York P*UR Installation Instructions Manual

Contents

York P*UR Installation Instructions Manual Manual pdf 26 page image

035-17477-001 Rev. A (801)26 Unitary Products GroupAuxiliary Limit Controls: Downflow/horizontal units have asingle limit switch mounted on the blower assembly. This is amanual reset control and gives high temperature protection inthe event of a blower motor failure.START-UP AND ADJUSTMENTSThe initial start-up of the furnace requires the following addi-tional procedures:1. When the gas supply is initially connected to the furnace,the gas piping may be full of air. In order to purge this air,it is recommended that the ground union be looseneduntil the odor of gas is detected. When gas is detected,immediately retighten the union and check for leaks.Allow five minutes for any gas to dissipate before con-tinuing with the start-up procedure.2. The condensate trap must be filled with water before put-ting the furnace into operation. The recommended pro-cedure is as follows:a. Disconnect the condensate drain hose from theinduced draft blower discharge.b. Elevate this hose and fill with water using a funnel.c. Replace the condensate drain hose and clamps.NOTE: If this procedure is not followed, the unit may notproperly drain on initial start up.3. All electrical connections made in the field and in the fac-tory should be checked for proper tightness.IGNITION SYSTEM SEQUENCE1. Turn the gas supply ON at external valve and main gasvalve.2. Set the thermostat above room temperature to call forheat.3. System start-up will occur as follows:a. The induced draft blower motor will start and comeup to speed. Shortly after venter start-up, the hotsurface igniter will glow for about 17 seconds.b. After this warm up, the ignition module will energize(open) the main gas valve for seven seconds.c. After flame is established, the supply air blower willstart in about 30 seconds.NOTE: Burner ignition may not be satisfactory on first startupdue to residual air in the gas line or until gas manifold pres-sure is adjusted. The ignition control will make 3 attempts tolight before locking out.4. With furnace in operation, paint the pipe joints and valvegasket lines with a rich soap and water solution, Bubblesindicate a gas leak. Take appropriate steps to stop theleak. If the leak persists, replace the component.FIGURE 36 : Pressure Switch Tubing RoutingBe sure proper ventilation is available to dilute andcarry away any vented gas.UPFLOW1LPDOWNFLOW / HORIZONTALPerform the following procedures only after thecondensate trap has been properly piped to adrain connection using the procedure in thisinstruction.DO NOT omit this test! Never use a flame to checkfor gas leaks.