Goodman Air Conditioner noise diagnosis in Greater Vancouver
New noises from an air conditioner are worth taking seriously, because the machine was quiet yesterday and something changed. The trick is not identifying the exact part from a description. It is knowing which sounds mean keep going and book a visit, and which mean shut it off now.
Sound travels oddly around houses. A hum that seems to come from the hallway is often the outdoor unit transmitted through the line-set into a wall cavity, and a rattle that sounds catastrophic outside is sometimes a loose panel screw. So before guessing, we pin down the where and the when.
Everything below describes general fault categories rather than a specific diagnosis for your unit. Sounds mean different things on different models and vintages, and only measurement at the equipment settles it. If you ever smell gas near shared mechanical equipment or a CO alarm sounds, leave the home and call the gas utility and a licensed technician from outside.
Pin the noise down before anyone opens a panel
Five minutes of observation saves an hour of chasing. Stand outside beside the condenser while someone drops the thermostat to call for cooling, and listen through a full sequence: contactor pull-in, fan spin-up, compressor start, steady running, then shutdown.
Record four things. Where the sound originates, outdoor unit or indoor equipment. When it happens: only at start, only at shutdown, continuously while running, or randomly. How long it lasts, whether it is a one-second event or constant. And what the system does around it, meaning does it keep cooling, trip a breaker, or stop on its own.
Use your phone. A twenty-second video with audio, taken from a safe distance, is genuinely useful to a technician and often narrows the list before we arrive. Get one clip standing near the condenser and one at a supply register indoors.
Do not open the outdoor cabinet to investigate. The capacitor inside can hold a dangerous charge even with power off, and the fan blade sits directly under the top grille. Panels stay on. What you can safely do is check for obvious external causes: a branch against the fan grille, garden debris, a loose service panel, a rock in the base pan, or the unit sitting on a settled pad. Those account for a surprising share of noise calls in older neighbourhoods.
Banging and clanking from the outdoor unit
A hard bang is the one noise that earns an immediate shutdown. Turn the thermostat off, then pull the outdoor disconnect at the wall if you can do so safely, and leave it off until it has been looked at.
Metallic banging inside the cabinet generally falls into a few categories. Something foreign has entered through the top grille and is contacting the fan blade, which is common where cedar and fir hang over a sideyard. A fan blade has cracked or a set screw has backed off, throwing the blade out of balance so it strikes the shroud. Compressor internal mounting hardware has failed, letting the compressor shell shift and knock against the cabinet on start and stop. Or the compressor itself is failing internally, in which case the sound is a dull heavy thud rather than a sharp ring.
The pattern helps. A bang only at startup and shutdown, once each, often points to mounting or torque effects. Continuous banging while running points to something contacting a rotating part, and running it further turns a repair into a replacement.
One benign version exists. A single dull thud from the ductwork or an indoor plenum as pressure changes at startup is expansion noise, not damage, though sheet-metal oil-canning like that can usually be quieted with duct support or a pressure fix.
Rattling, buzzing and vibration you can feel in the cabinet
Rattle is the most common noise call we get and the least alarming, though it should still be traced. Put a hand flat on the cabinet, well away from the top grille, while it runs. If the rattle changes character under light pressure, it is a panel or fastener.
The usual suspects: service panel screws backed out, the top grille loose, a corroded fan guard, or the whole cabinet vibrating against a pad that has settled unevenly after a wet winter. Older Lower Mainland yards move. A pad that was level in 2015 rarely still is. Refrigerant line-sets that touch the house at a strap or pass through a joist without an isolator transmit that vibration straight into a bedroom wall, which is why a rattle can sound louder inside than out.
Other sources include a bent fan blade, debris in the base pan sliding around, and loose electrical components buzzing inside the control box, though that last one belongs to a technician.
What you can safely do: clear debris from around and under the unit, confirm nothing is leaning against the cabinet, and check that the pad has not tilted. What you should not do is remove panels to chase a rattle. If the noise is inside the control area or near the fan, leave it. Rattle that starts suddenly and grows quickly is worth a same-week look.
Electrical hum: contactor, capacitor and the sounds that mean stop
A cooling system has a normal operating hum, a low steady sound from the compressor and fan motor that you stop noticing after the first summer. The hums that matter are the abnormal ones.
The classic pattern is a loud hum with no movement. You hear the outdoor unit energize, the fan does not spin, the compressor does not start, and after a short time the breaker trips or the sound stops. That generally indicates a start-component or compressor-start problem, often a failed run capacitor, sometimes a seized motor. Do not spin the fan blade with a stick to help it along. Shut the system off at the thermostat and disconnect and book service, because running a motor that will not start cooks the windings.
