Thick HVAC coils are a challenge to clean. The problem is that you might not know you have a problem.
That’s because a brief cleaning can make a coil bed look good from the outside. A quick blast from a pressure washer rinses off the outer layers, but deep inside sludge and residue buildup could be straining the system. Sometimes system inefficiency is mistaken as a sign that the system needs to be replaced. It might just need a good cleaning.
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A high pressure cleaning system is not a good choice, for two reasons.
Number One: If you err too high on the water pressure, you risk damaging the coil bed’s delicate fins. We’ve seen some pretty wild photos of the damage that over-vigorous pressure washing has done to coil fins. You don’t want to be doing that.
Number Two: While a high pressure unit might clean the first inch of the coil bed well, it may not clean deeper than that. It blasts away dirt at the outer edges of the coils, but the water pressure drops significantly as the flow penetrates farther into the bed, slowed by the coils in its way. The water pressure might just be enough to drive the dirt deep into the system and drop it there, but not enough to completely flush it out. Now the dirt is out of sight, but harder than ever to remove.
And if a corrosive cleaning agent was used, traces of it might be left in the sludge. Now you have harsh cleaner residue deposited on the coil bed, slowly promoting rust and pitting – not a pretty picture.
Fortunately, there’s a better way. A best way, in fact. A low pressure, high volume approach to coil cleaning is the way to go with thick coil beds. Here’s why.
You clean coils with a combination of water volume and water pressure, which varies somewhat inversely to one another. So a high pressure system puts out a smaller volume of water. But it loses a significant amount of its pressure as it penetrates farther into the bed, and now it has neither pressure nor volume going for it.
A lower pressure, high volume water flush has the power to loosen and dislodge caked-in dirt and cleaning residues. The high volume of water flowing through the system keeps up the attack on dirt and sludge. There’s nothing like the relentless power of water to move soil in nature. The same action works in your coil bed.
SpeedClean’s FlowJet Coil Cleaner System delivers the pressure you need and a water flow rate to power through even the dirtiest, thickest coils. Its 400 psi spray powers through coils up to 6’ thick, yet it won’t damage fins. The heavy, 2.5 GPM flow flushes out dirt hiding deep in the coil bed.
It’s portable and compact, making it a great choice for rooftop AC units, and it easily handles commercial evaporator units, thick refrigeration coils and microchannel coils. Look at our optional attachments for hard-to-reach coils and for cleaning from the inside out, forcing dirt and debris back out the way it came in.
Be sure to add SpeedyFoam, our non-caustic and biodegradable coil cleaning solution, or BBJ’s Power Coil Clean. They clean effectively while going easy on both your crew and the environment.
Just wondering if this system will work on large air handler 12″ coils? We are trying to clean a AHU coil that had been treated with enzymatic cleaner and the result was a huge pressure drop. We’ve used a probiotic treatment which had no effect on the pressure drop. I need some info and what kind of system or method to use since our 2.0 gpm 1400psi pressure washer didn’t do the trick. Please let me know, thanks!
Those are some thick coils! The key is water volume, not pressure. That pressure washer isn’t putting out 2.0 GPM when you have to stand back so you don’t blow coils apart with the 1400 psi. Our FlowJet puts out 400 PSI at 3.00 GPM so you can get right on those coils. Even that may not be enough, but perhaps if you use our extension wands to get in front and back of the coils it can help dislodge any debris and buildup. Use a good non acid foaming coil cleaner too and let it sit for a while. Good luck.
I have been using multi-enzymes for the past 20 years and never had a problem with breaking down bio-films at 12 inch thick coils. Obviously, it has to be flushed from the air-on and air-off side for effectiveness. High pressure jets may be used if the fins are in good condition. Like what Tim has mentioned, volume of water and pressure will do the trick. Having said that, if the coils are brittle and oxidised, pressure jets must not be used. Enzyme solutions are the best for such a scenario, where volumes of water is able to dislodge the debris internally.
Per the first comment: will using the flow jet eliminate the need to split the coils?
So, if I were to use the Flowjet coil cleaning system, and the proper attachments, I would no longer need to Split the Evaporator coils to get them clean? Is this a correct assumption?
Will the drain system handle 2.5 gpm?
How can we prevent splashing or spillage in situations that would result in water damage?
Also, the coil should be back washed (in the direction opposite to the airflow.
The Flowjet is designed for use outside, cleaning condenser coils, not inside. So 2.5 GPM isn’t an issue. And yes, the coil should preferably be cleaned opposite the air flow. We offer a variety of attachments to help do that.