Cheaped Out on the Compressor : /

[bcheever]

Was getting ready to winterize my Caravel 22FB and had gotten tired of borrowing a friends compressor every year.

I went to Harbor Freight and bought a cheap pancake compressor - 0.6 SCFM/1/3 HP - and the poor thing can not hold enough pressure when the blowing the lines. The pressure goes to zero after 2 to 3 minutes blowing a line at 50psi.

If I get another compressor what's the minimum SCFM I should be shopping for? Or is there something I'm doing wrong that I'm not thinking of?

Thank you Airstream Community!

[SSquared]

I have a bigger portable compressor--I think it's 1HP with a 7.5 or 10 gallon cylindrical tank. And it still can't keep up. I'm OK with that, I just pause several times during the process to let it refill the air tank.

[SeeMore]

Check YouTube to learn a variety of compressed air techniques for winterizing your lines. One commonly held viewpoint is having a minimum cfm capacity to achieve the desired results. I believe that threshold number hovers around 4 cfm for continuous pressure versus the pulse cycle technique SSquared mentioned. I've been successful with as small as a 2.6 cfm pancake unit by draining everything first and then pausing between bursts (to refill the tank) to ensure low collection spots get pushed along.

[majorairhead]

I bought this little puppy a couple years back, it does everything I need it to do around my place

https://www.homedepot.com/p/RIDGID-6...50HB/303379052

[BGClassic]

ViAir RV450. Buy once, cry once. Use it for tires, and for winterizing. Powered by the 12V truck battery, or off terminals in the battery box.

[Mollysdad]

Originally Posted by bcheever

the poor thing can not hold enough pressure when the blowing the lines. The pressure goes to zero after 2 to 3 minutes blowing a line at 50psi.

Just from a common sense viewpoint, if your compressor is running constantly, then the lines are already blown out, no?
I imagine water in the lines met with a wall of compressed air, and in the space of a few seconds the water runs away.
I imagine a blast, not a process.
(Of course, living in Florida, I never do this but...)

[Bill M.]

I do not know the minimum. I use a bigger home shop model and it works fine. I also know that all the little pancake compressors are not all made any where near equal. The HF you have sounds like a dud. If you can take it back do so. If you can not then maybe Goodwill? When I bought my pancake I found that the bottom ones at Walmart and HF had only 1/3 of the capacity of the more expensive ones that looked exactly the same. Got the Porter Cable at Lowes, I think, and it has been a fine little tool for tires and a small nail gun. I would use it for winterizing but I do have the bigger compressor that is always ready.

Good reminder. I probably need to get out and winterize today. I blow the lines and add pink stuff both so not as fussy about the lines.

[bcheever]

Originally Posted by Mollysdad

Just from a common sense viewpoint, if your compressor is running constantly, then the lines are already blown out, no?
I imagine water in the lines met with a wall of compressed air, and in the space of a few seconds the water runs away.
I imagine a blast, not a process.
(Of course, living in Florida, I never do this but...)

When you pressurize the lines and open the faucet there is an amount of water that rushes out right away. But then there is a fine mist of water, maybe a couple of teaspoons a minute, that come out for maybe 4-5 minutes after.

If you read Rich Luhr's book on Airstream maintenance he says the problem is if there's any water left in the lines, even drops, it can all make it's way to the lowest point in the system and still do damage. So I like to open the faucets and let them run air for a minute or two and try to get most of the water out, damp air is OK but not residual spraying of water.

Actually my cheap compressor runs out after about 30 seconds. So a job that should take 15-20 minutes is now like 90 minutes.

I just saw Home Depot rents air compressors that are around 2.6 cfsm. Next time I do this job (soon since we camp a lot in the winter) I'll rent one and compare.

Appreciate all the great feedback!

[uncle_bob]

Hi

The real issue is CFM at what pressure level. The higher the pressure level they measure the CFM at, the more power it will take to get there. You have a limited amount of power from a standard wall plug. You have way less from a 12V cigarette plug.

If you are in a factory / commercial setting, you can hook up three phase power to the compressor and get to crazy combinations of CFM and pressure. The AS factory and service center have some really big compressors. That lets them go a bit crazy blowing out lines at some pretty high pressures.

Since most home compressors are set up for things like inflating tires, they are targeted at fairly high pressure / low CFM numbers. Finding one that is designed the other way around .... good luck ....

The "solution" is mentioned above, get one with a big tank on it. Let the compressor run for however long it takes to get the tank to max pressure. Then run the tank down *slowly* to flush out the lines. You don't need 180 pounds of pressure to do this. Anything over 30 pounds is probably plenty. A simple valve on the output of the compressor will help with this ....

Fun !!!

Bob

[RamRider]

I have the Ryobi version of this one : BAUER 20V Cordless 0-160 PSI Inflator from Harbor Freight- Its the perfect low pressure solution, I wire the trigger on and go through the AS blowing out each one of the lines (stool, sinks etc) and the out door shower, after draining the hot water tank. I finish by opening the low water lines under the AS

[Rosey Jet]

I have a “bomb” auxiliary tank that I hook up in series to my pancake compressor and it works great. Has come in handy several times. They are very affordable.

[CRH]

I use a cheap 6 gallon Campbell Hausfeld pancake. I set the regulator to about 40 psi and just let it run. I only open one faucet at a time. I can always hear air coming out. When blowing the lines out, I open a valve faucet and let it blow 5 or 10 minutes before opening another one. I repeat the cycle a few times. The compressor may run an hour straight. Probably not good for the compressor, but it was cheap and easly replaceable.

