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GAS HEAT Types of Units & Maintenance

GAS HEAT Types of Units & Maintenance. Upflow – “Hiboy”– Stands vertically, top air discharge Low Boy – Used where there is little headroom Both supply and return are at the top Blower located behind the furnace Downflow- “Counterflow” – Stands vertically, bottom air discharge

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GAS HEAT Types of Units & Maintenance

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  1. GAS HEAT Types of Units & Maintenance

  2. Upflow – “Hiboy”– Stands vertically, top air discharge • Low Boy – Used where there is little headroom • Both supply and return are at the top • Blower located behind the furnace • Downflow- “Counterflow” – Stands vertically, bottom air discharge • Horizontal – Left or right discharge • Multipurpose – Multi-positional TYPES OF FURNACES

  3. Return Air Supply Air Floor THE UPFLOW FURNACE Heat Producing System Blower

  4. Return Air Supply Air Floor Blower THE LOWBOY FURNACE Heat Producing System

  5. Return Air THE DOWNFLOW FURNACE Supply Air Floor

  6. Return Air Supply Air Floor THE HORIZONTAL FURNACE INSTALLED IN A BASEMENT

  7. LOW EFF UNITS ONLY MAKE ONE PASS THROUGH THE HEAT EXCHANGER

  8. MEDIUM EFF UNITS MAKE TWO OR MORE PASSES THROUGH THE HEAT EXCHANGER, CAPTURING MORE HEAT FROM THE EXHAUST

  9. A.K.A. 90+ 0R CONDENSING FURNACES • Efficiency increased by keeping excessive heat from being vented to the atmosphere • Have two heat exchangers, both with multiple passes. • Range from 87% to 97% AFUE ratings • The additional drop in exhaust temp causes condensation to form, the second heat exchanger and all related parts are either stainless steel or plastic. HIGH EFFICIENCY GAS FURNACES

  10. Two-stage gas valves and combustion blowers • First stage provides 50% to 70% of heating output • First stage gas pressure is 1.75 in. W.C. • Second stage provides 100% of total heating output • Second stage gas pressure is 3.5 in. W.C. • Two pressure switches to prove flame • Low pressure switch for low blower speed • High pressure switch for high blower speed • Provide better control of space temperature TWO-STAGE FURNACES

  11. MODULATING FURNACES • Follows the heat loss of the structure • Discharge air temperature is modulated for even heating of the structure • Adjusts to changes in gas heating values and air density • Determines exact heating requirements for the space • Optimizes furnace efficiency and performance • Utilize variable speed blowers

  12. ANNUAL MAINTENANCE • FIRST- ALWAYS BE SURE THAT THE GAS & ELECTRICITY ARE OFF!! • CHECK WITH CUSTOMER TO SEE IF THEY HAVE ANY COMPLAINTS • RUN THE UNIT AND MAKE SURE IT WORKS AND LIGHTS SMOOTH

  13. CHECK AIR FILTER & BLOWER • CLEAN BURNERS • CHECK PILOT ASSEMBLY • CHECK THERMOCOUPLE • CHECK/CLEAN HEAT EXCHANGER FOR SOOT, FATIGUE, ROT & CRACKS • CHECK/CLEAN FLUE PIPE & CHIMNEY

  14. CHECK THE SPARK TO PILOT OR HSI IGNITION SYSTEM IF IT HAS ONE OF THESE TYPES INSTEAD OF STANDING PILOT • CHECK THE CONDENSATE DRAIN AND PUMP IF APPLICABLE • CHECK THE FLAME ROD SIGNAL WHEN TESTING THE UNIT

  15. TO CHECK THE DC SIGNAL YOU PUT YOUR METER IN SERIES WITH THE SENSOR, SET TO DC MILLIAMPS. • WITH THE UNIT RUNNING AND SENSOR IN THE FLAME YOU SHOULD GET A READING OF AT LEAST 1.5 DCMA AND IT IS USUALLY LESS THAN 10.

  16. CHECK PRESSURES, ADJUST IF NECCESARY • CHECK SAFETY, CONTROLLER OPERATION, IGNITION, HSI, SPARK • CHECK FLAME FOR COLOR, IMPINGEMENT AND STABILITY • PERFORM THE EFFICIENCY TEST AND RECORD RESULTS AND ANY REPAIRS THAT ARE REQUIRED OR RECOMMENDED

  17. THE ACCEPTABLE LEVEL OF CO EXHAUSTING OUT OF OUR EQUIPMENT IS 200PPM OR LESS • IF YOU HAVE A CO TESTER USE IT AND RECORD THE RESULTS SO YOU AND YOUR COMPANY HAVE A RECORD

  18. Incomplete combustion produces carbon monoxide • Correct air adjustments are essential • CO2 levels aid in secondary air adjustments • CO2 level increases as secondary air decreases • CO2 level for natural gas is 11.7% to 12.2% • CO2 of 14% for butane and 13.7% for propane • Correct flame should be blue with orange tips • Yellow flame indicates the production of carbon monoxide COMBUSTION EFFICIENCY

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