Refrigerator runs constantly, and never seems to shut off.
Often it is normal. GE says the compressors in its refrigerators and freezers are designed to run 80% to 90% of the time, and may approach 100% in a heat wave. Sub-Zero sets no normal run time at all, and says that on its two-compressor models the compressors can run at the same time or overlap, so the unit seems to run nonstop. Viking’s manuals say the motor naturally runs longer on hot days, after a large load of food and when the doors are opened often.
It is a fault when something comes with it: a compartment above its setting, frost, condensation, spoiled food, or a code on the display. Sub-Zero’s first step is a clean condenser and a day’s wait. In its service manual for the Built-In 600-2, the sealed system is the last of ten checks for a compressor that has run without rest.
On This Page
How Long Should a Refrigerator Compressor Run?
No maker gives one figure for every machine. Each figure below belongs to the model and the room named beside it.
| Maker and model | What it publishes about run time | Source |
|---|---|---|
| GE refrigerators and freezers, in general | Compressors designed to run 80% to 90% of the time; may approach 100% in an extremely hot, humid area or a heat wave | GE Appliances, normal run time |
| Monogram ZIS side-by-sides, GE’s 2002 service guide (ZIS360NM, ZIS420NM, ZIS480NM) | No load, set to 37°F and 0°F: running 41–46% of the time in a 70°F room, 53–55% at 90°F | Service guide 31-9091, p. 3 |
| Monogram ZIS side-by-sides, GE’s 2004 service guide, inverter compressor (ZIS360NR, ZIS420NR, ZIS480NR) | The same test: 60% at 70°F, 80% at 90°F | Service guide 31-9117, p. 5 |
| Monogram built-in side-by-sides, current manual | A variable-speed compressor designed to run for longer periods, for efficiency and noise | Owner’s manual 49-1000362 Rev. 8, p. 23 |
| Sub-Zero, every line | No set time. Combination models have two compressors, which can run at once or overlap | Sub-Zero, compressor run time |
| Sub-Zero 700TF-3 and 700TFI-3 tall freezers | The variable-speed compressor and both fans run a great majority of the time, and the manual calls it normal | Service manual #3758412, p. 3-12 |
| Sub-Zero Built-In 600-2, from serial 2092137 | The control logs code 40 after 6 hours of unbroken freezer compressor run, and 50 after 4 hours on the refrigerator side | Service manual #3758407, p. 3-14 |
| Viking 5 Series built-in (VCBB5363E) and 7 Series integrated (VBI7360) | The motor naturally runs longer on hot days, in a room that is too warm, after a large load of food, or with the doors opened often | Use and care manuals, p. 16 |
| Viking Veil integrated bottom-freezer (FDBMIC7360) | Two independent compressors; normal for one of the two always to be in operation | User guide, p. 34 |
GE’s two guides put the same line of side-by-sides through the same no-load test, two years apart: less than half the time in a 70°F room with a conventional compressor, 60% with the inverter. The rating tag says which row is yours: find your model number.
Why does a newer built-in run longer than the old one?
Because the compressor changed. GE’s 2004 guide for the Monogram inverter side-by-sides describes a variable-speed compressor with three speeds, 1,710, 2,100 and 3,120 rpm, chosen by how far the cabinet sits above its set point: 1 to 3 degrees for low, 6 to 19.5 for high. It draws 65 watts on low and 150 on high. GE’s support answer gives the reasoning: the greatest amount of energy is used as a compressor cycles on, not while it is running.
Sub-Zero’s service manual says of its variable-speed tall freezers, the 700TF-3 and 700TFI-3, that the compressor and both fans run a great majority of the time; they stop for a defrost, and may stop for short periods if the room is cool enough. Viking’s 5 Series manual describes a variable-speed DC compressor, and its Veil guide says the bottom-freezer model’s two independent compressors mean one of the two is always in operation. What Viking’s inverter does under load.
Two things make a Sub-Zero sound busier than it is. Its combination models, among them the 500, 600 and 700-2 Series, the 648PRO and the Classic and Designer combination units, carry two compressors, and when both run at once, or overlap, the sound does not stop. And on some older models the condenser fan runs continuously by design: Sub-Zero lists them by serial number, among them the 511, 532, 550, 561 and 590 before serial 1004775, with exceptions, and the 427R before serial 1944319. Sub-Zero notes that fan noise can be mistaken for the compressor. Which Sub-Zero series you have.
