Cleaning evaporator, rooftop units.

[atlantis]

Looking for a good way to clean evaportator coils in rooftop units, don't want to flood ductwork with water, it becomes very expesive to pay for damage, any ideas?

[brian9695]

It may seem crude but a toilet brush taped to a broom stick with some determination has usually worked. If its grease your trying to get off a coil, long nozzles and pressure sprayers full of coil cleaner. Best of luck.

[rtu]

Brush coil with stiff brush,
spray with green self rinse evap coil cleaner.
If that don't do it then cover the r/a opening
with sheetmetal or plexiglass that'll stop
the majority of the water from going into r/a
and if needed you can shopvac water out of basepan.
PITA to do but it works-

[sonc]

Steam works good

[acjourneyman]

Subbing it out to a duct cleaning company works the best for me.

[Irishmist]

ac journeyman: One question. When a subsequent problem develops with the coil, after the 'duct cleaning company' has done their thing, who has to make the warranty call; you or the duct cleaning company? If it's them, how well trained are they to perform hvac service? If it's you, how do offset the cost of running that call? Personally, I want to be the one responsible, not someone trained to access and/or perform service on the coil. Just curious. What I am afraid of is duct cleaning companies that pass themselves off as able to do 'service' on hvac equipment instead of the other way around. We do commercial duct cleaning through our mechanical contracting business, and that way there is no doubt whatsoever who is responsible. I must admit however, we have never entertained the idea of using our duct cleaning equipment on rtu coils. I will run this idea past the service manager. Thanks.

[acjourneyman]

Hi John, I usually service and repair chillers so do not work on RTU's very often.I have 1 building that has RTU's on it that I take care of and I do not want to clean the coils because they are open return with clothing merchandise below.They are a little dirty but customer at this time doesn't want to do them.I have never cleaned an indoor coil on an RTU nor have I ever had a duct cleaning company do it but it seems like a logical choice to me.

[whitepoundog]

Okay this is how I have done it in the past. This kind of job usually has to be quoted or sold, it is not usually done on a service call. I would have a drain pan made to fit right over the supply drop, with a helper and a wet vac handy we would powerwash the coils. sometimes the top of the unit needs to be removed or a small wand on a power washer. It would usually not take more than 4 hours to do even the biggest coil.But be very careful and try to tarp anything down below that you can. A pan costs under $50 just add it to the job.

[john dalton]

Dear Whitepoundog,

We work on a lot of field convertible units in the field such as Carrier and Rheem units and have found that removing the side return access panel and placing it in the return plenum opening under the units work great and reduce the need to have a return pan fabricated. We also like to use pressurized steam to clean and disinfect the evaporative coils, considerable less moisture, but getting the cleaning equipment to the roof can be a pain I must admit.

Respectfully Submitted,
John J. Dalton

[john dalton]

Dear Atlantis,

Ultimately the process of cleaning the evaporative coil will be a combination of methods depending on the age and condition of the coil, what is in the coil, how plugged it is, where the RTU is located, what is the access directly under the return, and a hose of other factors including the service technician’s experience and personal preferences.

Hopefully this has helped in your quest for information friend.

Respectfully Submitted,
John J. Dalton