A rapid chattering or clicking hum from the outdoor unit, repeating several times a second, generally points at the contactor or a control-voltage problem.
A persistent buzz that continues after the system has satisfied and shut down deserves attention too, since something is still energized that should not be.
Anything that smells hot, shows scorch marks, trips a breaker repeatedly, or produces a smell of burning plastic is a stop-now situation. Never reset a breaker more than once on the same fault, and never bypass a safety control to keep a unit running.
Squealing and screeching from motors and bearings
High-pitched squeal is almost always rotational. The question is which rotating thing.
On the outdoor unit, a squeal or grinding that rises and falls with fan speed points at the condenser fan motor bearings. Many modern motors are sealed and not serviceable, so the fix is motor replacement rather than lubrication, and a motor that has started to grind rarely gets better. If the fan is struggling, head pressure climbs and the compressor works harder, so a squealing fan is not a noise you should live with through August.
Indoors, squeal usually comes from the blower assembly in the furnace or air handler that moves your cooled air. Bearing wear, a blower wheel out of balance from accumulated dust, or on older belt-drive equipment a glazed or misaligned belt. A belt squeal is loudest at startup and often fades. A bearing squeal is steady and gets worse.
A short screech only in the first second or two of compressor start can be normal on some equipment and abnormal on others, so note it and mention it rather than assuming.
One genuine homeowner job sits here: replace a loaded filter and open closed supply registers. Restricted airflow makes blowers work harder and noisier, and in older homes with retrofitted ducting it is a frequent contributor.
Hissing, gurgling and bubbling: refrigerant and airflow
Hissing has two very different sources, and they get confused constantly.
Refrigerant hiss is a steady, fine sound, often near the indoor coil or along the line-set, sometimes accompanied by weak cooling, ice on the suction line, or a system that runs and runs without satisfying. A refrigerant leak is not a homeowner repair and it is not solved by adding refrigerant. Refrigerant handling requires certification, the leak has to be found and fixed, and topping up a leaking system just puts the same charge back into the atmosphere. Book it.
Gurgling or bubbling generally points to refrigerant flow conditions, which a technician confirms by taking superheat and subcooling readings at steady state rather than by ear. It can also come from condensate, and on a high-efficiency furnace paired with your coil, from the drain trap. A gurgle at the indoor unit with water around the base is a condensate drain problem, not refrigerant.
Airflow hiss is different: a broad whooshing or whistling at registers, at the filter slot, or at a duct joint. That is air moving too fast through too small an opening, usually from an undersized return, a clogged filter, closed registers, or a leaky duct connection. Older Vancouver housing stock with cooling added later is prone to it, and it is fixable with duct work rather than equipment work.
Clicking, popping and ticking, and which of those are normal
Not every noise is a fault, and knowing the normal ones saves you a service call.
Normal: a single firm click from the outdoor unit as the contactor pulls in at the start of a cycle and another as it drops out. A soft click from the thermostat. A brief tick or pop from ductwork as sheet metal expands when the blower starts and contracts when it stops, most noticeable in long straight runs in older homes. A short whoosh as the fan comes up to speed. Occasional water trickling at the condensate drain during humid weather.
Not normal: rapid repeated clicking at the outdoor unit, which suggests the contactor is chattering or a control circuit is unstable. Clicking that comes with the system starting and immediately stopping again, over and over, which is short-cycling and has many causes including airflow restriction, charge problems, a failing control, or an oversized unit. Popping that is loud, metallic and coming from the equipment rather than the ducts.
One pattern deserves its own mention: a system that clicks, tries to start, and trips out repeatedly is protecting itself. Something upstream is wrong. Let it lock out, leave the safety controls alone, and get it diagnosed rather than forcing repeated restarts, which is hard on the compressor.
Indoor duct noise and strata neighbour complaints
Two noise problems have nothing wrong with the equipment at all. Both come up constantly in Metro Vancouver.
The first is duct-borne noise. Cooling gets added to homes that were built for heating alone, and the existing ducting often was not sized for the higher airflow cooling wants. The result is register whistle, a roar in the room nearest the air handler, and booming as sheet metal flexes. Fixes are mechanical: adding return air, resizing a starved branch, replacing a crushed flex run, adding a lined transition or turning vanes, isolating the equipment from the structure. None of it requires new equipment, and all of it makes the system quieter and more efficient at once.
