Install guides
Every HVAC install, step by step
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Whole-system installs
Split-System AC / Heat Pump InstallChecklistWhole-job check-off: pre-job, set equipment, line set, electrical, evac, charge, commission.26 stepsLockedInstall Ductwork, Plenums & TransitionsGuideBuild and attach supply/return plenums and transitions, seal every joint with UL181 mastic (not tape alone), support runs so flex doesn't sag, insulate ducts in unconditioned space to R-8, size to the design CFM, and keep the return fully sealed (no panned building cavities).6 stepsLockedReplace a Zone DamperGuideReplace a motorized zone damper: identify the type (power-open/power-close vs spring-return / power-open–spring-close), match the duct size and shape (round vs rectangular), transfer the end switch + zone-panel wiring, set the blade to the ducting, then verify it drives fully open and fully closed when its zone calls.5 stepsLockedReplace a Zone Control PanelGuideReplace a zoning panel/board: land each zone thermostat and damper, the transformer, and the changeover / leaving-air (discharge) sensor; set the dip switches (system type, stages, fan, purge/timers); then verify each zone calls the right mode and the bypass/dump damper bleeds excess static when only a small zone is open.6 stepsLockedInstall an HRV / ERV (Balanced Ventilation)GuideInstall a balanced-ventilation HRV or ERV (HRV moves heat only; ERV also transfers moisture — pick per climate): duct the stale-exhaust and fresh-supply runs, BALANCE the two airflows to equal CFM, drain the condensate on an HRV, interlock/control it with the air handler, then verify the cross-flow core and the defrost cycle.6 stepsLocked
Condenser
Set the Condensing UnitGuidePad, level, clearances, hold-downs, disconnect, and whip — set it right so it drains and breathes.5 stepsLockedReplace a Compressor (Condenser)GuideRecover first, lock out + megohm/ohm the windings to confirm a good vs burned-out compressor, cut it out (don't unbraze a pressurized system), braze the new one in with flowing N2, add a suction-line drier after any burnout + a new liquid-line drier, deep-evacuate ≤500 microns, and weigh in the nameplate charge.11 stepsLockedReplace a Condenser CoilGuideRecover, unbolt/unbraze the microchannel or tube-and-fin coil (handle microchannel carefully — it's easy to damage and often not field-repairable), braze the new coil in with N2, install fresh driers, pressure-test + deep-evacuate, recharge, and straighten/protect the fins.8 stepsLockedReplace a Condenser Fan MotorGuideMatch HP, RPM, rotation (CW/CCW from the shaft end), voltage, frame and shaft diameter + mounting; match the run-cap µF; set the blade depth in the orifice and the correct blade pitch/direction; wire per the diagram; then verify rotation and amp draw against the FLA.7 stepsLockedReplace a Contactor (Condenser)GuideDe-energize and verify 0 V, match the pole count (1 vs 2), the 24 V coil voltage, and the FLA/resistive amp rating, photo the wiring, land line/load (T1–T2) + the 24 V coil leads, check for pitted/welded contacts as the failure cause, then verify pull-in and the voltage drop across the contacts.6 stepsLockedInstall a Hard-Start Kit (Condenser)GuideA potential-relay + start-capacitor kit for a single-phase compressor that hard-starts (long line sets, low starting voltage, marginal start). It is NOT a cure for a failing compressor. Wire the start cap through the potential relay correctly, then verify it starts and that the relay drops the start cap out of the circuit.6 stepsLockedReplace a Crankcase Heater (Compressor)GuideReplace a compressor crankcase heater (belly-band wrap or insertion-well type) that keeps the oil warm and drives refrigerant out of the crankcase to prevent migration / flooded starts (especially heat pumps and low-ambient cooling). Match the type/voltage/wattage, note whether it's always-on or contactor-controlled, energize it BEFORE restarting after a cold soak, and verify it actually warms.5 stepsLockedReplace a Service Valve (Condenser)GuideReplace a leaking/stripped service (ball/king) valve at the condensing unit: recover the charge, braze the new valve in with flowing nitrogen while heat-sinking the valve body, install a new liquid-line drier, nitrogen pressure-test, deep-evacuate, recharge, and verify both the Schrader core port and the valve seat hold.6 stepsLockedInstall a Low-Ambient