FOB Detectors: Stop Beer Waste | Wholesale Beer Parts

Pacific Beer Equipment FOB detector, the standard foam on beer valve for long draw draft systems

A FOB detector, short for "foam on beer," is a small valve installed in a long draw beer line that automatically shuts off flow the moment a keg runs dry, before foam and air can push through and waste the rest of the line. If you run a long draw system with even one remote cooler, a FOB detector is the single cheapest piece of equipment that stops a keg change from turning into a bucket of foam down the drain.

What does a FOB detector do?

Inside a FOB detector is a small float that rides on top of the beer as it flows through. As long as liquid beer is present, the float stays down and beer passes through normally. The moment a keg kicks and the flow shifts from beer to foam and air, the float rises and closes the valve, stopping flow before that foam and air travel through the rest of the trunk line to the tower.

Without a FOB detector, a kicked keg on a long draw system keeps pushing air and foam through the line until someone notices, which means the beer that was still sitting in that line gets wasted along with it. According to bar inventory analysts Bar-i, a well run draft system should achieve a keg yield of 95% or better, while systems with poor line design or unmanaged keg changes commonly drop closer to 90%. A FOB detector is one of the lowest cost ways to close that gap.

Do I need a FOB detector for my system?

FOB detectors matter most on long draw systems, where beer travels through 25 feet or more of trunk line between the keg cooler and the tower. The longer that line, the more beer is sitting in it at any given moment, and the more you lose every time a keg kicks without one.

Long draw, remote cooler: a FOB detector is close to essential. Every keg change without one wastes a full line of beer as foam.
Direct draw kegerator, keg right under the tower: the trunk line is short enough that the waste from a kicked keg is minor, so a FOB detector is a nice to have rather than a must.
Multiple taps sharing a cooler: a FOB on each line means a kicked keg on one tap does not affect service on the others while staff swap the empty.

What types of FOB detectors are available?

Every FOB detector does the same basic job, but they differ in body material, inlet and outlet configuration, and whether the shutoff is a simple mechanical float or an automatic sensor.

Model	Price	Best for
Pacific Beer Equipment FOB	$55.95	Standard long draw systems, the most common pick
Pacific Beer Equipment FOB, Stainless Steel	$114.95	Coolers with condensation or wash-down cleaning where plastic bodies degrade faster
Plastic Body Series FOB (UDS)	$59.95	Compact installs using push-fit John Guest fittings
Tecflo FOB, Classic Style	$57.95	Installs that need a left inlet and bottom outlet configuration
Tecflo smartFOB Detector	$59.95	Automatic shutoff the instant a keg kicks, less reliance on the float alone
PRO-MAX Keg Foam on Beer Detector	$147.49	Commercial wall mount installs where a stainless housing is standard

Pacific Beer Equipment FOB foam on beer detector

How do I know if my FOB detector is bad?

A worn or stuck FOB causes two opposite symptoms depending on how it fails:

Stuck closed: beer flow is weak or stopped even though the keg is far from empty. The float is not resetting properly and needs to be manually released or the unit needs service.
Stuck open: foam and air pass through even with a full keg connected, which defeats the whole purpose of having a FOB installed. This usually means the float mechanism or seal has worn out and the unit needs to be replaced.

Most mechanical FOBs have a manual release knob for exactly the stuck closed case, so try that first before assuming the unit has failed outright. If the same FOB needs manual releases on a regular basis, treat that as a warning sign that it is nearing the end of its service life rather than a one time fluke.

How do I install and maintain a FOB detector?

A FOB detector mounts inline on the beer line inside the cooler, upstream of where the line enters the trunk to the tower, with the arrow on the body pointed in the direction of flow. Most units include a small drain port for the foam and beer that collects when the float trips, and running that drain to a bottle or bucket keeps the cooler floor dry instead of letting it pool.

Beyond that, a FOB detector needs very little maintenance: rinse the internal float and housing during your regular beer line cleaning cycle, and replace worn gaskets, vent assemblies, or release knobs as they wear rather than replacing the whole unit.

Frequently asked questions

What does FOB stand for in draft beer systems?

FOB stands for foam on beer. A FOB detector is a valve installed in the beer line that senses the switch from liquid beer to foam and air when a keg kicks, and automatically shuts off flow to stop waste.

Do I need a FOB detector on a direct draw kegerator?

Not usually. Direct draw systems have a very short beer line between the keg and the faucet, so the amount of beer wasted when a keg kicks is small. FOB detectors matter most on long draw systems where 25 feet or more of trunk line is full of beer at any given moment.

How much beer does a FOB detector actually save?

It depends on trunk line length and how often kegs are changed, but a FOB detector prevents the entire line's worth of beer from being pushed out as foam every single time a keg kicks unattended. On a long draw system changing kegs several times a week, that adds up quickly compared to the roughly $56 cost of a standard unit.

Why is my FOB detector blocking flow even though the keg is full?

The float is most likely stuck closed from the last keg change. Most mechanical FOBs have a manual release knob on the body that resets the float. If a regular manual release becomes necessary, the internal mechanism is likely wearing out and the unit should be replaced.

Should I choose a plastic or stainless steel FOB detector?

Plastic body FOBs are the standard choice and hold up fine in a typical walk-in cooler. Stainless steel is worth the extra cost in coolers with heavy condensation, wash-down cleaning, or where the unit is exposed to more wear than a normal installation.