York ZT078-102 Installation Manual

Also see for ZT SERIES: Technical guide

6021980-UIM-A-1120Johnson Controls Ducted Systems 692. After you determine the temperature rise, calculate theCFM according to the following formula.3. Increase the blower CFM to decrease the temperature rise.Decrease the blower CFM to increase the rise (see Supplyair drive adjustment on page 58).Note: Each gas heat exchanger size has a minimumallowable CFM. Below this CFM, the limit opens.Inspecting and servicing burners and orifices1. Open the union fitting just upstream of the unit gas valveand downstream from the main manual shut-off valve inthe gas supply line.2. Remove the screws that hold each end of the manifold tothe manifold supports.3. Disconnect the wiring to the gas valves and spark igniters.4. Remove the manifold and gas valve assembly. Inspect theorifices and replace them if required.5. To service the burners, remove the heat shield on top ofthe manifold supports. Inspect the burners and replacethem if required.6. Reverse the above procedure to replace the assemblies.Verify that burners are level and seated at the rear of thegas orifice.Figure 31: Typical flameFigure 32: Typical two stage gas valveNavigation components for the SmartEquipment™ control boardThe following components are needed to access the controlpoints in the Smart Equipment™ control. Installation andoperation guides are available from your equipment dealer ordistributor.1. Local LCD on the unit control board.2. Mobile Access Portal (MAP) Gateway (portable).• Source 1 P/N S1-JC-MAP1810-OP3. MAP Gateway Quick Start Guide P/N 24-10737-164. MAP Gateway Instruction P/N 24-10737-8For more information on the Smart Equipment™ unit control boardnavigation, refer to the Smart Equipment™ Quick Start Guide.Note: For more in-depth sequence of operation of the SmartEquipment™ control, refer to the Smart Equipment™Controls Sequence of Operation Overview LIT-12011950.Before you check or change burners, pilot, or orifices,close the main manuals shut-off valve and turn off allelectrical power to the unit.HEAT EXCHANGER TUBEBURNER FLAME(BLUE ONLY)IGNITORBURNER BRACKETBURNERGASSUPPLYPIPEINLETPRESSURETAPHIGH & LOW GAS ADJUSTMENTOUTLETPRESSURETAPHI LOONOFFMATE-N-LOCKCONNECTORSMVCHIREGULATOR COVER SCREWS(REG. ADJ. BENEATH THESESCREWS)TERMINAL – HI (2ND STAGE)ON/OFF SWITCHCMPOUTLET PRESSURE TAPINLET PRESSURE TAPORTERMINAL – MP (1ST STAGE)TERMINAL – C (COMMON)