Control (Condenser)GuideInstall a low-ambient control so the unit can cool in cold weather: either a fan-cycling pressure switch or a head-pressure (variable fan-speed) control / condenser-flooding valve. Set the cut-in/cut-out (or modulation band) to hold head pressure up, then verify the condenser fan cycles/modulates to keep liquid pressure where the metering device can still feed the evaporator.5 stepsLockedReplace a Condenser Fan BladeGuideReplace just the condenser fan blade (motor stays): match diameter, pitch, blade count, rotation, and bore; set the blade depth in the orifice/shroud (typically about 1/2 to 2/3 of the blade inside the shroud); tighten the set screw on the shaft flat; then confirm it runs balanced and pulls the right amps.6 stepsLocked
Air handler / coil
Install the Air Handler / CoilGuideMount level, build the drain + P-trap + float switch, and seal the plenum transitions.7 stepsLockedInstall the Condensate DrainGuideSlope the line, set a correct-depth P-trap for the draw-through coil, add primary + secondary drainage and a float switch wired to cut cooling, then flush and test.5 stepsLockedInstall an Electric Heat Kit (Strip Heat)GuideMatch the kit kW to the air handler and the electrical service (may need a second circuit), land it per the wiring diagram so sequencers stagger the elements, size the breaker/wire, verify airflow first, then check per-element amp draw and temperature rise.8 stepsLockedReplace an Evaporator Coil (Air Handler)GuideRecover, cut the old coil out, set the matched cased/uncased coil with the correct TXV or fixed orifice/piston + a new filter drier, braze with N2, nitrogen pressure-test, deep-evacuate, recharge and verify superheat/subcool, then rebuild the condensate pan/P-trap + secondary and seal the cabinet.10 stepsLockedReplace an ECM Blower Motor (Air Handler)GuideECM and PSC motors are NOT interchangeable — decide module-only vs full motor, match the program/model (a constant-CFM ECM must be programmed/matched to the unit), transfer the CFM tap/dip-switch airflow settings, handle the 5-pin power + 16-pin control connectors carefully, bench-test if needed, then verify CFM and static after.8 stepsLockedReplace an Electric Heat Sequencer (Air Handler)GuideConfirm the sequencer is the fault, match the contact count and timing, install it, and verify each element bank energizes in staggered sequence (so inrush is limited, not all banks at once) with amp draw on-spec.6 stepsLockedReplace a PSC Blower Motor (Air Handler)GuideMatch HP, speed count, voltage, rotation, and frame plus the run-capacitor µF; land the multi-speed TAPS correctly (identify which tap is the heat speed vs the cool speed); then verify rotation, CFM/external static, and amp draw against the nameplate.6 stepsLockedReplace a Blower Wheel (Air Handler)GuideSwap the squirrel-cage wheel: set screw on the FLAT of the shaft, correct wheel orientation/rotation, center the wheel in the housing with the proper inlet gap, balance and clean it, then verify CFM/external static and amp draw.6 stepsLockedInstall a UV-C Air/Coil Sterilization LightGuideInstall an IAQ UV-C lamp to irradiate the evaporator coil/drain pan (coil-sterilization) or the airstream. UV-C is an eye/skin hazard — NEVER look at it lit and install the kit's door interlock/safety. Mount to hit the target, tap power safely, keep UV off nearby flex/wiring/plastics, and note the annual bulb replacement.6 stepsLockedInstall a Media Air Cleaner CabinetGuideInstall a high-MERV media filter cabinet on the return: size it to the unit's CFM so the deep-pleated media doesn't choke airflow, mind the ADDED static pressure (don't starve the blower — re-check total external static after), seal the cabinet so air can't bypass the media, then set the airflow/return and confirm the system still breathes.6 stepsLockedInstall a Bypass HumidifierGuideInstall a whole-house bypass (or powered) humidifier: mount it on the supply or return plenum and run the bypass duct to the opposite plenum so warm air flows through it, tap the water supply (saddle valve / line) and route the drain, wire the humidistat into the blower / 24V so it runs only on heat-with-airflow, set the water panel, and verify water flow + evaporation.6 stepsLocked
Furnace
