Heating Systems
Three types of ignitors for a boiler/furnace are...
standing pilot, spark, & hot surface ignitor
How do you check if a double pole contactor is good on a condenser unit?
Check resistance of the coil on the contactor
What are the two type of motors a residential air handler have?
ECM (Electronically Commutated Motor) & PSC (Permanent Split Capacitor Motor)
How do you measure superheat?
Line Temperature (-) Gauge Saturated Temperature
What is the main electromagnetic device in a heat pump system?
Reversing Valve
What safety device does a Oil Furnace/Burner have to confirm ignition?
Cad Cell
True or False: A 3 Phase motor does not need a capacitor.
TRUE
True or False: Sensible heat is when the evaporator makes condensation.
FALSE: Latent Heat! Latent heat of evaporation (or vaporization) is the significant amount of energy (heat) needed to change a substance from a liquid to a gas (vapor) at a constant temperature,
How do you change the fan speed on a PSC motor?
Change the leads on the board
Two main types of heat pumps are?
Air to Air & Water source to air
What is the most common reason for the roll out switch to be tripping the system?
cracked HEX
R-24v, Y-Cool, W-Heat, G-Fan, C-Common
How many BTU's is considered 1 ton?
12,000BTU's
List three reasons a evaporator coil would freeze up.
True or False: On a heat pump system the compressor changes the direction of the refrigerant to switch from heating or cooling mode.
FALSE
Name three types of drafts on a combustible system.
Natural, negative(induced), & positive.
How do you check the windings of a single phase compressor? Name 3 windings? Which one will be the larger reading?
Check Resistance from Start-Common-Run.
Start-Run will have the largest reading
What unit is static pressure measured in?
Inches of Water Column. (W.C.)
Explain how does a TXV monitors superheat?
A TXV monitors superheat using a sensing bulb and capillary tube at the evaporator outlet; the bulb's refrigerant boils and creates pressure, pushing the valve open to allow more flow for high superheat, while lower superheat reduces bulb pressure, allowing the valve to close or restrict flow, always balancing forces to maintain a set superheat to protect the compressor.
Explain how a Heat pump deals with excessive refrigerant when operating.
A heat pump accumulator is a protective tank on the suction line, just before the compressor, designed to hold liquid refrigerant and oil temporarily, ensuring only vapor enters the compressor to prevent severe damage, especially crucial in heat pumps due to defrost cycles that cause refrigerant surges.
1. tstat calls for heat, Inducer motor, Air Pressure switch, Ignitor, gas valve, Flame sensor, blower motor.
How do you wire a dual run capacitor? How do you check if a dual run capacitor is good?
Check microfarads from C-H&C-F
Draw on the board contactor- capacitor wiring-
---
What is a reason my low side PSI will drop significant when running my air conditioner?
faulty TXV, Clogged filter drier
R-24v, Y-Compressor, G-Fan, O-Reversing Valve, W-Auxiliary heat, C-Common