Adjusting Your Walk in Cooler's Temperature

"Help! My product is freezing. What should I do? How do I adjust the temperature and what should I set it to?"

Here’s what’s going on: Air directly exiting the evaporator coil is approximately 10 degrees colder than the overall temperature in your walk in cooler. So, products placed too close to the coil may be damaged. You could adjust your shelving positions or make a temperature adjustment to warm the overall display. It should be operating between 38 to 42 degrees Fahrenheit. Read below for instructions on how to adjust your walk in cooler’s temperature!

If this does not remedy the problem, perform routine maintenance (read here for help with that). Ensure that the condenser coil is clean and make a slight temperature adjustment to warm your walk in cooler a few degrees. If there is no change, and the compressor is running continuously, there may be a problem with the control system. Place a service call to have your walk in cooler examined.

For more information about possible causes, read HVAC Fun's "Troubleshooting a Frozen Refrigeration Evaporator Coil", or check out our post, "My Walk in Cooler is Blowing Warm Air!"

BEFORE YOU ADJUST THE TEMPERATURE:

First, determine what the true temperature is in your walk in cooler. Immerse a floating aquarium thermometer in a vase of water somewhere inside. This will give an accurate reading as to the current set point. As stated previously, we recommend a setting somewhere between 38 to 42 degrees Fahrenheit for optimum performance. Perform normal preventative maintenance prior to any temperature adjustment being performed. Adjustments should not be made to compensate for poorly maintained equipment.

Now, if your product is freezing, you're probably not going to be lowering the temperature of your walk in cooler. However, I wanted to make this a complete guide, so it's important I mention these next few cautionary tips. Consideration should be given to these factors prior to lowering the temperature of your walk in cooler:

1. Each degree you lower the temperature will consume more energy, leading to higher bills.
2. Compressor run times will increase, decreasing the lifetime of the walk in cooler equipment. More heat and noise will be generated in your store.
3. The possibility of freezing product or iced coils will increase. Product loss wastes time and money—and is not covered by any equipment warranties.

ADJUSTING THE TEMPERATURE CONTROL:

IMPORTANT: These controls are very sensitive, so only make small adjustments, and let the temperature stabilize over a few hours. Don’t make any further adjustments before this.

If you determine that an adjustment is required, here are 3 steps to help you do so:

1. Locate the temperature control. Since it is supplied as a loose part for field installation, it may be mounted anywhere on your walk in cooler. Most typically, it will be mounted within the walk in cooler. It is a small unit, usually with two scales, adjustment screws, and a copper sensing probe off the bottom. Electrical conduit will enter the bottom of the control.

*** Be careful! All of our walk in coolers are also equipped with pressure controls and can appear very similar to temperature controls. They are usually mounted as part of the condensing unit. Only trained technicians should adjust these controls. The scales of pressure controls always refer to pressure (P.S.I., bar, etc.) rather than degrees of temperature.

2. There are two scales on the control. One scale measures the set point and the other scale shows the differential. The temperature swing or range of your walk in cooler is determined by the control set point, plus or minus the differential setting, depending on what model you have. It is usually not necessary to adjust the differential of the control.

3. There will be either a screw or a knob located directly above both scales. Turn the adjusting screw above the temperature scale to move the indicator towards the desired setting. Remember to move the indicator in only small increments at a time.

My Walk in Cooler is Blowing Warm Air!

Yikes! Your walk in cooler certainly shouldn't be blowing warm air. To begin, visually inspect the evaporator coil. Are the fins iced over?

If they are iced over, then either shut the walk in cooler down completely, or make a temperature adjustment to the warmest position (this shortens the defrost time). Leave the unit alone until the evaporator coil is completely free of ice—this may take a while if the build-up was heavy. Never attempt to manually defrost or remove built-up ice by hand or with tools as it could easily cause a refrigerant leak! Once clear, reset the temperature control to the correct range (38 to 40 degrees Fahrenheit).

If the evaporator coil is not iced over, or if the icing occurs again, place a service call to determine and correct the cause of the problem.

If the problem is temporary, the unit may have just been in a defrost period. Just to be safe, the settings on the defrost timer should be reviewed and adjusted if necessary.

More importantly, make sure you keep up to date on performing routine maintenance on your walk in cooler. There are some good tips in our post "How to Clean Your Walk in Cooler (5 Guidelines)"!

How to Clean Your Walk in Cooler (5 Steps!)

Normal maintenance on our walk in coolers is very easy. Well-maintained walk in coolers will experience very few mechanical failures, run efficiently, and last for a long time. It pays to uphold a regular cleaning schedule for your walk in cooler. You can determine how often your walk in cooler needs to be cleaned by the amount of use and how dusty the environment is. To begin with, though, we've complied five major guidelines that will help keep your walk in cooler running as efficiently as possible...

