Cleaning a condensing unit

[summerblues]

is it sufficient to clean a condensing unit (with proper solution) from the outside or do I have to clean the coil from the inside as well ?

Ok people start laughing!

[BigJon3475]

Well think about what direction the unit pulls dirt into it.....Not to mention the leaves and crap in the bottom of the unit.

[summerblues]

so you are saying clean the inside as well, of course that's much more work, I was thinking that from the outside it may just well work into the inside and clean that as well. ?

[duckman373]

You have to pull the top, spray both sides with cleaner, and spray from the inside out.

[BigJon3475]

Never mind I see...we are in the same boat.....Yes clean from the inside out....Use a coil brush if you have one handy....

[summerblues]

No, I'm not a DIY,I'm certified. However this was a special situation were I had to install 5 - 10 seer units with older coils,I was worried that it may cause a problem , but so far so good.I still have to go back to adjust the charge because installation was done in the winter.

[BigJon3475]

No, I'm not a DIY,I'm certified. However this was a special situation were I had to install 5 - 10 seer units with older coils,I was worried that it may cause a problem , but so far so good.I still have to go back to adjust the charge because installation was done in the winter.

yeah I'm sorry dude I noticed after the fact...Me apartment maintenance also

[summerblues]

by the way, one reason I don't want to spray inside the unit is because even with the switch turned off there is still 120 to the unit, I have to go downstairs at the master panel to turn it off.

[BigJon3475]

Well then you would have to do that anyways....It's not recommended by me and probably not anyone to spray a unit down with power going to it. It really doesn't take that long...usually three wires for the condensing fan and several screws...It's your choice...do it the easy way and not be sure it's right or do it the longer way and be done with it.

[summerblues]

yes you are correct, the right way is always the best way, thanks

[d_griff]

i agree here,you should pull the condenser fan and spray from the inside out..you can see the crap your pushing out of the coil,i have way better results this way oppossed to just spraying the outside coil surface and washing

[BigJon3475]

Yup no prob...you can always clean out the crap in the bottom also and look for oil spots on the lines and anything else that looks like it shouldn't be there........

[Whale4]

I use one of those coil guns with the foaming wand, wash from inside out so It dosent get impacted works like a charm

[pecmsg]

by the way, one reason I don't want to spray inside the unit is because even with the switch turned off there is still 120 to the unit, I have to go downstairs at the master panel to turn it off.

That shouldn’t be.
Try correcting the code violations first.

5 10SEER condensers with older coils?

[johncavh]

what code violation

[BigJon3475]

power shutoff has to be within sight of the unit usually within at least 25 ft

[Shophound]

by the way, one reason I don't want to spray inside the unit is because even with the switch turned off there is still 120 to the unit, I have to go downstairs at the master panel to turn it off.

Check the disconnect near the unit. If it's a one armed bandit type, one of the disconnect knives/blades might be hanging up and not disconnecting both sides of line voltage. Nevertheless, any time you don't trust a disconnect switch, go for the breaker. You will do well any time you wash a condenser coil to ensure that all power is completely removed.

[techace79]

wow i have never pulled a disconnect and had one leg stay hot. at least i dont think. but i guess i would have known standing in all that water i just used.... that one is alittle weird for me

[BigJon3475]

Ive had one that was actually welded through and had to be replaced after a burnout on a pool pump..it was the pull out type not a throw switch...closest I have come.

[Shophound]

wow i have never pulled a disconnect and had one leg stay hot. at least i dont think. but i guess i would have known standing in all that water i just used.... that one is alittle weird for me

The springs that pull the knife blades out of the lugs can get weak over time and even break, leaving the knife firmly in the hot stuff. Had it happen to me on a roof with a three phase one armed bandit...and it was the stinger leg that didn't disconnect. More than one reason why it's called a "stinger" leg...

Also, sometimes a disconnect can be made and the knife arcs as it contacts its seat...the arc welds it to the lug and it will not come out again when the switch handle is moved to off. Always good to open a one armed bandit and check all blades for full disengagement before proceeding with VOM dummy checks inside the unit.

[summerblues]

The disconect is an ON/OFF switch, when you turn it off 120 is still running through it. 40 years old set up. Oh and it has thick alluminum wires from the cuircuit breaker that can sometimes corrode and turn to liquid. Nice !!

[Shophound]

The disconect is an ON/OFF switch, when you turn it off 120 is still running through it. 40 years old set up. Oh and it has thick alluminum wires from the cuircuit breaker that can sometimes corrode and turn to liquid. Nice !!

I've seen those kind of switches used at apartment complexes before. Cheap. In your case they are probably only breaking one side of the circuit, which may have been acceptable 40 years ago but no longer is.

Aluminum wiring was commonly used in the sixties/early seventies. I grew up in a neighborhood where many apartment complexes were built nearby using this wiring. We kids got used to looking up occasionally and seeing black smoke spreading across the sky, jumping on our bikes, and riding over to see the latest victim of aluminum wiring burn down.

Since you probably can't remove this wiring, the best thing to do is keep every connection it is made to TIGHT AND CLEAN. Use a protectant on the connections to keep corrosion in check. The biggest problem with aluminum wiring is the dissimilar metal expansion rates between wiring conductor and connection points. Over time these points work loose and create excessive heat. This is where most of the fires break out.

[BigJon3475]

http://www.inspect-ny.com/aluminum/aluminum.htm

You must use special procedures for Aluminum wiring

[johncavh]

yes i believe current code is within sight but have worked rooftop units with no disconnect installed. but the units are aprox 25 years old.