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Topic: roof treatment around airconditioners (Read 507 times) previous topic - next topic

roof treatment around airconditioners

Washed , resealed and waxed my roof this week. I used Meguire's  clean and wax. NO cracks or surprises anywhere. The Dicor self leveling sealant worked well. My only question is the airconditioners.  I really can't get under them to reseal anything. Any thoughts of what I should do? No leaks inside the coach. Leave them alone?
Thanks
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: roof treatment around airconditioners

Reply #1 –
There is a  foam gasket around the A/C opening.  Do NOT caulk or otherwise try to seal it.

If it leaks from rain (i.e. around seal vs from condensate) you can try to further compress the gasket (4 bolts accessible from inside the coach).  But, the gasket is designed to only be compressed about 50%.  Gaskets are not expensive and other than the roof unit being bulky, not hard to replace.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: roof treatment around airconditioners

Reply #2 –
Oh, good. Thanks for that. Now I know
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: roof treatment around airconditioners

Reply #3 –
I just put 2 new atwood ac units up top. The ATWOOD instructions call for a torque of 60 inch pounds.
92 Grand Villa
Silver 6v92
 side isle.
build# 3973

Re: roof treatment around airconditioners

Reply #4 –
Yup, some A/C units call for a certain torque, others for torquing until gasket compresses to half its original height.

And remember that 60  INCH lbs ain't much-- 5 ft lbs
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: roof treatment around airconditioners

Reply #5 –
Quote from: wolfe10 –
Yup, some A/C units call for a certain torque, others for torquing until gasket compresses to half its original height.

And remember that 60  INCH lbs ain't much-- 5 ft lbs
Yes but it can take a lot of turning to compress the gasket to that level on a new install. When I removed the old AC units all the bolts were loose.
'99 U320 40 WTFE
Build #5462,
1500 Watts Solar 600 amp Victron lithium
2012 Jeep Grand Cherokee Overland Hemi
Instagram bobfnbw
Retired

Re: roof treatment around airconditioners

Reply #6 –
Quote from: Bob and Julie –
Yes but it can take a lot of turning to compress the gasket to that level on a new install. When I removed the old AC units all the bolts were loose.

This is a very common place for a roof water leak, from loose A/C mounting bolts.  So much so that the dealer I worked for, as part of the the delivery inspection, on every used unit checked and tightened these bolts.    Overtightened bolts also can cause a leak so listen to wolf10 to torque or go to 50%.
97 U295 40, Build #5040, 6C8.3 325 HP
Oregon Continuous Traveler
Samsung Residential #RF20HFENBSR,
Xantrex SW2012, (3)AGM8D Hse, (2)AGM Grp24 Eng, Victron BMV-712, 1800w Solar 4 LG & 2 Sunpower
Extreme Full Body Pt w/hdlmps, new furn/floor, 4 down Lexus 2004 GX470 AWD curb weight 4,740 lbs
Prev: 1990 Barth, 10L 300 2 yrs; 91&92 Monaco Signature, 10 yrs, 10L C 300 &  6C8.3 300; 1997 ForeT 6C8.3 325 since May 2017.  Employed by Guaranty RV 14+ yrs.  Former VW New Car Dlr/Service Dlr, Sales Mgr, Rv Sales, and Service Adviser from 1968-2017
"Don't criticize what you can't understand" Bob Dylan

Re: roof treatment around airconditioners

Reply #7 –
So. You pull the inside covers off to access these 4 bolts or what? I better check them
Thanks
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: roof treatment around airconditioners

Reply #8 –
Quote from: dans96u295ft –
So. You pull the inside covers off to access these 4 bolts or what?
Thanks

YES.  Depending on make and model access can be a little different.

Let us know what make and model you have and we can likely give info specific to yours.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: roof treatment around airconditioners

Reply #9 –
I'll get the model on air
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.

Re: roof treatment around airconditioners

Reply #10 –
600 Penguin series. I pulled the vents and FT only bolted the fronts down. It appears the back two bolts are left out and the unit has  some sort of glue on the rear instead of securing bolts. The front two bolts were good and snug on both units.
1996 U295-36, Cummins 300hp, 8.3. Build number 4864. Vin number 1F97D536XTNO54271. Purchased October 31, 2019.