What is acceptable approach (trade, residential HVAC) to clean condenser coils on outdoor unit.

[Reader90]

Hello,

Background: As part of a neighborhood dispute between two neighbors related to replacing a brick/block wall between two home owner properties. The work to demolish about 30 feet of a 6 ft tall retaining brick/stucco wall had already started. All of this material has been removed. The project was stopped by one of the homeowners due to the claim the work is impacting their equipment (pool equipment, home, irrigation and HVAC equipment on their side of the property. Without going into all of the details, an assessment was done for all of this equipment and area by different trade personnel (pool, irrigation, HVAC). All equipment is working, but there were two items identified by the HVAC company. #1 comment below perplexed me.

1. "property A/C coil cleaned by licensed A/C company (Do not use water)".
2. Any rock/debris should be removed at bottom and around the HAVC condenser units.

Not concerned about #2, as this is a simple remediation. However, can anyone here comment, high level, what is "best practice" or "commercially reasonable" approach for the comment within #1? The coils have no obstructions (leaves, dirt) lodged within the coils. I have seen basically two ways HVAC companies have performed this type of maintenance.

1. Using a garden hose, spray water, taking care not to use too much pressure, and move water from hose up/down and left/right through the protective case or housing of the HVAC condenser units.
2. Use method #1, but first apply a foam based spray, leave applied on coils for 15 to 20 minutes, and then remove by spraying water (using typical garden hose city water)
NOTE: I assume if the there was lots of debris and/or units were really dirty, one should take off condenser protective housing to allow a more thorough cleaning.

I probably left off some things like, disconnect AC power, avoid spraying water or chemical (if used) in electrical/wiring areas.

How can this task be done realistically without water?

Thanks in advance!!

 

[Fitter30]

The only i use coil.cleaner is when the customer insists or grease or oil is on the coil. Have seen to many coils lose their fin strength after a few cleanings. If the coil looks like a porcupine has to be cleaned with low pressure washing. High efficient units may have a double coil that has to be split and cleaned with water. Unit that has brick and mortar debris first vacuum then wash. If fins are in good condition and single row used co2 with a drum adaptor, safety glass and ear plugs. Have to be careful not to bend the fins ( starts out 1000 psi but drop off as drum gets cold) unit can be running and all the dirt will blow out the top. Washing with water no pressure washer, power off. Wash inside out if possible watch bending fins.

 

[Sponsor]

 

[John Gayewski]

I think they use a mixture of water and concentrated coil cleaner nowadays. When they say don't use water they don't mean 0 water. They mean a mixture. They used to spray the coil cleaner then let it sit then water. But I think there may be an inhibitor mixed in with the second part now.

 

[Sylvan]

I think they use a mixture of water and concentrated coil cleaner nowadays. When they say don't use water they don't mean 0 water. They mean a mixture. They used to spray the coil cleaner then let it sit then water. But I think there may be an inhibitor mixed in with the second part now.

When I was a stationary engineer (prior to being a master plumber) we did use water and chemicals mostly degreaser agents

The worst one I ever encounted was in Manhattan China town area where the exhaust from the Chinese restaurant that caused the coils to be encrusted with 1/2" of grease and bird feathers.

We used a 1,200 PSI pressure washer

 

[Reader90]

Thanks for the input. These are very old units, ~1996 or so. The units are in "good shape", i.e. no observed coil damage or debris. There is evidence of water hardness (calcium) which can be seen on the outside of unit and other areas next to condenser units caused by irrigation spray. Personally, this is somewhat of a bogus demand, due to age of units and suspicion of lack of cleaning based on irrigation overspray.

Okay. I have asked the A/C company directly that supplied the pre-testing and write-up to clarify how exactly "property A/C coil cleaned by licensed A/C company (Do not use water)" would be done -- by them, at what cost. I have reached out to a few other firms asking for cost and general approach they would take to perform task, but not expecting a decent response that the latter question.

My take away here then is:

1. Consider compressed air or some type of forced air to start, as needed.
2. Consider vacuuming/cleaning out inside bottom the condenser units, as applicable.
3. Consider, but be cautious, with use of any cleaner chemicals that are used in the process.
4. Use low pressure water stream at coils, preferably from inside, towards outside..

 

[John Gayewski]

Thanks for the input. These are very old units, ~1996 or so. The units are in "good shape", i.e. no observed coil damage or debris. There is evidence of water hardness (calcium) which can be seen on the outside of unit and other areas next to condenser units caused by irrigation spray. Personally, this is somewhat of a bogus demand, due to age of units and suspicion of lack of cleaning based on irrigation overspray.

Okay. I have asked the A/C company directly that supplied the pre-testing and write-up to clarify how exactly "property A/C coil cleaned by licensed A/C company (Do not use water)" would be done -- by them, at what cost. I have reached out to a few other firms asking for cost and general approach they would take to perform task, but not expecting a decent response that the latter question.

My take away here then is:

1. Consider compressed air or some type of forced air to start, as needed.
2. Consider vacuuming/cleaning out inside bottom the condenser units, as applicable.
3. Consider, but be cautious, with use of any cleaner chemicals that are used in the process.
4. Use low pressure water stream at coils, preferably from inside, towards outside..

I'm not sure how you came to those conclusions.

 

[Reader90]

I'm not sure how you came to those conclusions.

Not following your comment, but I think I have what I need to be knowledgeable enough when talking to an HVAC contractor for the task. Thanks again for the input!