When Is a Long Run Expected?
Six conditions the makers name themselves. None of them is a fault.
- 01
The first day
Monogram’s manual and Viking’s 5 Series manual both allow 24 hours after the unit is first plugged in, and Monogram’s calls the long run normal. Viking’s Veil guide gives 6 to 12 hours to reach the selected temperature. For a new installation, Sub-Zero asks for at least 24 hours on and running.
- 02
A large load, or doors opened often
GE lists a large amount of food loaded at one time, especially warm or hot food, and every door opening, which lets cold air out and warm air in. Viking’s manuals name both. The current Monogram manual says the compressor and fans speed up with door openings and increased food loads.
- 03
A hot day, or a warm room
Sub-Zero’s guides say increased ambient temperatures may cause the compressors to run longer. Viking’s Veil guide calls a compressor on for extended periods normal in very hot weather, and Monogram’s table lists hot weather as normal.
- 04
Around a defrost
In GE’s 2002 guide for the Monogram ZIS, the board forces 30 minutes of continuous cooling before each defrost, then holds the compressor and fans off while the heater runs, up to 35 minutes, and through a 20-minute dwell. A Sub-Zero 600-2 freezer defrost lasts at most 20 minutes, with a 5-minute dwell. What a defrost cycle is.
- 05
A mode you switched on
Viking’s Fast Cool runs the 5 Series compressor at high speed for two hours, and its Max modes hold the coldest setting for four hours in the refrigerator and six in the freezer. A Sub-Zero Classic’s Max ice runs for up to 24 hours, during which some components may run at a higher speed.
- 06
A colder setting
Sub-Zero says a setting below the preset makes the unit run more, and Monogram’s table lists controls at the coldest setting. For a unit that runs continually, Viking’s service manual moves the control to medium.
The settings to aim for: the Department of Energy’s guide says 35°F to 38°F and 0°F. Sub-Zero recommends 38°F and 0°F, Viking’s 5 Series is preset to the same, and Monogram presets 37°F and 0°F.
How hot a room is each built-in rated for?
A warmer room means a longer run, and each maker publishes the room it means. They do not agree.
| Maker and series | The room it publishes | What it says about the edges | Source |
|---|---|---|---|
| Sub-Zero, all but its outdoor models | 60°F to 90°F | Outside it, performance suffers and damage may result. The warmer the room, the more the unit runs | Sub-Zero, running in warm temperatures; 600-2 manual, p. 8-9 |
| Monogram built-in side-by-sides | 55°F to 100°F, out of direct sunlight | Below 55°F it will not run often enough to hold temperature; above 100°F it will not perform properly | Owner’s manual 49-1000362 Rev. 8, p. 22 |
| Viking 5 Series built-in | Not below 60°F, and not near a heat source; no upper figure | The motor runs longer if the room is too warm | VCSB5424 installation guide 080499-000B, p. 17; VCBB5363E use and care manual, p. 16 |
| Viking Veil integrated | A climate class on the product plate: SN 50°F to 90°F, N 61°F to 90°F, ST 64°F to 100°F, T 64°F to 109°F | In very hot weather, a compressor on for extended periods is normal | User guide, pp. 12, 44 |
Phoenix averages 111 days a year at 100°F or more, and 21 at 110°F or more, by the National Weather Service’s 1991–2020 normals. An air-conditioned kitchen sits inside every range in the table; a unit outdoors, or in a garage with no cooling, does not. And heat costs run time before any limit is reached: at 90°F, the top of Sub-Zero’s range, GE’s inverter Monogram ran 80% of the time in the no-load test.
Sub-Zero draws the consequence itself: when a unit is not performing and the room is outside its range, no repair can correct the problem until the room is back within it. What a Phoenix summer changes inside the cabinet · a built-in in the garage or the outdoor kitchen.
Normal, or Worth a Call?
