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Air in Oasis lines

I recently had MOT bleed a bunch of air out of the Oasis lines.  The problem is that I don't know how the air got into the lines and MOT didn't have a lot of ideas either.  They speculated that the relief stuck & some of the boiler fluid might have boiled off.  Oasis is functioning fine & was working with air in the lines ... just lots of gurgling noises as it circulated the fluid.

I did winterize it a month ago in prep for a service at Cummins.  I blew the water lines out with air.  But I regulated it to 20 psi & used a high pressure fitting consisting of a rubber grommet and duct tape.  I don't see how that could have forced air into the Oasis ... but maybe there is a route I don't see. 

This coach did have some freezing damage before I bought it.  Could there be a very slight leak between the water/boiler systems that doesn't show up under normal conditions?

Appreciate some help & ideas so I don't get a repeat next year.
Dave Carpenter
2011 Nimbus 42 ft
2009 Nimbus 38ft
2017 Wrangler Toad

Re: Air in Oasis lines

Reply #1 –
Dave,  You might call International Thermal Research, Oasis manufacturer and ask about blowing the fresh water lines out to winterize them.  36 zero  99 three  4877  I have not asked them regarding blowing out the lines.

You can NOT blow out the Aqua Hot fresh water lines.  They will freeze, split and require a new heater to fix, big bucks.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Air in Oasis lines

Reply #2 –
Rudy, I've thought a lot about why an Aquahot cannot be effectively blown out with compressed air.  There's no question that it's possible to put enough air through it to remove the water that's in the coils.  Is the concern that condensation will develop and settle in the low part of the coils?
George Mann
2002 U320 #5934
2017 Rubicon
2013 BMW GS
Waterford MI

Re: Air in Oasis lines

Reply #3 –
Quote from: Geodmann –
Rudy, I've thought a lot about why an Aquahot cannot be effectively blown out with compressed air.  There's no question that it's possible to put enough air through it to remove the water that's in the coils.  Is the concern that condensation will develop and settle in the low part of the coils?
  How do you know you got all of the water out of the low spots without running a pig through the line to force the water out?  With out running a pig through the lines,  you will find out you did not get all of the water out is when you try to use it again.  Then you get to call Rudy or one of the other dealers and cost  you a few coach bucks.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Air in Oasis lines

Reply #4 –
On the other hand has anyone tested their RV antifreeze by placing a sample in the freezer?  I did and it freezes into a slush but with enough force to expand the lid of a Mason jar.  That's a little worrisome.  I do believe that 80 psi air blowing through the relatively small diameter copper tubing coils until it comes out without water droplets is sufficient to prove that any remaining water vapor would not pose a freezing hazard..... Unless condensation is the concern.  Irrigation systems are winterized this way, they commonly have trace amounts of water left behind yet they rarely freeze and split if done properly.  Just thinking out loud here.
George Mann
2002 U320 #5934
2017 Rubicon
2013 BMW GS
Waterford MI

Re: Air in Oasis lines

Reply #5 –
When you blow air through the coils the air bypasses some of the water on the uphill parts of the coils and drops back to the bottom after the air is stopped and will fill the tubes there. That is where the water will freeze and split the tubes.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Air in Oasis lines

Reply #6 –
Why would you want to take a 10,000 dollar experiment? When it has been proven many times by others that blowing out the aqua hot will lead to broken hot water loop. Do what makes you happy.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Air in Oasis lines

Reply #7 –
I don't think 80 pounds of air will clean the tubes.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Air in Oasis lines

Reply #8 –
Quote from: Geodmann –
On the other hand has anyone tested their RV antifreeze by placing a sample in the freezer?  I did and it freezes into a slush but with enough force to expand the lid of a Mason jar.  That's a little worrisome. 

I remember reading about this somewhere.  I was concerned when I read about it starting to freeze up.  My mind is starting to go south on me but I believe in that same thread there was a good explanation as to what was going on and I felt safe using it. Let me qualify the above that I live in Houston and I have never winterized any of my toys (or anything) except for last year in the big Texas deep freeze.

While I am thinking about it. In the example above it was in a closed jar.  I wonder if the glass would break if test was done with two jars, 1 with AF  and other with water. Both with no lids.  Will the one with only water break the glass when it freezes?  That would be the same as water being in a  copper line.


2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago
 

Re: Air in Oasis lines

Reply #9 –
I think most of my fellow foretravel owners that live in Canada would agree that the only way to truly get the water out of the coils is to winterize with pink. I have routinely experienced temp of -22 F and below with NO damage to any lines, let alone the AH coils. Why take the chance with blowing lines except for the less time it takes?!
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox