MEMORANDUM TO: Holders of Contracts Documents FROM: Karen ...

27.17 Protective grommets shall be provided at points where refrigeration hoses, heater hoses,
condensate hoses, and electrical harnesses (wires) penetrate metal or other materials.
27.18 All HVAC system hoses and harnesses (wires) that pass within twelve (12) inches of the exhaust
system shall be shielded in a manner to prevent heat damage.
27.19 The air conditioning system shall utilize environmentally friendly R-134A refrigerant. Compressor
manufacturers specified refrigerant oil shall be utilized.
27.20 Performance
27.20.1 The air conditioning system shall be able to reduce the vehicle interior temperature from ninety
five (95) degrees Fahrenheit to seventy five (75) degrees Fahrenheit within thirty (30) minutes when the
ambient temperature outside the vehicle is maintained at ninety five (95) degrees Fahrenheit for at least
four (4) hours.
27.20.2 The performance standards shall be met in test conditions with vehicle engine operating
between 1,000 and 1,500 RPM’s.
27.20.3 HVAC system shall include a heat unit for the passenger area. This unit shall be mounted on the
floor of the vehicle and shall have a minimum rating of 60,000 btu/hr. All heater coils shall be heavy
duty copper or aluminum. Heavy duty quarter turn shut off valves shall be located in the supply and
return lines to the passenger area heater. These valves shall be readily accessible. All heat controls shall
be located at the drivers control panel.
27.21 For Vehicles on a 138 inch nominal wheelbase:
27.21.1 A/C system shall be American Cooling Technology (A.C.T.) Model ACT-40 HD, Trans/Air Model
TA-712 Super, Carrier or MTA prior approved equal.
27.21.2 For wheelbase of 138 inch nominal, the system shall utilize two (2) engine driven compressors.
One (1) is the OEM supplied compressor driven off the vehicle engine which is specific to the OEM indash
driver’s area air conditioning system. The second add-on compressor is for the passenger area air
conditioning system. This compressor is driven off the vehicle engine and is nominal ten (10) cubic inch
displacement and is protected by high and low pressure switches.
27.21.3 A/C system shall include a rear ceiling mounted evaporator rated at a minimum output of
45,000 BTU and 800 CFM at ambient conditions of 95 degrees Fahrenheit and 40% relative humidity.
The system shall operate independently of the front chassis supplied system.
27.21.4 Evaporator shall be a single slim line unit, A.C.T., Trans/Air, Carrier or MTA approved equal,
mounted to the roof frame structure in the top rear of the vehicle in a location that does not interfere
with passengers or wheelchair occupants.
27.21.5 Evaporator shall be copper tube, aluminum fin coil or MTA approved equal with expansion
valve, low-pressure switch, and concealed drain hoses. The drain hoses shall be protected at points
where the hose penetrates metal or other material.
27.21.6 Evaporator shall incorporate a 12 volt DC motor with total minimum airflow of 800 CFM.
27.21.7 Evaporator cover shall be constructed of fire retardant material, which conforms to FMVSS 302.
27.21.8 System shall utilize an ACT, Trans/Air, Carrier, or the MTA approved equal, skirt mounted 2-fan
condenser, rated at a minimum 60,000 BTU, located on the street side of the vehicle, in front of the rear
wheels, and installed to minimize collection of road dirt and facilitate maintenance.
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