Install a Gas FurnaceGuideSet with clearances, vent per category (never mix), size + drip-leg the gas line and leak-check, set manifold pressure, then verify temperature rise and run a CO/combustion test.9 stepsLockedReplace a Furnace Control Board (IFC)GuideReplace the integrated furnace control: photograph + label every wire first, match the OEM board/firmware, transfer the dip-switch/jumper settings (blower-off delay, etc.), land line + 24 V + the limits/flame leads, then verify the full sequence of operations and the flame signal.7 stepsLockedReplace a Gas Valve (Furnace)GuideShut off + lock the gas and relieve pressure, match the valve (NG vs LP, redundant/combination, inlet size), use approved gas-rated thread sealant (skip the first two threads), leak-check with bubbles or an electronic detector — never a flame — then reset/verify manifold pressure under a call and confirm ignition + a clean flame.7 stepsLockedReplace a Hot Surface Igniter (Furnace)GuideMatch the OEM igniter and voltage type (120 V silicon-carbide vs newer line/low-voltage silicon-nitride), handle the element by its ceramic base ONLY (oil + bumps crack carbide), set the gap/position per spec, verify cold resistance (SiC ~40–90 Ω), then confirm it glows and lights the burners.7 stepsLockedClean or Replace a Flame Sensor (Furnace)GuideDecide clean-vs-replace, make sure the rod sits IN the flame, lightly clean it (don't grind/sand the rod down), and verify the microamp flame-rectification signal in µA series — typically ~2–6 µA, with lockout below ~0.5–1 µA.6 stepsLockedReplace a Draft Inducer Motor (Furnace)GuideConfirm the inducer is the fault, swap it with a NEW gasket, clear the pressure-switch port and sensing tubing while you're in there, then verify the pressure switch closes on inducer start, the wheel spins free, and amp draw is on-spec.6 stepsLockedReplace a Pressure Switch (Furnace)GuideFind the real cause first — a blocked sensing port, plugged condensate trap, or restricted vent is more common than a failed switch — then match the setpoint ("WC) and the normally-open config, install, and verify it closes on inducer start. Never jumper a pressure switch to run the furnace.5 stepsLockedReplace a High-Limit / Rollout Switch (Furnace)GuideA tripped manual-reset ROLLOUT switch signals a real problem — cracked heat exchanger, blocked flue, or bad combustion — so diagnose and fix the CAUSE, don't just reset/replace. The auto-reset HIGH-LIMIT protects on low airflow. Match the temp rating and verify the trip plus correct airflow.5 stepsLockedService the Gas Burners (Furnace)GuidePull and clean the burners plus the crossover/carryover ports, check burner alignment and a crisp blue flame (lazy/yellow flame = a problem), clear scale and spider/insect nests, reseat with no gas leaks, then verify ignition, carryover, and flame sense.6 stepsLockedReplace a Heat Exchanger (Furnace)GuideConfirm the crack first (visual/mirror, CO in the supply, or a combustion analyzer), weigh the repair-vs-replace economics, then fully tear the furnace down (gas, electrical, venting, burners, blower), swap the matched heat exchanger, reassemble to spec, and run a MANDATORY combustion/CO test + draft check before it goes back in service.9 stepsLockedReplace an Ignition Control Module (DSI / Intermittent Spark)GuideReplace an older direct-spark (DSI) or intermittent-pilot ignition module (distinct from the integrated IFC board): match the OEM module + ignition sequence, transfer wiring, set the spark/electrode gap, then verify flame rectification (microamp sense), trial-for-ignition timing, and that it locks out and re-tries correctly on a failed light.6 stepsLockedReplace a Thermocouple (Standing Pilot)GuideReplace the thermocouple on a standing-pilot system: the tip sits IN the pilot flame and makes a small DC millivolt signal (healthy ~25–30 mV open-circuit; the gas-valve magnet drops out when it falls too low). Mount finger-tight plus about a quarter turn (do NOT overtighten), position the tip in the flame, and verify the pilot stays lit after you release the valve knob.6 stepsLockedReplace a Pilot Assembly (Standing Pilot)GuideReplace the standing-pilot burner assembly: the pilot orifice + bracket that shapes and aims the flame at the thermocouple/flame sensor. Match and clear the orifice, transfer the thermocouple/sensor, set the flame so it fully envelops the sensing tip, then light and verify the pilot holds and the main burner ignites.6 stepsLocked
Heat pump