The second is the neighbour. Strata bylaws and municipal noise bylaws across the region regulate outdoor mechanical noise, particularly at night, and townhouse and duplex siting puts condensers close to bedroom windows. Read your strata bylaws and your municipality’s noise bylaw before assuming a complaint is unreasonable, and check with your strata council before relocating anything on common property. Real solutions exist: isolation pads or spring mounts, correct clearances, relocating the unit, and choosing equipment with a lower rated sound level, which is published on the manufacturer’s spec sheet.
HeatLand has been sorting out noise complaints across Metro Vancouver and the Fraser Valley since 1999. Call (604) 330-3812.
Quick Checklist
- Note whether the noise comes from the outdoor unit or the indoor furnace/air handler
- Record when it happens: at start, at shutdown, continuously, or randomly
- Take a short phone video with audio from a safe distance, outdoors and indoors
- Shut the system off at the thermostat and the outdoor disconnect for any hard bang, grinding, or burning smell
- Check outside the cabinet only: branches, debris, loose panel screws, a settled or tilted pad
- Replace a loaded filter and open closed supply registers before blaming the equipment
- Never spin a stalled fan blade by hand or with a tool, and never open the outdoor cabinet
- Never reset a breaker repeatedly or bypass a safety lockout to keep the unit running
| Sound | What it generally points toward | Keep running? |
|---|---|---|
| Hard bang or metallic clank | Foreign object, fan blade or mount failure, compressor mounting or internal failure | No. Shut off at thermostat and disconnect |
| Rattle or vibration | Loose panel, fan guard, settled pad, line-set contacting the structure | Usually yes, but book a look this week |
| Loud hum with no fan or compressor movement | Start component, contactor or seized motor problem | No. Shut off before windings overheat |
| Squeal or grind | Condenser fan or indoor blower motor bearings, or a worn belt on older equipment | Short term only; get it replaced before it seizes |
| Steady fine hiss with weak cooling | Possible refrigerant leak or flow restriction; needs measurement, not a top-up | No. Certified diagnosis required |
| Whistle or roar at registers | Airflow restriction: dirty filter, closed registers, undersized or leaky ducting | Yes; check the filter first, then have ducting assessed |
Frequently Asked Questions
My Goodman condenser banged once and stopped. Can I restart it?
Leave it off. A hard bang usually means something inside the cabinet contacted a rotating part or a mount let go, and restarting turns a contained problem into a bigger one. Switch the thermostat off, pull the outdoor disconnect if you can reach it safely, and book service. Do not remove panels to look, because the capacitor can hold a dangerous charge even with power off.
The outdoor unit hums but the fan does not spin. What now?
Shut it down at the thermostat and the disconnect. That pattern generally indicates a start-component, contactor or motor problem, and letting it sit and hum cooks motor windings. Do not push the fan blade with a stick to get it going, which is both unsafe and hard on the motor. A technician will check the capacitor against its rating, inspect the contactor, and read amp draw.
Is a hissing sound always a refrigerant leak?
No. Refrigerant hiss is a fine steady sound, often near the indoor coil or line-set, usually paired with weak cooling or ice on the suction line. Air hiss is broader whistling at registers, the filter slot or a duct joint, and that is a restriction problem. Change the filter and open closed registers first. If cooling is genuinely weak, it needs measured diagnosis, not added refrigerant.
Which air conditioner noises are actually normal?
A firm click as the contactor engages and again at shutdown, a soft click from the thermostat, a whoosh as the fan spins up, ticking or popping from ductwork expanding and contracting, and water trickling at the condensate drain in humid weather. Steady low hum from a running compressor is normal too. What is not normal is rapid repeated clicking, grinding, banging, or any burning smell.
My neighbour complains about the outdoor unit at night. What are my options?
Check your strata bylaws and your municipality’s noise bylaw first, since both commonly restrict outdoor mechanical noise overnight. Practical fixes include isolation pads or spring mounts, correcting clearances so the unit is not reflecting off a wall, servicing a noisy fan motor, and relocating the condenser away from bedroom windows. If it sits on common property, get strata council approval before moving anything.
Reviewed by the HeatLand Heating & Cooling team — licensed, insured, TSBC-certified HVAC contractor serving Metro Vancouver & the Fraser Valley since 1999. Error codes, specifications, pricing and rebate programs vary by model and change over time; confirm details against your unit’s own manual, a written quote, and the manufacturer or CleanBC/FortisBC. If you smell gas or your CO alarm sounds, leave the home and call the gas utility and a licensed technician from outside.