[BillfromWI]

I think your Harbor Freight compressor will do the job for you. But it will take a little longer. I usually use a Bostich 3.7 CFM at 40 PSI. But I have winterized on the road with a VIAR 450P-RV--not cheap and not big either. The method I use is attached.

Good luck!

[richard5933]

Originally Posted by Mollysdad

Just from a common sense viewpoint, if your compressor is running constantly, then the lines are already blown out, no?
I imagine water in the lines met with a wall of compressed air, and in the space of a few seconds the water runs away.
I imagine a blast, not a process.
(Of course, living in Florida, I never do this but...)

A too-small compressor won't have enough initial burst capacity to send lots of air through the lines all at once. Sending it through at a slower flow rate will cause the compressor to keep running but never actually clear the water from the lines.

Originally Posted by Rosey Jet

I have a “bomb” auxiliary tank that I hook up in series to my pancake compressor and it works great. Has come in handy several times. They are very affordable.

I think that this is the secret to using a small compressor - having an auxiliary tank which can provide a large initial burst of air. The pressure doesn't have to be (nor should it be) very high - it's the huge mass of air flowing through the lines that you're after.

Also, on some of the smaller pancake compressors they use a 1/4" line. That will only carry so much air. A 3/8" line will move much more air. A small compressor with a 1/4" line can be used to slowly fill the auxiliary tank, and by using a 3/8" line from that tank to the plumbing connection it would be possible to burst the air through the lines.

Or, just pump the pink stuff through the plumbing and call it done. Lots cheaper and quicker in my experience having done both.

[uncle_bob]

Hi

Ok, the "most fun" approach:

1) Blow out the lines with whatever compressor you happen to have. You are *not* trying to get every drop out, you only want to move out the large volume of water that's in the lines (and the hot water heater tank).

2) Bypass the water heater and pump the pink stuff through all the lines. You want a nice flow of fluid (not just foam and bursts of air) out of each faucet.

3) Hook up the compressor again and blow out all the anti-freeze you can.

Why do it this way?

1) You have to use a compressor to empty the fresh water feed line (the pink stuff won't get back there. You also need to blow out the black tank flush line. Since the compressor is hooked up anyway .... might as well blow the rest of things out.

2) Blowing out the excess pink stuff means there is a lot less of it to deal with in the spring. Flush out is *much* faster as a result. Again, the compressor is right there. Might as well use it.

3) As long as all that's left in the pipes is antifreeze, you are fine. There won't be any damage. Indeed, *less* antifreeze is actually less likely to give you problems. (Ok, how cheap did you go on the anti-freeze .... hmmm .... ).

Yes, this is Airstream, not every van, trailer, year, model works the same way. Any "generic" approach will have issues when you try to apply it to all of them.

Fun !!

Bob

[Mollysdad]

Originally Posted by Rosey Jet

I have a “bomb” auxiliary tank that I hook up in series to my pancake compressor and it works great. Has come in handy several times. They are very affordable.

Are you talking about the portable tanks that I see most places? Intended to be filled and then carried around?

[Dingo Girl]

We use a little hand held battery operated compressor for our 17 foot Caravel and it works great! We can winterize when we leave our boondock site the last time on the fall.
I can't imagine why your pancake compressor won't work for your little camper

[Bill M.]

Just a quick comparison if someone is still looking to buy a compressor to pump out lines:

.6 cf at 90psi, 110 max, 3 gallon tank, $70 HF.

2.6 cf at 90, 150 max, 6 gallon tank, $99 (Craftsman at Lowes)


Just for what it is worth

[Adiredneck]

If you want to do it right, it is a matter of volume, not pressure. Nine years ago I bought a Mi-T-M 20 gallon single stage electric compressor. Not cheap (now around $1400) as it is all made in USA. More than sufficient to blow out my 27FB Classic. I've also found, since I have a full-size garage compressor, that I've found many other uses for it - especially blowing all the chaff and debris off and out of my zero-turn after use.


IMPORTANT NOTE: Since this is an oil bath compressor, it is imperative that you put a particle filter and coalescing filter on the discharge line to remove any minuscule oil particles or vapors lest your potable water gain a sheen and a strange taste...





https://www.mitm.com/air-compressors/AM1-PE15-20M/1998/


Other photos on setup in my Gallery...

[Adiredneck]

Originally Posted by Rosey Jet

I have a “bomb” auxiliary tank that I hook up in series to my pancake compressor and it works great. Has come in handy several times. They are very affordable.

Be very careful using the portable tanks, as they have no pressure regulator on them.


I use a 7.5 gallon "Jegs" tank for filling tires, which I fill from my big compressor and I connect with a standard pneumatic hose and a Milton chuck that shows pressure in the tire; but I never use that tank for winterizing for two reasons:


1.) It is usually filled to 100 - 120 psi; way too much pressure to blow into your Airstream's water system. Never exceed 50 psi, which is what your water pressure regulator is set at. Higher pressures can blow joints and connections in a PEX plumbing system and cause leaks.


2.) 7.5 gallons isn't going to move much water out of your system. You need high volume at low pressure to do the job effectively.


I admit that I'm extremely cautious, and even flush with 5 gallons of pink antifreeze after blowing out the system; but my 2014 27FB Classic spends each winter in a pole barn at a county fairgrounds in northern New York State where lows of 20 below zero are possible, and a week or more with temps from 0 to -10F are usual. So far (knock on wood) I've had absolutely no freeze outs or leaks.