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.