Install a Heat-Pump Outdoor UnitGuideSet on risers/a stand above snow with room for defrost meltwater to drain, level on a pad with clearances, run the line set, then verify reversing-valve (O/B) operation, defrost, and configure auxiliary heat + balance point.9 stepsLockedReplace a Reversing Valve (Heat Pump)GuideRecover, then braze the new 4-way valve in WITHOUT cooking the body — wrap it in a wet rag / heat-sink compound and keep the flame moving so the slide doesn't warp; orient it correctly (suction to the common tube, solenoid on the correct side), braze all 4 stubs with N2, fit the solenoid coil in its de-energized (cooling) default, new driers, evac, recharge, and verify it shifts on a call for heat.10 stepsLockedReplace a Defrost Control Board (Heat Pump)GuideMatch the OEM board, set the defrost interval pins (30/60/90 min) + termination per spec, transfer the defrost thermostat/sensor connections, then verify a forced defrost — that it terminates on temp/time and that it energizes aux heat + the reversing valve correctly.7 stepsLockedReplace a Reversing-Valve Solenoid Coil (Heat Pump)GuideCoil-only job — the solenoid coil slides off the valve stem, so NO recovery and NO brazing. Confirm the coil (not the valve) is the fault, match the coil voltage (24 V) and position, slide the new coil on, and verify the valve audibly shifts on a call.4 stepsLockedReplace a Defrost Sensor (Heat Pump)GuideReplace the coil defrost thermostat/thermistor, clip it to the correct spot on the outdoor coil tube (where the manufacturer specifies), verify its resistance-vs-temperature, then confirm defrost initiates AND terminates on temperature.5 stepsLockedReplace a Suction Accumulator (Heat Pump)GuideReplace the suction-line accumulator that protects the compressor from liquid floodback (common on heat-pump defrost / low ambient): recover, cut the old one out, braze the new accumulator in with flowing N2 in the correct orientation and flow direction (oil-return bleed at the bottom), install a new drier, then deep-evacuate and recharge.6 stepsLocked
Mini-split
Package unit
Thermostat
Components & procedures
Replace a Run CapacitorGuidePower off, bleed the cap, match µF + voltage, land HERM/FAN/C correctly, verify.8 stepsLockedLine Set Joints: Braze vs. ProPressGuideMake clean refrigerant joints two ways — brazed with a nitrogen purge, or pressed — then leak-check.9 stepsLockedEvacuation & ChargingGuidePull a deep vacuum, confirm a decay test, weigh in the charge, then verify superheat/subcool.5 stepsLockedInstall a Filter-DrierGuideOrient the arrow toward the metering device, braze with a nitrogen purge while heat-sinking the core, then pull a proper vacuum — and always fit a new drier when the system is opened.5 stepsLockedInstall a TXV (Thermostatic Expansion Valve)GuideMount close to the coil, clamp the sensing bulb on a clean horizontal suction line at 4–5 o'clock and insulate it, tie the external equalizer downstream of the coil, braze with N2 + heat-sink, then set/verify superheat.7 stepsLockedNitrogen Pressure / Leak TestGuidePressurize the refrigerant circuit with DRY NITROGEN through a regulator (never oxygen, never refrigerant) to the listed test pressure, hold and watch for pressure decay accounting for temperature, locate leaks by bubble/electronic detection, then relieve safely.5 stepsLockedRefrigerant RecoveryGuideEPA 608 required: connect a recovery machine to a DOT-rated recovery cylinder (never filled past 80%), recover liquid then vapor down to the required recovery vacuum level before opening the system, weigh the recovered refrigerant, never vent, and label the cylinder.5 stepsLockedReplace a 24 V Control TransformerGuideMatch the primary voltage (120/208/240) tap, the 24 V secondary, and the VA rating, FIND the short/overload that killed it (usually a shorted thermostat wire or a stuck/shorted contactor coil), protect the secondary with a fuse/breaker, and verify 24 V out under load.5 stepsLockedReplace a Condensate PumpGuideSwap the pump (mini-split / furnace / coil), verify the float operates, WIRE the safety/overflow float switch into the Y/24 V circuit so it cuts cooling on failure, fit the check valve and a sloped discharge line, then pour-test it.5 stepsLockedReplace a Schrader (Access-Valve) CoreGuideReplace a leaking Schrader/access-valve core UNDER PRESSURE with a core-removal/installation tool (no full recovery needed), seat/torque the new core, fit a sealing cap, and leak-check — the cheap fix before assuming a system leak.5 stepsLocked