A Quiet Room and a Noisy Undercounter Unit

Most calls about a noisy undercounter unit are really about a quiet room. Island houses remodeled into open plans, often with the bar or beverage center a few steps from the sofa and nothing but the lake beyond the windows, give a small compressor and its fans no background to hide in.

What counts as normal

A working unit makes a range of sounds, and in our experience humming, clicking, buzzing, a little vibration, fan noise and the occasional knock as something settles are all ordinary. They are simply more noticeable in an open-plan room and at night. Gurgling and hissing belong on the same list: water finding its way to the drain, and refrigerant moving through the evaporator.

In practice that covers the click as the compressor starts or stops, a steady hum while it runs, the whirr of the condenser fan behind the kickplate, and a trickle as water moves through the drain. Condenser fan noise is easy to mistake for the compressor, because on most models that fan starts and stops with it.

Sounds worth a call

What makes a noise worth a visit is change: a sound that is new, that grows louder over time, or that arrives alongside warmer temperatures. Three kinds deserve attention.

A fan that ticks, scrapes or grinds. The test is simple: open the door and listen. If the noise stops with the door open, it belongs to the evaporator fan inside the cabinet, which is a service call. If it carries on, look to the machine bay at floor level instead. Check too that nothing stored inside has been pushed against a fan grille.

A changed note from the machine bay. Louder, rougher or longer than it used to be. The first step there is a condenser cleaning if one has not been done in six to twelve months. After that, a noise from the condenser fan or the compressor is for us to diagnose.

Any noise with a burning smell. Switch the unit off at its own control panel and call for service.

Owner checks, and where they stop

Some noises belong to the room rather than the unit. A toe-kick board, a cabinet door or a stool leg touching the unit turns ordinary vibration into a rattle, and bottles on a shelf above can ring against each other. Touch the things around the unit while it runs and listen to what the sound does. Do not take panels off to find a noise; the fans and the compressor sit behind covers for good reason. If the sound is coming from the machine bay and it is new, the compressor and its start components are on our list, though they are rarely the first answer.

What we check

We listen with the door open and shut, with the kickplate off, and as the compressor starts and stops, then set what we hear against the cabinet’s temperatures. A noisy unit that is still cooling well often has a fan that is wearing; a noisy one that is struggling needs the whole picture. The visit is booked as refrigerator repair.

Before you call

1. Step 1

   Note when the noise happens

   At start-up, all the time, only at night, only after the door has been open? Write down what you hear and when.

2. Step 2

   Open the door and listen

   If the noise stops while the door is open, tell us. That pattern points at the fan inside the cabinet.

3. Step 3

   Touch what surrounds the unit

   Press lightly on the toe-kick, the side panels and nearby cabinet doors while it runs. A rattle that stops under your hand is the joinery.

4. Step 4

   Clear the grille and the shelves

   Move anything resting against the kickplate grille, and make sure nothing stored inside is jammed against the back wall.

Past these checks the fault is inside the machine. Call Mercer Island Sub-Zero Service on (206) 208-3377 and say which step changed nothing.

Asked about this

Our unit clicks now and then. Is that a fault?

Almost certainly not. A click as the compressor starts or stops and a steady hum while it runs are ordinary sounds on a healthy machine, and we hear both on units that test perfectly. It becomes worth a call if the clicking repeats without the unit ever starting, or if the cabinet is warming at the same time.

Why does the unit seem louder at night?

Because the house is quieter. The same running sounds stand out at night and in an open-plan room, and an island evening by the water has little else to cover them. If the same sound is louder than it was a month ago, that is different: note it and call Mercer Island Sub-Zero Service on (206) 208-3377.