Uh oh. Your walk-in is warm again, isn’t it? Sometimes you just can’t catch a break. In Texas’ unrelenting summer heat, a warm walk-in is never good news. Well we’re going to go over ten things to check on your walk-in that could be the problem. Hint, 80% of the time it is not low on refrigerant. The information below is for educational purposes. If you attempt any diagnosis on your own based upon what is written here, you are responsible for your actions but you know that already, don’t you? This began as a short list of possible problems with short descriptions and morphed into thousands of words about what could be wrong with your cooler and what steps we take to solve the problem. Considering this, I broke this post up into multiple blog posts rather than overwhelm readers with thousands of words. They are useful words but too many might be less than helpful.
10 common reasons why your walk-in isn't working. Part 1:
1. Dirty Coils
If there was one thing I could shout from the rooftops to help people extend the life of their refrigeration systems it would be to clean the coils. This is a problem on all kinds of cooling equipment from ice machines to air conditioning and when ignored can rear its ugly head in super annoying ways. Dirty coils are one culprit behind a walk-in warming up for our new customers. If they are established customers who have us PM their equipment that is usually not the case. Dirty coils prevent airflow that keep the system operating normally. For a walk-in there are usually only two types of coils.
Condenser coils are outside typically and get clogged with all kinds of dirt, pollen and other junk. If these are not kept clean this can lead to a warm walk-in but even worse can lead to compressor failure and oil breakdown in the system due to constant overheating. We typically clean this coil with water though it is fairly common to clean the coil with a stronger coil safe cleanser if the coils have a grease issue.
The evaporator is inside of the walk-in and can clog up as well. Dust, grease, plastic bags, paper all can get sucked into the evaporator coil. This issue will cause your walk-in to heat up as well but it does it by freezing the coil. If the evaporator coil does not have enough airflow the coil temperature drops and freezes the moisture in the air to the coil. This often creates a block of ice which is cold but allows no air to circulate around the room causing the walk-in to heat up. By this time you are calling us to come and fix the walk-in. During our visit we will melt ice from the coil and clean the coil with high pressure dry nitrogen or with water if possible. Just like the condenser coil we may also clean the evaporator coil with a coil safe cleaner if we find grease is an issue.
2. Thermostat
I did an exhaustive explanation of the thermostat in a previous post but it is basically just a switch that turns on and off the cooling when the temperature rises and falls. The first step is to always check for power at the thermostat with a handheld voltmeter. If there isn’t power going into the thermostat, your issue is somewhere else. A few things can go wrong with a thermostat but they are not something you can check without a voltmeter and an understanding of the electrical circuit. Here’s what we do to begin diagnosis on a mechanical thermostat:
The first possibility is that the thermostat can become uncalibrated. This means that it is no longer reading the temperature correctly and is turning the cooling on and off at the wrong temperature. This can be diagnosed by noting the room temperature and turning the temperature knob up and down slowly to see what temperature it turns on and off the cooling. Depending on the system, we may hear the distinct clunk of the solenoid turning off and on or if that is installed with the condenser we may hear the refrigerant flowing in your evaporator or it starts and stops. We also also check the amp draw on the wiring of the thermostat to determine if something is drawing power. If the refrigeration doesn’t come on and off as we are turning the thermostat knob at the desired temperature then that could be the problem. It takes a trained ear to hear when the system is going on and off as you turn the thermostat knob.
The second thing that can go wrong is that the thermostat can stick open or closed. This means that the switch that turns on the cooling stops working and is either stuck in the open or closed position. This has two effects. The first is that it never turns on the cooling and your box gets warm. The second is that the cooling is stuck on and will run until your walk-in is below the temperature it’s supposed to be. That’s not an emergency if your walk-in freezer is too cold but could be a real problem if it is a walk-in cooler. When turning the knob on the thermostat we should hear a quiet click from the thermostat as it turns. That click is the switch inside of it opening and closing. If that is not happening then there is an issue with the thermostat. This is something that might be inaudible with all of the other noise in the walk-in.
We'll continue this series of 10 common reasons your walk-in isn't working next week when we talk about the defrost time clock and the contactor. Check back in or add us to your RSS feed so you don't miss it. If you are having trouble with some of your refrigeration equipment in Austin, TX or in Lubbock Texas give us a call for service or new equipment. We are always happy to help. 512-651-4565 in Austin and 806-787-4985 in Lubbock, Texas Or Visit our website at https://www.tripointrefrigeration.com