The sound alone decides nothing. What comes with it does.
| What you notice | Normal when | Worth a call when | Source |
|---|---|---|---|
| Running most of the day, both compartments on their settings | A variable-speed or two-compressor model; GE’s own figure is 80% to 90% | SERVICE, a code or Vacuum Condenser comes with it, and returns after the condenser is cleaned | GE, normal run time; Sub-Zero, EC40 |
| Running all day in a heat wave or a warm room | Sub-Zero, Viking and GE all tie a hot room to longer runs | It cannot hold its setting. Outside 60°F to 90°F, Sub-Zero says, no repair corrects that until the room is back in range | Sub-Zero, indoor unit temperature range |
| Running for hours after groceries, guests or a door left open | GE, Monogram and Viking each name it | Still off its setting after 24 hours | Viking manuals, p. 16; Monogram 49-60128-2, p. 25 |
| Running constantly, and warm | Not normal: Sub-Zero lists elevated temperatures among the signs of excessive running | With EC 40 on a Sub-Zero: more than 10 degrees above the setting, the door not left ajar for a long period. Above 48°F at a 38°F setting, a cleaning is unlikely to bring it back | Sub-Zero, EC40; warm refrigerator troubleshooting |
| Running constantly, with frost, ice or condensation inside | Not normal: the same Sub-Zero list | The condenser is clean, the door shuts, and it continues; or the gasket has rips or tears | Sub-Zero, compressor run time; Classic guide, p. 24 |
| HIGH TEMP, oPn or Shr on a Viking display | Not a long run: an alarm | Now, with the display written down first | Viking SMR-0022, pp. 11, 33, 34 |
In our view the thermometer is the test, not the sound. What the alarms mean · what each code means.
What to Check, in the Makers’ Order
Seven checks, each from a maker’s own list.
- 01
The display, and a thermometer
Write down any code before anything is switched off: on a Sub-Zero 600-2, switching the unit off and on is one way a flashing SERVICE is cleared. Then read the temperature in each compartment.
- 02
The condenser
Sub-Zero’s first step when a compressor seems to run excessively. Its Classic and Designer guides ask for a cleaning every 6 to 12 months, power off at the control panel, with a soft bristle brush and a vacuum: behind the flip-up grille on a Classic, behind the kickplate on a Designer. A Viking Veil shows CHECK COND. every six months. By maker: Sub-Zero · Viking · Monogram.
- 03
The doors and drawers
Sub-Zero’s guides ask whether the door closes properly and whether it was left ajar. Viking’s Veil guide adds food or containers in the way, and Monogram’s manual a gasket out of position. The Department of Energy’s test is a sheet of paper shut in the door: it should hold fast. How to test a door seal · a door that will not close.
- 04
The interior light
GE lists an interior light that stays on behind a closed door among the things that add to run time, and Sub-Zero’s service manual checks that the lights go out when the light switch is pressed. Where the switch is.
- 05
The settings and the modes
Back to the maker’s recommended settings, with any Max or Fast Cool mode allowed to finish. Sub-Zero and Monogram both allow 24 hours for a new setting to take hold.
- 06
The load and the vents
Sub-Zero says its units work best 25% to 75% full: too much food can block the airflow, and too little, or none, makes the unit run more. GE adds blocked air vents in the freezer section.
- 07
The room, and the air around the unit
The room against the table above, then the path of the air. Viking’s installation guide keeps the ventilation openings clear. Sub-Zero warns that a kickplate completely covered by a custom toe kick, on a 700 Series or Designer unit, can cause problems, sealed-system failure among them.
Then give it a day, and read the thermometer again.
What Does Constant Running Point To?
When it is not the room, the load or a setting, the makers’ service documents name what is left. The compressor comes last: what gets mistaken for a failed compressor.
| What you notice | What to check | What the makers’ lists point to | Source |
|---|---|---|---|
| Runs without rest; dust on the grille or kickplate, or no cleaning in a year | The condenser, with the unit switched off | Heat cannot leave the coil. First on Sub-Zero’s list; third on Viking’s for a unit that runs continually, after the setting and the door seal | Sub-Zero, compressor run time; Viking SMR-0022, p. 39 |
| Runs without rest; frost, ice or condensation inside | The door, and the gasket for dirt, tears or a section out of place | Room air getting in. Viking’s 3 Series manual says a damaged or torn gasket makes the unit run for longer periods | Sub-Zero Classic guide, p. 24; Viking 077784-000C, p. 24 |
| Still running without rest after a cleaning, a compartment drifting warm | Nothing more from outside | On a Sub-Zero 600-2, the manual’s lists name the condenser fan, the evaporator fan, a thermistor misreading, and a heavily frosted evaporator | Sub-Zero 600-2 manual, pp. 8-4, 8-7, 8-8 |
| oPn or Shr on a Viking VCRB display | Write it down, and call | A sensor open or shorted. The control keeps cooling as if the cabinet never reached its cut-out temperature | Viking SMR-0022, pp. 11, 33, 34 |
| Temperatures normal, and Vacuum Condenser keeps returning, on a Sub-Zero 600 before serial 1810000 | The condenser; then service | Condenser airflow first: dust, the fan blade, the fan motor, the board’s power to it. The manual adds possible early signs of a sealed-system leak | Sub-Zero manual #3756270, p. 8-10 |
| Every row above ruled out | A technician’s gauges | The sealed system: a leak, a restriction or an inefficient compressor, the last step in Sub-Zero’s guide for codes 40 and 50 | Sub-Zero 600-2 manual, p. 8-4 |
How long should you wait before calling?
