. heating command

p. fan "ON / AUTO" command

q. fault reset command

r. itemized fault code revealing reason for

specific shutdown fault (any one of 7)

This option also provides the upgraded 75 va

control transformer with load side short circuit

and overload protection via a built-in circuit

breaker.

H. Electrical:

1. A control box shall be located within the unit

compressor compartment and shall contain a

75 va transformer, 24-volt activated, 3-pole com-

pressor contactor, terminal block for thermostat

wiring and solid-state controller for complete unit

operation. Electro-mechanical operation WILL

NOT be accepted.

2. Units shall be nameplated for use with time-

delay fuses or HACR circuit breakers.

3. Unit controls shall be 24-volt and provide heat-

ing or cooling as required by the remote

thermostat.

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Carrier 50HQ User Manual Page 31

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