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MSHappyCampers · 12-05-2022, 10:37 AM

I was watching an old video from RV Geeks about winterizing an RV using air pressure. They showed using what looked like a standard adjustable water pressure regulator to limit the air pressure. Will that really work?

Alpine36 · 12-05-2022, 10:49 AM

I use the regulator on my air compressor set to about 50psi.
My hard plumbed in line water pressure regulator is set to 45psi and registers that when hooked up to air. That said I believe the water pressure regulator may actually regulate air pressure, but I wouldn’t trust it to be accurate. My suggestion is to regulate the incoming air pressure before the water pressure regulator….

Gary RVRoamer · 12-05-2022, 06:48 PM

It should, but most air compressors have built-in pressure regulators and there is no need for high pressure air anyway. A setting of 25-35 psi on the compressor is plenty, and compressors deliver greater air volume at lower pressures. It's the high volume of air that displaces the water, so a lower psi is better..

glwinger · 12-06-2022, 07:24 AM

Wondering if the density of water versus air makes a difference? Think about the pressure switch in the water pump, basically a pressure regulator. With water in the system, it turns off almost immediately when you close a faucet. With only air in the lines, it may never shut off.

TandW · 12-06-2022, 07:31 AM

With at least one tap or drain open and using a rubber tipped duster nozzle I find no need to worry about air pressure.

ga traveler · 12-06-2022, 07:42 AM

I started using air to winterize motorhomes in 1993. For 15 years I had only one failure. Someone had installed a ice maker in a closet in a 1987 allegro. We did not know it was there so the line to the ice maker was copper and froze.
We always used a regular water pressure regulator. They are just a spring and a seal working against the pressure. The regulator works just as well against air as water.
There are those against blowing out water lines. They claim it doesn’t work. That is just NOT true. Our lot always had between 65 and 120 motorhomes on it at any time. Trust me, my boss would have had my head on a platter if I had let a bunch of motorhomes freeze.

MoHoTripper · 12-06-2022, 08:55 AM

Quote:

Originally Posted by MSHappyCampers

I was watching an old video from RV Geeks about winterizing an RV using air pressure. They showed using what looked like a standard adjustable water pressure regulator to limit the air pressure. Will that really work?

When specifying a regulator you must consider the differential pressure from inlet to set point as well as the type of fluid. Water is not compressible, and air is compressible. So they require different regulator orfices and plugs.

Although the water regulator probably would work with air to reduce the pressure, you wouldnt be able to regulate very precisely or even at all.

As suggested by a few others, using the regulator on a compressor would be a better solution.

Donskiman · 12-06-2022, 09:52 AM

I use both a regular water pressure regulator and the regulator on my air compressor. I blow out all the lines 3 times with a short wait between blow outs. The first time blows out most of the water, the second gets a very small amount of residual water that pools back, the third just pushes out air to confirm all the water is gone. It takes a bit of time with 3 sinks, inside and outside showers, 2 toilets, water pump, water heater, washer/dryer, black tank flush line and line to the fresh water tank. We don't have an ice maker so no need there. Pink then goes in all the P-traps, toilets and run thru the washer pump. No pink in the water lines. Afterward, all faucets are left open, as well as low point drains. It got down to -20*F last year and it all went well.

US1 · 12-06-2022, 12:10 PM

For limiting pressure just to blow out open lines to winterize, use either the air compressor regulator or your water regulator. You are not building a rocket. No need to get out the slide ruler

DKRITTER · 12-07-2022, 11:25 AM

I use the regulator on the air compressor, never had an issue.

MSHappyCampers · 12-07-2022, 11:30 AM

I called The Water Filter Store yesterday and left a message asking them about this, but haven't heard from them yet.

Getting back to what someone said, it seems to me that as long as one faucet is open then it wouldn't matter how much pressure you use. What am I missing here?

ga traveler · 12-08-2022, 06:54 AM

Quote:

Originally Posted by MSHappyCampers

I called The Water Filter Store yesterday and left a message asking them about this, but haven't heard from them yet.

Getting back to what someone said, it seems to me that as long as one faucet is open then it wouldn't matter how much pressure you use. What am I missing here?

Most people are using a 3/8 in air hose. Most faucets have a “water saver” restrictor in them. It is a disc with a 1/8 hole in it. You are feeding in 3 times the air the restrictor can pass.
My compressor is set at 165 psi. That would be way to high.

US1 · 12-08-2022, 07:47 AM

Quote:

Originally Posted by MSHappyCampers

I called The Water Filter Store yesterday and left a message asking them about this, but haven't heard from them yet.

Getting back to what someone said, it seems to me that as long as one faucet is open then it wouldn't matter how much pressure you use. What am I missing here?

You are way overthinking this. Also, volume is what you want. Not pressure. Set pressure at 45-60 and blow them line out. Using the same air pressure as your water regulator insures you won’t blow apart a line. Your open faucet theory only applies to a compressor that can supply more volume than you can bleed off, at which point pressure can build up to high. Thus a regulator.

Most household compressors don’t fall in that area. With a faucet open, the compressor won’t shut once the tank has been depleted.
Close all the valves, let your compressor build up psi to 45-60, then open the faucets 1 at a time.

TandW · 12-08-2022, 08:04 AM

Quote:

Originally Posted by ga traveler

Most people are using a 3/8 in air hose. Most faucets have a “water saver” restrictor in them. It is a disc with a 1/8 hole in it. You are feeding in 3 times the air the restrictor can pass.
My compressor is set at 165 psi. That would be way to high.

Let me explain. I have a small compressor onboard that develops 80PSI. I carry a tire inflator with gauge and a rubber-tipped duster nozzle with a 1/8" tip. I have two coils of very lightweight plastic slinky-type air hose. When it is time to "Winterize", I simply fire up the compressor, open the appropriate valves, remove the water heater drain plug, and blow air throughout the system, opening and closing various valves to direct the airflow. The duster nozzle is merely inserted into the antifreeze pick-up tube at the water pump.
If I was using a 165# compressor I certainly would use a regulator to lower the pressure. But I see no reason to hard pipe a blow-out system for full air flow. The duster nozzle with rubber tip is more than adequate for admitting air at a safe rate. With at least one valve open, the pressure will never become destructive.