Diagnostic Flashcards
Achieve quicker connection between what your seeing and where you should look.
Callback
Customer had a furnace, A/c, Humidifier and EAC installed in june.
The first cold snap was yesterday, and now their thermostat is blank.
What would be a likely cause?
Humidifier solenoid was wired in parallel, causing it to short when burners and blower we’re running.
Callback
Customer just had a new Furnace installation yesterday.
This morning they have no hot water.
What could be the likely issue?
1.Pilot went out on a atmospheric water heater, when the installers hotswapped the furnace gas valve.
2.Water heater never got re-lit, before installers left.
On most, furnaces what will shut the unit down if the drain is backing up?
Pressure Switch attached to the collector box
What connection is required on a thermostat with no battery back up
“C”
Where does a thermostat send 24v when theirs a call for heat?
“W”
Where does a thermostat send 24v when theirs a call for cooling?
straight cool unit
“G” and “Y”
Where does a thermostat send power when theirs a call for the fan
“G”
Diagnostic
You go to a no heat, While filling out your form you notice the inducer starts but the igniter doesn’t glow, and the gas valve doesn’t open.
Where do you start your checks?
1.Pressure switch stuck open
2.Inducer may not be creating enough negative pressure(I.E Blocked Drain, Blocked terminations)
