VIAIR 380C to blow out water lines?

[Christo]

Does anyone use their airbag compressor (VIAIR 380C, 1.8 CFM) to blow out their water lines for winterizing?

Actually, I have a Superflow tire inflator that is rated at 2.5 CFM, so that would even be better. But is that enough flow?

I'm aware that the max pressure should be limited to about 40-50 PSI.

 

[LQQKatJon]

It wont really work. Blowing out waterlines is really about volume then pressure. I have used my viair to blow up pool floats and I do not believe it would blow out water lines well at all.

 

[tyler]

My coachman coach has more of a modern sensibility of drainable water lines with one or two low drain points. my GMC upfit has stuff up over the ceiling, wavy pipes behind counters, flat spots under sinks, etc. My air blow out approach is simply move enough volume to leave freeze expansion room for any leftover water - not really dry. I use the pink antifreeze to really consider it winterized. And even that got me once in the GMC system - I put pink in fresh water tank and pumped through out. Then the city water connection burst to teach me the 1.5 foot vertical spur from fresh line to city fill valve does not drain (unless you put some air through with an adapter). So to do pink, i have to originate from fresh tank AND city fill both. Don't forget drain water heater tank, and I have a water heater bypass to set. pink all the way out the macerator outlet to consider that protected. Shew, what we do for fun!

 

[Christo]

My coachman coach has more of a modern sensibility of drainable water lines with one or two low drain points. my GMC upfit has stuff up over the ceiling, wavy pipes behind counters, flat spots under sinks, etc. My air blow out approach is simply move enough volume to leave freeze expansion room for any leftover water - not really dry. I use the pink antifreeze to really consider it winterized. And even that got me once in the GMC system - I put pink in fresh water tank and pumped through out. Then the city water connection burst to teach me the 1.5 foot vertical spur from fresh line to city fill valve does not drain (unless you put some air through with an adapter). So to do pink, i have to originate from fresh tank AND city fill both. Don't forget drain water heater tank, and I have a water heater bypass to set. pink all the way out the macerator outlet to consider that protected. Shew, what we do for fun!

Unfortunately don’t have a water heater bypass

 

[RJW]

I always use propylene glycol when I winterize my motorhome. I always thought that, while more expensive, it was a was a better way to winterize. Less foaming and less after taste in the spring. It's more expensive and harder to find. I recently purchased 10 gallons (I only use about 2 each winterizing) from Menards.

I asked AI about that and this is the response which validates my choice:

When it comes to the "pink stuff," the choice between alcohol (ethanol) and glycol (propylene glycol) is one of the most debated topics in the RV community. While both will prevent your pipes from bursting, propylene glycol is generally considered the superior choice for the health of your RV.

Here is the breakdown of why one is usually preferred over the other.
1. Propylene Glycol (The "Premium" Pink)

This is the gold standard for RV winterization. It is a food-grade, non-toxic antifreeze that is actually used in some food production.

Pros:

Lubricates Seals: It acts as a lubricant, keeping your rubber seals, O-rings, and water pump impellers soft and pliable throughout the winter.

Better Taste/Odor: It is much easier to flush out in the spring and rarely leaves a lingering "chemical" taste in your fresh water lines.

Non-Flammable: It is completely safe to store and use near potential heat sources.

• Cons:
  • Cost: It typically costs 2–3 times more than alcohol-based versions (often $15–$25 per gallon vs. $5–$8).
  • Harder to Find: You often have to look for it at dedicated RV dealerships or specialty stores; big-box stores usually carry the cheaper blends.

2. Ethanol/Alcohol (The "Budget" Pink)​

This is the most common type found at places like Walmart or hardware stores. It uses ethanol (alcohol) as the primary freeze-preventative.

• Pros:
  • Inexpensive: If you have a large rig and need 5+ gallons, the cost savings are significant.
  • Widely Available: You can find it almost anywhere.
• Cons:
  • Dries Out Seals: Over time, alcohol can dry out the rubber components in your faucets, toilet valves, and pump, leading to leaks in the spring.
    

    Which one should you choose?​

    If you...	Use This Type
    Want to protect your seals and avoid a bad taste in spring	Propylene Glycol
    Are on a strict budget or only using it for P-traps/drains	Ethanol (Alcohol)
    Live in an extremely cold climate (below -50°F)	Propylene Glycol (Higher concentrations are available)

    
    

 

[tyler]

Unfortunately don’t have a water heater bypass

$21 Camco kit at retailers - well worth it. my bypass leaks with pressure, but there is no pressure on it when winterized. It was too awkward/upside down to get at it and get it leak free with that fact in mind

 

[tmsnyder]

I blew out my lines with the viair compressor this year, worked fine but I wasn't looking for 100% clear conditions. I do have a hot water bypass. Then I pumped pink antifreeze in until it came out each line.

 

[Christo]

I blew out my lines with the viair compressor this year, worked fine but I wasn't looking for 100% clear conditions. I do have a hot water bypass. Then I pumped pink antifreeze in until it came out each line.

Not sure of the advantage of blowing out the lines if you're going to run antifreeze anyhow

 

[Richard RV]

Not sure of the advantage of blowing out the lines if you're going to run antifreeze anyhow

From the viewpoint of the compressor everything needs a good blow.

 

[TR 1]

If you have a low volume, high pressure source, one option would be to pressurize the system and then release the pressure suddenly. This "blow off" action moves a high volume of air in a short time.

I haven't tried this technique with an RV, but have used it when purging flush chemicals from an AC system. Usually do it a few times, which pushes any fluid towards the outlet. After a few repeats, the "blow off" is fairly dry. Would think a modified technique could be used for the water system. Not sure what is stock on a GMC, but my coach does have ball valve drains, which would help the process. Obviously you'd also need to be careful with the pressure...