Bryant manual K.Electrical Requirements, 549B, 549C

GUIDE SPECIFICATIONS — 549B036-120, 549C024-060 (cont)

3.Compressor with standard controls shall be capable of operation down to –20 F (in heating mode) ambi- ent outdoor temperature.

4.Unit shall be capable of simultaneous heating duty and defrost cycle operation when using accessory electric heaters.

K.Electrical Requirements:

All unit power wiring shall enter unit cabinet at a single factory-predrilled location.

L.Motors:

1.Compressor motors shall be cooled by refrigerant gas passing through motor windings and shall have line break thermal and current overload protection.

2.Indoor-fan motor shall have permanently lubricated bearings and inherent automatic-reset thermal over- load protection.

3.Totally enclosed outdoor-fan motor shall have per- manently lubricated bearings, and inherent auto- matic-reset thermal overload protection.

M.Special Features:

Certain features are not applicable when the features designated * are specified. For assistance in amending the specifications, contact your local Bryant Sales Office.

1.Roof Curbs (Horizontal and Vertical):

a.Formed galvanized steel with wood nailer strip and shall be capable of supporting entire unit weight.

b.Permits installation and securing of ductwork to curb prior to mounting unit on the curb.

*2. Integrated Economizers:

a.Integrated integral modulating type capable of simultaneous economizer and compressor opera- tion. During economizer operation, up to two compressors on sizes 090-120 will operate.

b.Available as a factory-installed option in vertical supply/return configuration only. (Available as a field-installed accessory for dedicated horizontal and/or vertical supply return configurations.)

c.Includes all hardware and controls to provide cooling with outdoor air.

d.Equipped with low-leakage dampers, not to exceed 2% leakage at 1 in. wg pressure differential.

e.Capable of introducing up to 100% outdoor air.

f.EconoMi$erIV and EconoMi$er2 shall be equipped with a barometric relief damper capable of relieving up to 100% return air.

g.Designed to close damper(s) during loss-of- power situations with spring return built into motor.

h.Dry bulb outdoor-air temperature sensor shall be provided as standard. Outdoor air sensor set point is adjustable and shall range from 40 to 100 F. For the EconoMi$erIV, the return air sen- sor, indoor enthalpy sensor, and outdoor enthalpy sensor shall be provided as field-installed acces- sories to provide enthalpy control, differential enthalpy control, and differential dry bulb temper- ature control. For the EconoMi$er2, the enthalpy, differential temperature (adjustable), and differen- tial enthalpy control shall be provided as field- installed accessories.

i.The EconoMi$erIV and EconoMi$er2 shall have a gear-driven parallel blade design.

j.EconoMi$erIV microprocessor control shall pro- vide control of internal building pressure through its accessory power exhaust function. Factory set at 100%, with a range of 0% to 100%.

k.EconoMi$er2 shall be capable of control from a 4 to 20 mA signal through optional 4 to 20 mA design without microprocessor control (required for third party control interface).

l.EconoMi$erIV Microprocessor Occupied Mini- mum Damper Position Setting maintains the mini- mum airflow into the building during occupied period providing design ventilation rate for full occupancy (damper position during heating). A remote potentiometer may be used to override the set point.

m.EconoMi$erIV Microprocessor Unoccupied Mini- mum Damper Position Setting — The EconoMi$erIV damper shall be completely closed when the unit is in the occupied mode.

n.EconoMi$erIV Microprocessor IAQ/DCV Maxi- mum Damper Position Setting — Setting the maximum position of the damper prevents the introduction of large amounts of hot or cold air into the space. This position is intended to satisfy the base minimum ventilation rate.

o.EconoMi$erIV Microprocessor IAQ/DCV control modulates the outdoor-air damper to provide ventilation based on the optional 2 to 10 vdc CO2 sensor input.

p.Compressor lockout sensor (opens at 35 F, closes at 50 F).

q.Actuator shall be direct coupled to economizer gear, eliminating linkage arms and rods.

r.Control LEDs:

1)When the outdoor-air damper is capable of providing free cooling, the “Free Cool” LED shall illuminate.

2)The IAQ LED indicates when the module is on the DCV mode.

3)The EXH LED indicates when the exhaust fan contact is closed.

s.Remote Minimum Position Control — A field- installed accessory remote potentiometer shall allow the outdoor-air damper to be opened or closed beyond the minimum position in the occu- pied mode for modified ventilation.

3.Manual Outdoor-Air Damper:

Manual damper package shall consist of damper, birdscreen, and rainhood which can be preset to admit up to 50% outdoor air for year round ventilation.

*4. 100% Two-Position Damper:

a.Two-position damper package shall include single blade damper and motor. Admits up to 100% outdoor air.

b.Damper shall close upon indoor (evaporator) fan shutoff.

c.Designed to close damper during loss of power situations.

d.Equipped with 15% barometric relief damper.

549B, 549C

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