A day. Sub-Zero allows 24 hours for temperatures to return after the condenser is cleaned or a setting is changed. Monogram’s manual allows 24 hours after the refrigerator is first plugged in and after a new setting; Viking’s 5 and 7 Series manuals, 24 hours to stabilize after hot food or a door left open. A Viking Veil’s guide gives 6 to 12 hours to reach a selected temperature.
Some lines do not wait. With EC 40 flashing, Sub-Zero asks for service when a compartment is more than 10 degrees above its setting and the door was not left ajar for a long period, and asks that a code not be cleared while temperatures stay high. It says a refrigerator above 48°F at a 38°F setting is unlikely to recover from a condenser cleaning. And when temperatures have not returned within 24 hours of a cleaning, or Vacuum Condenser comes back, its next step is service.
What this page is not: a guide to a refrigerator that is warm on both sides or silent (not cooling at all), or to a sound that is new or getting louder (which noises are normal). Nor is it a diagnosis. The lists name what can keep a compressor running; only measurement says which one it is.
When is it a visit?
When the checks are done, a day has passed, and it still runs without rest with a compartment off its setting. When a code or message comes back after a cleaning. And at once when the machine says so itself: SERVICE with high temperatures on a Sub-Zero, or HIGH TEMP, oPn or Shr on a Viking. Still inside the maker’s warranty? Call the maker first. Is the built-in still under warranty?
The diagnostic visit is $119 for the first appliance and $69 for each additional appliance on the same visit, and both are waived if you go ahead with the repair. A repair on one of the four makes, made with the genuine parts we supply, carries a 12-month warranty on parts and labor. What we repair on a Sub-Zero · on a Viking · on a Monogram.
Call (478) 888-2999, every day, 7am–6pm, and tell us the make and what happened.
Questions
Is it normal for a refrigerator to run constantly?
Often, yes. GE says the compressors in its refrigerators and freezers are designed to run 80% to 90% of the time, and may approach 100% in a heat wave. Sub-Zero gives no set run time, and Viking’s manuals say the motor naturally runs longer on hot days, after a large load of food and when the doors are opened often. It is a fault when warm temperatures, frost, condensation or a code come with it.
Why does my Sub-Zero run all the time and never shut off?
Sub-Zero’s combination models carry two compressors, and Sub-Zero says they can run at the same time or overlap, so the unit seems to run nonstop. On some older models the condenser fan also runs continuously by design. If the compressor seems to run excessively, Sub-Zero’s first step is to clean the condenser, which its guides ask for every 6 to 12 months, then to check that the door closes and was not left ajar.
Why is my Viking refrigerator always running?
Viking’s 5 and 7 Series manuals answer a motor that seems to run too long in one line: it naturally runs longer on hot days, if the room is too warm, after a large amount of food is added, or if the doors are opened often. Viking’s service manual for the VCRB all-refrigerator lists what to check when a unit runs continually: the control setting, the door seal, a dirty condenser, the condenser and evaporator fans, the thermistor and the control board.
Does a hot kitchen or garage make a refrigerator run constantly?
Yes, and the makers publish it. In the no-load test in GE’s 2004 service guide, a Monogram side-by-side with an inverter compressor ran 60% of the time in a 70°F room and 80% at 90°F. Sub-Zero designs its indoor units for 60°F to 90°F, and Monogram’s manual sets 55°F to 100°F. Sub-Zero adds that when a unit is not performing in a room outside its range, no repair can correct it until the room is back within the range.
How long should I wait before calling for service?
A day, by most of the makers’ own lines. Sub-Zero allows 24 hours for temperatures to return after a condenser cleaning or a change of setting, and Monogram’s and Viking’s manuals allow 24 hours to stabilize. Do not wait when a Sub-Zero flashing EC 40 is more than 10 degrees above its setting and the door was not left ajar for a long period, or when a code returns after a cleaning.
