
1.) Thermostat – Check that anticipator and ensure it is properly set. Adjust if needed. If possible, also check or calibrate temperature readings.
2.) Air Filter – Inspect air filter. Look for debris that could be restricting airflow in return. Try to inspect the face of indoor coil.
3.) Blower Motor – Check motor amperage and compare it to motor ratings. If needed, oil motor. Check to ensure of proper motor speed.
4.) Run Capacitor – Check micro farads. Recommend replacement if it is not within 10%. Check for oil leaks or voltage drop. Replace if leaking or bad.
5.) Heat Anticipator – Ensure thermostat is properly set. If not, set anticipator to proper amperage. Wrong settings = short cycling.
6.) Thermocouple - Ensure the thermocouple is in its proper position. Look for signs of deterioration or crystals that may be starting to develop.
7.) Burners – Check for a solid blue flame. If orange or yellow flame appears look for cracked heat exchanger, dirty burners, or poor exhaust flow.
8.) Heat Exchanger – Examine heat exchanger for cracks or signs of stress or fatigue. Shut down unit if you suspect that there may be a problem.
9.) Gas Lines - Inspect all gas lines for possible leaks. Use soap and bubbles and check commonly known areas where leaks often do occur.
10.) Temperature Rise – Determine change on temp. between supply and return air. Check this with the allowable rise listed on the units rating plate.
11.) Safety Controls – Check door safety switch and sequence of safety operations. Also check on all other auxiliary safety devices.
12.) Indoor Coil – Check indoor coil to make sure it is not restricting air flow. Check for possible leaks that may decrease systems performance.
13.) Drafting – Ensure of proper flame. Look for signs of rust or blockage. If signs exist, look to see if the flue needs to be cleaned or replaced.
14.) Limit Switches & Fan Control – Check fan control for proper cut-in and cut-out. Disconnect the power to blower and test upper limit switch.
15.) Pilot / Ignition System – Check for flame quality and roll out. Look for hard ignition or any signs of delayed ignition. Check warm up time.
16.) Ductwork – Check both the supply and return air ducts cleanliness. If in attic, check to see if any air ducts have collapsed or separated.
17.) Heat Strips – Check sequencers, fan control, safety controls, limit switches, and element connections. Check amperages throughout.
18.) Crank Case Heater – Use AMP probe to ensure the crank case heater is functioning. If it is not, oil may foam and reduce compressor viscosity.
19.) Defrost Controls – Try to send unit into defrost to check its function. Inform occupants of what they can expect during defrost.
20.) Split Temperature – Take split temp to measure efficiency. Poor split temps indicate bad strips, dirty filter, or blocked coil.