cleaning fins

Hope this is the right forum for this.
I usually clean the fins on our air cooled chiller about once a week using a garden hose during the warmer part of the year. My question is... Is there an outdoor temperature that would be to cold when it would be wise not to wash them due to possible freezing or any other damage to the unit?

No, providing you don't spray anything electrical you should be OK.

Once a week sounds a bit excessive but it will depend on how dirty your air is I guess and during the winter your chiller will cope with a bit of dirt on the coils.

My biggest concern would be how the coils are cleaned. The tubes are staggered in the coil banks, so if is difficult to get these clean with only a simple spray.

More often than not I see the dirt "pushed" into coils by the water, rather than cleaned. My favorite method for cleaning air-cooled condensers was to use some of the foaming coil cleaner. You spray it into the coil at angles so that the liquid gets down into the coil. After a little while, the liquid turns to foam (about like shaving cream in an aerosol can). The foam pushes all of the dirt out, which is then easily sprayed off with a water hose. You also have to be sure to completely flush the coil bank with clean water to get ALL of the dirt out.

Once a year doing this should be sufficient, unless the area where the condenser sits is very dirty.

I have cleaned larger condensers that took an entire day to get clean, so do NOT get in a hurry. It's a messy job for sure!:D

Thanks for the response guys..
The chiller is outside in a grassy, tree and dirt path area, on a concrete pad, and on dry windy days alot of dirt is blown around. That is why I try to hit it once a week. I spend about an hour hosing it down. I do use the foam cleaner in the spring when the weather heats up. I was just wondering about outdoor temperature during the colder part of the year.
I would say most of the dirt tends to accumulate during the warmer part of the year, so I guess I should hold up during the winter as I have been doing in the past.

Air cooled condensers is better cleaned with with air pressure or nitrogen pressure or vacuum it to rmove the dust.
If it is cleaned with water it is improtant to dry so that any dust does not get cemented too fins.