Sources
- Sub-Zero answers: compressor run time; Sub-Zero runs too much; condenser fan motor operation.
- Sub-Zero answers: running in warm temperatures; indoor unit temperature range for installation; refrigerator and freezer temperature settings; warm refrigerator troubleshooting; clean the condenser; error code EC40 and Service flashing; error code EC50 and Service flashing; Vacuum Condenser flashing.
- Sub-Zero Classic Series Refrigeration Use and Care Guide (11/2024), pp. 8, 18, 23, 24, and Designer Series Refrigeration Use and Care Guide (06/2024), pp. 22, 23: preset temperatures, Max ice, condenser cleaning, and the list for a unit that runs excessively.
- Sub-Zero Built-In (600-2) Series technical service manual, Job Aid #3758407, Revision B, August 2006: freezer defrost (p. 3-13), codes 40 and 50 and the ways SERVICE is cleared (p. 3-14), the ten test steps for those codes (p. 8-4), the fan and frost lists (pp. 8-7, 8-8), the room between 60°F and 90°F (p. 8-9).
- Sub-Zero Integrated (700-3 Tall) Series technical service manual, #3758412, Revision C, December 2013: the variable-speed 700TF-3 and 700TFI-3 (pp. 1-7, 3-12). Sub-Zero 600 Series (prior to serial 1810000) technical service manual, #3756270, Revision B, January 2006: normal temperatures with Vacuum Condenser flashing (p. 8-10).
- GE Appliances support answers: Refrigerator or Freezer – Normal Run Time, and Refrigerator – Normal Cycle Times: 80% to 90%, a heat wave, and what adds to run time.
- GE technical service guides for Monogram side-by-sides: 31-9091 (03/02), ZIS360NM, ZIS420NM and ZIS480NM: no-load running time (p. 3), defrost (p. 20); 31-9117 (04/04), inverter models ZIS360NR, ZIS420NR and ZIS480NR: no-load running time (p. 5), compressor speeds and wattages (p. 55).
- GE Appliances, Monogram owner’s manual for built-in side-by-side refrigerators, 49-1000362 Rev. 8 (04-26): presets (p. 10), the room (p. 22), troubleshooting (p. 23). Monogram owner’s manual 49-60128-2 (2002): the same troubleshooting row, and 24 hours after a door left open (p. 25).
- Viking use and care manuals: 5 Series VCBB5363E / FDBB5363E, F21416B (120115), pp. 5, 6, 7 and 16; 7 Series VBI7360 / FBI7360, 080282-000 (070122), p. 16.
- Viking Veil integrated user guide (080725), pp. 12, 18, 34, 44, 46; Viking 3 Series RVFFR336 use and install manual, 077784-000C (021523), p. 24; Viking VCSB5424 installation guide, 080499-000B (080326), p. 17.
- Viking Preferred Service manual SMR-0022, built-in all-refrigerator VCRB5301 / VCRB5361, May 2012: a failed thermistor that keeps the unit cooling (pp. 11, 33, 34), HIGH TEMP (p. 33), a unit that runs continually (p. 39).
- U.S. Department of Energy, Consumer Guide to Kitchen Appliances, DOE/EE-2475: the settings, and the sheet of paper in the door.
- National Weather Service Phoenix, historical extreme temperatures: days at 100°F and 110°F or more, 1991–2020 averages.
Written from these sources, each checked on (checked again ), and reviewed the same day by Aphelion Appliance Repair, Phoenix. Run times, speeds and room ranges belong to the models named beside them, and other models differ. Nothing here is a manufacturer’s instruction, and work inside a sealed system is a technician’s job.
Read Next
- Not cooling at all, before anyone says compressorWarm on both sides, or silent: what the three makers check first, and why the compressor comes late, if at all.
- What a Phoenix summer asks of a refrigeratorRoom heat, condenser dust and monsoon outages, and five checks before you call.
- The door gasket: test it, clean it or replace itThe paper test, what a failing seal looks like, and what a gasket costs for a Sub-Zero, a Viking or a Monogram.
- Sub-Zero compressor failed: replace it, or the refrigerator?The part, the sealed-system warranty that runs to year twelve, and the price of a new built-in.
Running all day, and warmer?
Tell us the make, what the display shows and how long it has been running. We answer every day, 7am–6pm.