York DM090 Installation Manual

Also see for PREDATOR DM 090: Installation manual Technical guide Installation manual Technical guide Installation instruction

Contents

127408-YIM-B-0606Unitary Products Group 45START-UP (COOLING)PRESTART CHECK LISTAfter installation has been completed:1. Check the electrical supply voltage being supplied. Besure that it is the same as listed on the unit nameplate.2. Set the room thermostat to the off position.3. Turn unit electrical power on.4. Set the room thermostat fan switch to on.5. Check indoor blower rotation.• If blower rotation is in the wrong direction. Refer toPhasing Section in general information section.• Check blower drive belt tension.6. Check the unit supply air (CFM).7. Measure evaporator fan motor's amp draw.8. Set the room thermostat fan switch to off.9. Turn unit electrical power off.OPERATING INSTRUCTIONS1. Turn unit electrical power on.NOTE: Prior to each cooling season, the crankcase heatersmust be energized at least 10 hours before the sys-tem is put into operation.2. Set the room thermostat setting to lower than the roomtemperature.3. First stage compressors will energize after the built-intime delay (five minutes).4. The second stage of the thermostat will energize secondstage compressor if needed.POST START CHECK LIST1. Verify proper system pressures for both circuits.2. Measure the temperature drop across the evaporatorcoil.START-UP (GAS HEAT)PRE-START CHECK LISTComplete the following checks before starting the unit.1. Check the type of gas being supplied. Be sure that it isthe same as listed on the unit nameplate.2. Make sure that the vent outlet and combustion air inletare free of any debris or obstruction.OPERATING INSTRUCTIONSLIGHTING THE MAIN BURNERS1. Turn “OFF” electric power to unit.2. Turn room thermostat to lowest setting.3. Turn gas valve counter-clockwise to “ON” position (see 19).4. Turn “ON” electric power to unit.5. If thermostat set temperature is above room tempera-ture, the main burners will ignite. If a second stage ofheat is called for, the main burners for second stage heatwill ignite for the second stage heat.POST START CHECKLISTAfter the entire control circuit has been energized and theheating section is operating, make the following checks:1. Check for gas leaks in the unit piping as well as the sup-ply piping.2. Check for correct manifold gas pressures. (See ’CHECK-ING GAS INPUT’.)3. Check the supply gas pressure. It must be within the lim-its shown on the rating nameplate. Supply pressureshould be checked with all gas appliances in the buildingat full fire. At no time should the standby gas pressureexceed 13 in. or the operating pressure drop below 5.0 infor natural gas units. If gas pressure is outside theselimits, contact the local gas utility or propane supplier forcorrective action.SHUT DOWN1. Set the thermostat to the lowest temperature setting.2. Turn “OFF” all electric power to unit.This furnace is equipped with an automatic re-ignitionsystem. DO NOT attempt to manually light the pilot.FIRE OR EXPLOSION HAZARDFailure to follow the safety warning exactly couldresult in serious injury, death or property damage.Never test for gas leaks with an open flame. Use acommercially available soap solution made specifi-cally for the detection of leaks to check all connec-tions. A fire or explosion may result causing propertydamage, personal injury or loss of life.