Cleaning Of Split Air Conditioners.

[vivid]

 

 

 

The Mckenic is just a like a normal floor cleaner kinda ingredients and concentration but in a ready-to-use pressurized spray can form.

   I have a floor/multipurpose cleaner sold over here that has the same active ingredient at the same concentration, akylbenzene sulfonic acid @ 5%.  The Quaternary Ammonium Compounds is also a cleaning agent, though at a low concentration, you'd find this in most floor cleaners as well.    What i mean by floor cleaners = the no-rinse ones that you'd mop the floor, 1 cap of the stuff into half a pail of water.

 

Used on its own (ie using the "natural" condensate to rinse the cleaner off, not even using any low pressure water spray from the mains), It would work for indoor FCUs that are relatively clean and regularly maintained.  That'd probably be like 2-4 weeks frequency for CM air.  And i certainly would not be surprised that if you do not have any HEPA filtration, you'd need to clean the indoor unit in just 1 week's time after the recent smoke episode with air quality hitting well over AQI 400 on a few days.

The external condenser coil would also benefit from a cleaning after the smoky season, which is like around now.

 

Anything longer than that, you'd need medium to high pressure water used in conjunction with such cleaners, really can't escape from that (of course as mentioned, you do not use a 4000 PSI diesel powered high flow rate unit with a 15 deg nozzle to blast it at 3 inches away).  There are other evaporator coil cleaners that have noticeably cleaning ability, but it still won't be like the alkaline coil cleaners.  However, alkaline coil cleaners isn't the optimum solution since you'd still screw up the aluminum coil even if you used it only once per year.  Once a year cleaning for the indoor FCU is pretty insufficient cleaning frequency for CM air quality if used daily even if you have zero allergies.

 

 

 

 

 

 

 

The floor/multipurpose cleaner that is being sold here

http://www.colgatecommercial.com/ColgateSite/media/MSDS/SDS Fabuloso Lavender_031918.pdf

 

[Dazinoz]

6 hours ago, vivid said:

BTW, i did measure my indoor FCU coil and outdoor condenser coil.  The external coil is around 2.5 to 3X the size of the indoor coil  (L x W x depth of the coils)....so in terms of heat exchanging performance, the external coil can stand up to more dirt and grime vs the indoor coil, and besides you also need to contend with indoor air quality with regards to the indoor coil, which is of zero issue with the outdoor coil.

I really don't think measuring the coils would give you an accurate indication of heat exchange as there are other variables such as fin surface area, tubing diameter, etc. You would have to look at the manufacturer's rating of each coil. From what I have read it seems like the condenser rating is around 20 to 25% bigger in actual heat transfer rating.

 

As well as taking heat from the inside some heat is produced during the compression of the refrigerant which needs to be dissipated. 

[Dazinoz]

6 hours ago, vivid said:

BTW, i did measure my indoor FCU coil and outdoor condenser coil.  The external coil is around 2.5 to 3X the size of the indoor coil  (L x W x depth of the coils)....so in terms of heat exchanging performance, the external coil can stand up to more dirt and grime vs the indoor coil, and besides you also need to contend with indoor air quality with regards to the indoor coil, which is of zero issue with the outdoor coil.

I really don't think measuring the coils would give you an accurate indication of heat exchange as there are other variables such as fin surface area, tubing diameter, etc. You would have to look at the manufacturer's rating of each coil. From what I have read it seems like the condenser rating is around 20 to 25% bigger in actual heat transfer rating.

 

As well as taking heat from the inside some heat is produced during the compression of the refrigerant which needs to be dissipated. 

[vivid]

2 hours ago, Dazinoz said:

I really don't think measuring the coils would give you an accurate indication of heat exchange as there are other variables such as fin surface area, tubing diameter, etc. You would have to look at the manufacturer's rating of each coil. From what I have read it seems like the condenser rating is around 20 to 25% bigger in actual heat transfer rating.

 

As well as taking heat from the inside some heat is produced during the compression of the refrigerant which needs to be dissipated. 

Quite interesting, thinking deeper.....you do have a point, the most accurate way of comparing them would be to compare the coil specs.  Unfortunately it's not listed on the AC model normal specifications.

 

The fin spacing distance between the condenser and evaporator coil seem to be pretty close though, i mean at least i don't see a physical difference of 3X.    I was told by the AC techs that the condenser coil is usually specified to handle way more heat transfer coz it's operating externally + without a pre-filter so it'd definitely get dirty at a faster rate, but by exactly how much they really don't know.  Maybe i shall do a google and see what i can dig out.  ????

 

 

Anyway, some good videos to share regarding why the condenser must also be cleaned in addition to the evap coil. 

 

 

Quote

Many technicians understand that a dirty condenser raises head pressure and makes the system more expensive to operate due to increased compression ratio, but do not realize that it has a direct effect on the sensible capacity (cooling that satisfies the thermostat). Heat goes one of two places when it is absorbed, into the ambient air, or back to the evaporator coil in the form of hot liquid traveling back to the metering device. This heat results in an increase in flash gas as the liquid is cooled down to the saturation temperature of the evaporator. An increase of flash gas results in a decrease of evaporator capacity, due to a decrease in temperature split. The system simply loses a large portion of its ability to cool. If the liquid line is warm enough that the temperature of the evaporator also rises, the latent capacity will decrease also. Watch and see the effects!

 

 

 

[vivid]

Measurements of the head pressure and current drawn by the compressor before and after cleaning by just high pressure water, nothing fancy.

 

Before = 90 PSI and 8.8A. 

After =  82 PSI and 8.2A. 

I also believe that after cleaning, the cooling capacity at the evaporator coil possibly could also have go up a little, due to more heat being rejected at the condenser.

 

The condenser coil isn't even really visibly dirty from the outside from a distance of 0.5m or so. I have seen wayyyy dirtier condenser coils around.

 

 

 

 

 

Another video demonstrating the drop in head pressure of the compressor.  The compressor was tripping (overload/overheat protection)
350 PSI -> 200 PSI after cleaing, that is a lot of pressure drop taking the load from the compressor!    Talk about system longevity of both pipes, joints and compressor.
27% AC current drop.
Same thing, it's not really visibly dirty from the outside.