in Chiller Tube Cleaning, HVACThis week’s post ends our series on “Spring cleaning” your facility’s cooling system. You can download our three printable HVAC cleaning checklists for reference:Checklist 1: How to Clean Chiller Tubes Checklist 2: How To Clean Air Conditioner Coils Checklist 3: How to Clean Cooling TowersThis last post in our HVAC “Spring Cleaning” blog series addresses how to properly clean your cooling system’s air conditioner coils.In 2015, subscribers who read this article also: Searched Coil Cleaning Systems & ChemicalsPurchased CoilShin Coil Cleaning SolutionDownloaded HVAC “Spring Cleaning” ChecklistsDirt and grime build up on air conditioner coils if they’re not cleaned, causing the system to work harder. Not only that, but dirty air conditioner coils increase the cost to run your system and decrease cooling.Dirty coils also reduce the life span of your equipment and they interfere with the adequate heat transfer, requiring more electricity to run the system. 

Dirty evaporators can spread mold and other contaminants, causing poor indoor air quality, which leads to the potential for people to experience respiratory issues.A clean system lasts longer, works at peak efficiency and saves the cost of expensive repairs. You can improve the efficiency of your cooling system 16% just by cleaning the evaporator and air conditioning coils.Pressurized water pushes dirt back out of the coils, but using too much pressure can bend the coil’s delicate fins. The aluminum fins, responsible for heat exchange, become permanently ruined if they’re bent. Heat and steam aren’t recommended to clean coils as they cause high pressure within the coils, potentially damaging them.Our step-by-step “How to Clean Air Conditioner Coils” checklist walks you through the process for cleaning both air handler and condenser coils. Goodway’s two-speed vacuums remove dry debris from tight spaces and blow off dirt and dust. A coil cleaner outfitted with a low pressure fan nozzle washes debris from coils, keeping the pressure below 140 psi to protect coils from damage.

Adding a biodegradable, nontoxic foaming detergent to the cleaner penetrates and loosens tough dirt and grime from coils. Spraying a mold inhibitor on the coils after cleaning prevents the growth of mold, mildew and other contaminants. Adding biocide tablets to the drain pan keeps slime and other bacterial growth from building up for at least three months.Roof Air Conditioner Water Leaks A fairly common complaint is that of water leaks from the rooftop air conditioner. ac window unit with thermostatThese do not have to be nearly as hard to find or fix as people often make them- they simply need to be dealt with in a systematic method.ac inside unit not turning on The first question when dealing with this type of leak is- does it leak when it's raining or when the air conditioner is running (or, more rarely, both)? fan on ac unit not running

To deal with either, we need to look closely at how the air conditioner is mounted, and how it deals with the condensation generated while running. The main thing to keep in mind, is that the air conditioner is sealed to the roof using a sponge rubber gasket- this gasket is compressable, and really is a long term maintenance item (they can last years, but not forever). This gasket is compressed by 3 or 4 bolts running from the inside assembly up to the top. For either "rain only" or "while A/C is running" leaks, first make certain there is at least 1/2 inch of gasket left (it is not tightened right down to the roof), then check the bolt for tightness- just make sure they are all snug, but don't over tighten- there must be the gap between the bottom of the A/C and the roof. The reason for this gap is that on most roof top A/C/ units, the condensation drains out the bottom of the unit- between the base of the air conditioner and the roof. For this reason, never, ever seal around the perimeter of the air conditioner- I cannot say how many times I have had to deal with a unit where someone slopped goop around the base of the air conditioner, trapping water in where it has to leak inside.

The "inside"coils of the air conditioner sit in a drain pan, to collect the condensation, which then runs out a small hole in the side, and out the bottom. If the leak is both while raining, and while running, and the gasket is still thick enough and tight, odds are there is some roof deterioration underneath the air conditioner- as long as the roof isn't sagging, causing water to puddle up around the air conditioner, which can be checked by pulling a string across the roof, from side to side. If there is significant sag, the air conditioner needs to be raised, either by installing 2 gaskets or by removing the air conditioner and putting shimmed between the roof material and roof frame- this is the method I usually use, building up with strips of 1/4" plywood, until the air conditioner is high enough that water cannot run in. Of course, roof sag may be an indication of a larger problem, but quite often it is just age, and other than a bit of sag, there are really no structural problems.

If the leak is only while the unit is operating, first check all of the above, if everything checks out, odds are that the drain holes are simply plugged up, or that the evaporator coil is very dirty, which will cause enough suction to keep the water from draining properly. To deal with this, we have to get up on the roof, and do some disassembly. You have to remove the plastic shroud, and then the front evaporator cover, which is usually held on by a number of screws. This will get you in to the evaporator and drain pan- it is usually fairly obvious if the drains are clogged, and they are easily cleaned, but if you are going this far, it is a good time to check the evaporator coils for dirt, and clean them if needed (if they haven't been cleaned in a while, it really wouldn't hurt to clean them. Coleman recommends "Formula 409" cleaner, which works well- I use "VoomRV", but most mild degreaser type cleaners should do fine. I don't like to use the standard coil cleaner products for this, as most of them are acidic, and while they would be fine in a large house air conditioner, I don't like the idea of these products running down the outside of an RV.