Why Is My Fog Machine Not Making Fog?

This page has no product recommendations on it, deliberately. Every real fix here is a check, a clean or a part specific to your machine, and bolting a tenuous purchase onto a troubleshooting page would make it worse rather than better. You can read how we decide that on our editorial policy page.

1. Fluid

• Is there fluid in the tank? Obvious, and it is the answer more often than anything else, especially on a machine that ran fine an hour ago.
• Is the intake tube actually in the fluid? The tube floats or curls up as the level drops, and a tube sitting above the fluid means the pump is drawing air. Push it to the bottom of the tank.
• Is the fluid the right type? Wrong-specification fluid can carbonize in the heater and clog the nozzle, which is step 4 on this list and a much worse problem.
• Is the fluid contaminated? Debris in an opened container blocks the intake filter.

2. Heat-up

Almost every fog machine refuses to fire until it reaches temperature, and this is by far the most common false alarm. Heat-up times vary from a couple of minutes to considerably longer on larger machines, and a cold night lengthens it.

Most machines have a ready indicator. If yours does not, give it the manufacturer's stated heat-up time before concluding anything. And note that a machine which has been fogging heavily will drop below temperature and pause to reheat — that is duty cycle, not a fault.

3. The pump

With the machine up to temperature, press the trigger and listen. You should hear the pump click or buzz.

If there is no pump sound, check the remote first. Wired remotes fail at the connector and wireless ones lose pairing in cold weather, and both look exactly like a dead machine.

4. The nozzle

A clogged nozzle is the classic second-season failure, and the cause is almost always the same: the machine was stored with fluid residue in it, which dried and hardened over ten months.

Symptoms are a pump that runs normally with little or no output, or a weak spluttering stream instead of a proper plume. Consult your manufacturer's cleaning instructions — most specify a cleaning solution run through the machine, and some sell a dedicated cleaner. Do not poke a hard object into the nozzle, and do not run anything through the machine that the manufacturer has not specified.

5. Output that is there but wrong

• Thin, wispy output — usually the machine is not fully up to temperature, or it is mid duty cycle.
• Fog that vanishes instantly outdoors — that is wind, not a fault. No machine holds fog in moving air.
• Fog that rises instead of creeping — that is normal for a standard fogger, and it is physics rather than a failure. See how to make fog stay low.
• Wet spray rather than fog — the machine is firing below temperature. Wait for it, and stop triggering it while it heats.

Preventing next year's version of this

1. Run cleaning solution through before storage, per your manufacturer's instructions. This single habit prevents most nozzle clogs.
2. Empty the tank rather than storing it full. Fluid left standing invites contamination.
3. Store it dry and indoors. A fog machine is a heater and a pump in a plastic case; a damp garage floor is not where it should spend ten months.
4. Keep it out of the rain during the season too. A vented outdoor box if it must live in the yard, and bring it in at the end of the night.
5. Use fluid specified for your machine's wattage. Printed on the bottle, and the cheapest failure to avoid.

If the machine turns out to be genuinely dead, the fog machine roundup covers what to replace it with, and low-lying versus standard is worth reading first so you buy for the effect you actually want.