Parts Encyclopedia · Updated 2026-07-16
HVAC Parts, Explained in Plain English
Every major part in a residential AC or heat pump — what it does, why Phoenix heat kills it specifically, the failure signs you can spot yourself, and what an honest repair looks like. No jargon, no invented internet prices.
Why we wrote a parts library for homeowners
When an air conditioner quits on a 110° afternoon, the diagnosis arrives as a part name — "it's the capacitor," "you need a control board," "the compressor is done" — and most homeowners have to take that word on faith. This library removes the faith requirement. Each guide explains what the part actually does (with one analogy that sticks), why the Sonoran Desert is uniquely hard on it, which symptoms it causes when it fails, and what an honest repair conversation sounds like.
One thing you will not find here: made-up part prices. Champion Air prices every repair the same way — an $89 diagnostic finds the actual failed part (waived when you proceed with the repair, $0 year-round for ChampionCare members), then a flat-rate quote in writing, naming the part, before any work starts. If another company already named a part and a price, our second opinion is free.
Not sure which part is your problem? Start from the symptom instead — the AC-not-cooling guide walks the triage in order, and each entry below links its matching symptom pages.
Capacitor
The stored electrical shove that starts your compressor and fans — and the Valley's most-replaced part.
Read the guideCompressor
The heart of the system: the pump that moves refrigerant and carries the whole cooling cycle.
Read the guideCondenser Coil
Your AC's radiator — the outdoor coil where the house's heat finally leaves for good.
Read the guideEvaporator Coil
The cold indoor coil where your air actually gets cooled — and where ice, dust, and leaks strike.
Read the guideBlower Motor
The fan that moves every cubic foot of cooled air through your ducts, summer and winter.
Read the guideContactor
The heavy-duty switch that powers the outdoor unit on and off — thousands of times a summer.
Read the guideReversing Valve
The one part that makes a heat pump a heat pump — it flips cooling into heating.
Read the guideCondensate Drain & Float Switch
The narrow pipe and little switch that keep gallons of daily condensate out of your ceiling.
Read the guideTXV / Expansion Valve
The metering valve that feeds refrigerant to the coil in exactly the right dose, moment to moment.
Read the guideControl Board
The circuit board that sequences everything — blower, safeties, and the call for cooling.
Read the guideTransformer
The small part that makes the 24-volt power your thermostat and controls run on.
Read the guideRefrigerant Line Set
The insulated copper pair connecting your system's two halves — efficiency and quiet live here.
Read the guideDisconnect & Breaker
The shutoff box and breaker that deliver and guard every amp your AC uses.
Read the guideKnow the part — or want us to find it?
The $89 diagnostic names the actual failed part, waived when you proceed with the repair — $0 for ChampionCare members. Flat-rate quote in writing before any work starts.