B8142 replace HVAC split system

Added: May 03, 2016 3:43 pm Modified: Jul 26, 2016 1:59 pmTrack Changes Detailed Description. Replace the existing DX air-cooled split system that serves the storage area of

Elec/Comm Sys Integ. Lab with floor plan dimensions about 60ft x 16.5ft and ceiling height 12.5ft. New

Replace HVAC Split System

SPECIFICATIONS AND CONDITIONS

indoor unit shall be overhung underneath the wood deck and above stock shelves. New disconnect of the

new outdoor DX air-cooled condenser shall be installed on exterior surface of the wall at the same

location as before. New indoor disconnect shall be mounted to the same location of the previous one and

hooked up to the new indoor air handler. Hook up existing condensate drain pipe to the new, indoor,

overhung air handler. Run new refrigerant line from indoor unit to outdoor unit thru the existing

penetration on the wall.

Hook up existing thermostat to the new split system for space temperature

control.

Indoor temperature set-points of occupied mode shall be 78oF for cooling mode and 68oF for heating

mode. For unoccupied mode, temperature set-point shall be reset 85oF for cooling and 55oF for heating.

2.1. *Contractor will coordinate with the PW POC prior to commencement of work to ensure all

scheduling and access issues have been worked out properly. Any questions will be directed to the

PW POC and not through the customer.

2.1.1. Demolition

2.1.1.1. Electrical

Demolish the outdoor wall-mounted disconnect and indoor, overhung disconnect and

wiring to the existing outdoor DX condenser and indoor air handler.

Existing indoor

thermostat shall remain in place.

2.1.1.2. Mechanical

Demolish the existing split system that serves the storage of Elec/Comm Sys Integ. Lab

including outdoor DX air-cooled condenser, an indoor air handler that was overhung

underneath the wood deck and above stock shelves, and refrigerant lines. Existing supply

ductwork shall remain in place.

2.1.2. Install

Install a new complete usable split DX system that serves the storage area under new

design conditions specified above.

2.1.2.1. Electrical

Install new NEC disconnect for the new outdoor unit on the exterior wall at the same

location as before. Install new NEC disconnect for the new indoor air handler. Hook up

power to new outdoor DX air-cooled condenser and new indoor air handler.

All wiring

shall comply with local and national code. Wire the existing thermostat to the indoor unit

and the outdoor unit. Thermostat shall be mounted on the partition wall of the two

storages. Provide outdoor thermostat and wiring to outdoor unit if required. New

equipment shall be 230V, 3phase, and 60Hz. Make sure power available adequate to feed

new equipment.

2.1.2.2. Mechanical

Install new complete usable brand-new split system that comprises of an outdoor DX aircooled

condenser and an indoor overhung air handling unit that shall be mounted

underneath wood deck and above stock shelves. Outdoor unit can be a DX air-cooled

condenser to provide cooling only in combination with indoor unit that has electric heater

to provide electric heating.

Outdoor unit can be a DX air-cooled heat pump condenser in

combination with indoor unit that has an electric heater to provide supplement heating.

Heating capacity of heat pump drops when outdoor temperature drops. When indoor

Replace HVAC Split System



heating demand rises, electric supplement heating is necessary. Two-stage heating is

preferred for electric heater for better temperature control. Mount new outdoor DX aircooled

condenser on the existing concrete slab. Be sure to provide enough clearance

around the condenser according manufacturer installation instruction when installing the

outdoor DX air-cooled condenser. Install new refrigerant lines (liquid line and vapor line)

from indoor unit to outdoor unit.

Liquid line shall have filter dryer and moisture indicator

sight glass. Vapor line shall be insulated per manufacturer instruction. New indoor unit

shall have prefilter with filtering efficiency MERV-8 or higher. Hook up new indoor air

handler to existing supply ductwork. Clean ductwork before installing AHU to it. Provide

transition duct if necessary. All new ductwork added to this job shall be galvanized steel

reinforced per SMACNA. New HVAC equipment shall be energy star certified. The

cooling and heating capacity of the new HVAC equipment shall be comparable to that of

the existing: 5 ton for cooling and 65MBH for heating. See referenced information of the

existing equipment in 2.1.2.4.

2.1.2.3.

Submittals

Provide submittal for HVAC split system including an outdoor DX air-cooled condenser

on slab and an indoor air handling unit including electrical information, disconnects, and

outdoor thermostat if required. The new DX split system shall provide adequate cooling

and heating capacity to the space. Make sure power supply to the new system matches

with existing units’ requirements.

2.1.2.4. Referenced Information:

Existing Outdoor Unit:

Make: Carrier

Model: 38BQ006410

Serial: P03004

Cooling Capacity: 58,000Btuh

Heating Capacity: 65,000Btuh

Existing Indoor Unit:

Make: Carrier

Model: 28HQ060000

Serial: N041373

Refrigerant: R22

Cooling Capacity: 60,000Btuh

Notes: Refrigerant R-22 won’t be allowed to use in this job.

Information above shall be field verified by contractor for accuracy.

Verify existing feed power available adequate for new equipment.