MONTHLY:

1. Clean the condenser coil of your condensing unit. First of all, it is considerably safer if you shut off the circuit breaker while you clean. A good way to clean your condensing unit is with a shop-vac (pictured to the left). Not only can you vacuum the surface, but also you can reverse the flow of air to blow deeply imbedded dust out from the center of the coil—blow it out from both directions as best you can. You can then wipe off the housing and compressor with a damp rag. This simple maintenance is the single most important thing you can do for your walk in cooler.

2. Clean the interior of your walk in cooler. Avoid using harsh cleaners that can damage the painted finish over time. Mild soap and water will normally be sufficient, especially if done on a regular basis. Hard water stains can be cleaned with a mixture of white vinegar and water; bleach and water can be used to clean mildew and mold. If you notice any of the caulk seals coming loose, pull them free. You can pick up small tubes of silicone at any hardware store to reseal the joint.

3. Check to make sure that the doors are sealing tightly to your walk in cooler. A visual inspection is all that is normally needed. You should be able to close the door on a dollar bill, and feel resistance when you pull the bill back out. If you need help adjusting your walk in cooler doors, read here!

ANNUALLY:

4. Clean your evaporator coil. Unfortunately, this is a lengthy process, but it is extremely important. Evaporator cleaning solutions are sold at refrigeration wholesalers by the bottle. They are specially formulated to clean the type of sediment that can collect over time in evaporators, and are also very easy to use (specific directions will be on the bottle). To begin, turn off the power to your walk in cooler. The drain tube should be disconnected, and the bottom pan of the evaporator coil can then be unscrewed and removed. Clean and disinfect the inside of the pan and follow the package directions to clean the copper tubing and fins of the coil itself. If you are uncomfortable with these procedures, you can always schedule a preventative maintenance service call with a refrigeration technician.

5. Clean your walk in cooler door gaskets (pictured to the right) with a soft cloth, soap, and water. Repair any small tears with a clear silicone adhesive. To keep them soft and pliable, wipe them down with a vinyl preservative, commonly sold at automotive supply stores. If a gasket should tear beyond repair, it’s worth being replaced—without a gasket, there will be significantly more wear and tear on your walk in cooler’s compressor.

Servicing Your Walk in Cooler

Like all equipment, refrigeration systems can malfunction. If that happens, we understand you need assistance quickly. We know it can be very stressful when your product is no longer staying cold! Who should you call first? Well, that depends...

If within initial 90 day labor period (factory installs only):

Your first call should be to SRC at our toll-free number: 800-521-0398. Our service department will determine if a service call is required and make the arrangements for you. If the failure is over the weekend or during a holiday and you can't wait to contact us, you can call our installers directly. If the repair falls under our equipment warranty, you will be reimbursed for the straight-time service charges incurred. You will only be responsible for the premium overtime amounts. Make sure you call our service department to inform us of the problem when normal business hours resume.

Beyond the labor warranty period:

Since you will be responsible for the labor portion of the repair, you are free to call any service provider you would like (as well as the original installers). You can also call SRC’s service department and we will gladly coordinate the call for you. If the technician determines that a part or component is defective and you are still within the one-year parts warranty, please have them contact our service department for replacement parts. Compressor motors are covered for a five-year period. Once again, have your technician contact us for instructions.

If you are unsure about your current warranty coverage:

Please call SRC’s service department. We will be happy to pull your job file and explain your existing coverage.

Walk in Cooler Leaking Water (Drainage System Malfunctions & More)

(Read here for more general information about walk in cooler drainage systems.)

If your walk in cooler is leaking water, there are two main sources to check...

1) The Evaporator Coil Drainage System

When the compressor is operating, the copper tubing and fins in the housing of the coil are colder than the air inside your walk in cooler. As air is forced through the coil by the fan motor, moisture will collect on these fins. This moisture will form droplets and fall into the bottom pan (this is part of the evaporator coil assembly). From there it will be directed into a drain hose, and eventually into the bucket, floor drain, or electric hot pan.

a) If the drain line becomes plugged or obstructed at any point, water will back up and spill over the edges of the coil. If this is the problem, the walk in cooler will need to be shut down so you can clean out the obstruction.

b) If the coil assembly is not pitched back towards the drain hose, water can pool in the front of the drain pan and leak from screw holes. Drain pans generally have a pitch designed into them, but if the walk in cooler itself is not level or pitched forward, it can defeat this design feature. Recheck if the walk in cooler is leveled properly. If more drain pitch is required, the evaporator coil assembly can be shimmed (allowing the water to flow freely back to the drain).

2) General Air Leaks

Whenever the cold air inside the walk in cooler meets the warmer outside air, moisture will form. Thus, if a floor or ceiling seam is not sealed properly, you may notice condensation or water droplets on your walls or floor. Your walk in cooler should be as level as possible—its seams will be tighter and the doors will shut more securely. Use a 100% silicone caulk to seal any seams where you notice condensation. (Read here for more information on caulking.)

When installed in a non air-conditioned warehouse, some walk in coolers will develop condensation on the outside of the walls or entry doors when the weather is warm and/or humid. Unfortunately, there is little that can be done to alleviate this situation. Sometimes, air movement in the form of a floor or ceiling fan can help reduce or eliminate the problem.