Roof A/C maintenance

Furnace, air conditioning, thermostats, distribution.
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chuckster
Posts: 56
Joined: Thu Aug 27, 2020 4:53 pm
Location: Meridian, ID

Roof A/C maintenance

Post by chuckster »

Hello Safarifriends,

Having recently purchased my '01 Zanzi 3646 I will probably pester the group with some questions for awhile. :lol:

I am interested in doing some preventive maintenance on the two Dometic roof airs in the coach and aside from obviously cleaning the grill and filter inside the coach want to perform some other routine maintenance up top. I have seen suggestions to use Nu-Calgon 4171-75 Evap Foam No Rinse Evaporator Coil Cleaner, let soak for a bit and then rinse with a spray bottle with water. Furthermore, it was suggested to lightly lube the fan shaft with 3-in-1 oil. Seems like that is pretty much "it" in a nutshell?

Do you ever need to have these roof airs recharged with refrigerant? I would think as long as you have cold air that it isn't leaking so never necessary?

Tips, tricks, do's, dont's?

Regards,
Chuck in Meridian, ID
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
Owner since 8/2020

wolfe10
Posts: 83
Joined: Sun Oct 27, 2019 4:12 pm

Re: Roof A/C maintenance

Post by wolfe10 »

Only change I would make is to use a light-viscosity non-detergent oil (like sewing machine oil), NOT 3-1 oil.

And, on the roof you will be cleaning both the condenser section (easy) and the evaporator section (more difficult but more critical because it effects quality of air going inside the coach). If the A/C has been operated in humid areas, it is not uncommon to find the fins of the evaporator black with dirt and mold!
Brett and Dianne Wolfe
Ex: 2003 Alpine 38'. Ex 1997 Safari Sahara. Ex 1993 Foretravel U240
Moderator, FMCA Forums 2009-2020
Chairman, FMCA Technical Advisory Committee 2011- 2020
Moderator, http://www.dieselrvclub.org/ (FMCA chapter) 2002-

chuckster
Posts: 56
Joined: Thu Aug 27, 2020 4:53 pm
Location: Meridian, ID

Re: Roof A/C maintenance

Post by chuckster »

Well, I got this done this past weekend to both roof airs. They were on the fairly dirty side but not real bad. I used the same products for cleaning the condenser and the evaporator as this gentleman did in this decent YouTube video. The pinpoint spray nozzle was VERY effective in getting in between the fins and not using a lot of water. In fact, there was negligible overspray where I had stuffed bath towels in the opening to insure no drips down into the coach and had towels below inside the coach underneath the A/C's to catch any drips.

The job was pretty easy overall. I used a fin comb/straightener to straighten some fins that were bent. I was able to get by with one can of evaporator cleaner for both A/C units but the condenser cleaner is a 'blaster' that runs out pretty quickly and requires one can per A/C unit.

Here are some links for those who want to do this themselves. There are several maint videos on Youtube.

RV A/C maint. video - https://www.youtube.com/watch?v=fv5KBhdEvNg

Nu Calgon 4290-75 18-ounce Nu-Blast Condenser Coil - https://www.amazon.com/gp/product/B00HW ... UTF8&psc=1
Nu-Calgon 4171-75 Evap Foam No Rinse Evaporator Coil Cleaner, 18 oz - https://www.amazon.com/gp/product/B00DM ... UTF8&psc=1
Heavy Duty Brass Garden Hose Shut Off Valve - https://www.amazon.com/gp/product/B01DC ... UTF8&psc=1
Little Big Shot Super Nozzle - https://www.amazon.com/gp/product/B0052 ... UTF8&psc=1
Primeswift FCR6 Fin Comb Tool Set for Straighten Evaporator Condensor Coils - https://www.amazon.com/gp/product/B07WB ... UTF8&psc=1

Thanks, good luck doing this yourself DIY's and stay cool!

Chuck
Chuck in Meridian, ID
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
Owner since 8/2020

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