New blow-out shutoff valve

Wayne

Wayne

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Staff member
I finally got around to making a shutoff valve to go inline from the air compressor line to the trailer, so I can shut off and regulate the air at the trailer. I don't have a regulator on this line so I needed a valve near the trailer so I could control the rate the air flow, which allows me to control the pressure if I always leave at least one of the faucets open. I would put a regulator at the trailer, but there is 100' of 3/8" air hose and I'll lose so much volume with a regulator that I can't use one. This is the next best method to control the pressure and it works well. I open a faucet, then open the line. The pressure stays in a safe zone because of the pressure drop in the 100' of air hose, but if I want to close all faucets, then I go outside and close the valve to avoid over pressuring the system.

I also used the valve inline today to blow out my sprinkler system, same idea to control the pressure and it works really well.

All components from Harbor Freight for about $20.

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Did you ever think about putting an oil trap on the setup? You wouldn't want to blow any atomized oil through the system, although with 100 feet of hose there really shouldn't be any by the time the air gets there.

Don't remember where I got mine from (likely Amazon) or if I truly need it. Seemed like a good idea at the time since I'm just using a cheapie HF oiled air compressor.

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That's probably a real good idea. I have a small compressor with a small tank and a 70 gallon reserve tank that stores most of the air. Both tanks are at least 20 years old and are probably pretty gross inside.
 
Wayne said:
That's probably a real good idea. I have a small compressor with a small tank and a 70 gallon reserve tank that stores most of the air. Both tanks are at least 20 years old and are probably pretty gross inside.
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Yea, I figure cheap insurance.
 
ever wonder if 100 psi of pneumatic pressure exerts the same physical stresses as 100 psi of hydraulic pressure?
 
MSCH said:
ever wonder if 100 psi of pneumatic pressure exerts the same physical stresses as 100 psi of hydraulic pressure?
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Static pressure yes, but since fluid isn't compressible you'll get higher pressure spikes in hydraulics.
 
Wayne said:
Static pressure yes, but since fluid isn't compressible you'll get higher pressure spikes in hydraulics.
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kind of what I figured..

you know the PEX tubing in RV's is surprisingly similar to the piping used in pneumatic systems on vehicles.
that stuff stands up to 150 psi or more..

wonder how much air pressure you could pump into a sealed RV water system before something would finally let loose?

Wonder what the pressure relief valve in the hot water system lets off at.. which should be the limit?
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maybe you dont even need a regulator or you could have just used a 3 way nipple
with a gage in it and used the gate valve as a throttle..?
 
MSCH said:
wonder how much air pressure you could pump into a sealed RV water system before something would finally let loose?
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I've been hooked up to a system in Moab that was 125 psi without any problems. That prompted me to have Amazon deliver a regulator to that RV park.

MSCH said:
Wonder what the pressure relief valve in the hot water system lets off at.. which should be the limit?
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I believe the relief is set to 150 psi.

MSCH said:
maybe you dont even need a regulator or you could have just used a 3 way nipple
with a gage in it and used the gate valve as a throttle..?
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I think a three way with a gage is a good idea...
 
Wayne said:
I've been hooked up to a system in Moab that was 125 psi without any problems. That prompted me to have Amazon deliver a regulator to that RV park.


I believe the relief is set to 150 psi.


I think a three way with a gage is a good idea...
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yeah, I have a few of those brass one setting water pressure regulators like this https://www.amazon.com/Hourleey-Hi-...55&mcid=10faf1d59e2a379fbf1267d2e35d1b58&th=1

my old man never once used anti freeze in any of the 6 RV's he owned. that stuff is a PITA to get out of the systems ..
only thing he did was drained the tanks and water heater in the Fall and used a short piece of garden hose with an air nipple in it and he opened all the water faucets and blew it out same way you are doing.

where you live, when do you usually go below freezing and stay that way?
 
Nice work Wayne!

FWIW, I stopped blowing my lines out a couple of years ago. It didn't matter how much I tried I always had water left over. Now I remove the low drain points and open all the faucets and let the water run out below. I then close the taps and re-cap the low point drains. I run the RV antifreeze through the system and place a bowl in the sinks to catch any water until the antifreeze runs bright pink. I use about 2-1/2 gallons by time I fill the drains as well.

Just my $0.02
 
MSCH said:
where you live, when do you usually go below freezing and stay that way?
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Yes. We had two nights last winter with lows at -22F and highs right around 0F. The average low is about 15F with the average high of about 40F
 
Wayne said:
Yes. We had two nights last winter with lows at -22F and highs right around 0F. The average low is about 15F with the average high of about 40F
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I was just wondering about when did your area generally expect's it's first hard freeze?
 
MSCH said:
I was just wondering about when did your area generally expect's it's first hard freeze?
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Oct 7th is our 50% probability average first frost and Oct 20th is our 90% probability average first frost. It's Oct 24 and we haven't had a frost yet, but the forecast says it will be about Nov 1.
 
Going under 30 tonight so I went over and blew the lines out. My blow-out valve isn't as fancy as yours, got on Amazon for $13. Don't really trust blowing out the lines, can't seem to get all the water out . We still have a short trip or 2 before it gets into the 20s then I'll put antifreeze in.
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Wayne said:
I added a pressure regulator to my modular shutoff valve. Guessing how much pressure is in the plumbing is not a good long term solution.

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Wayne, pretty good for a first design, obviously it will function as intended the way it is, but you can cut its size in half by eliminating the redundant fittings( the quick connect parts ). just use the gate valve with air inlet nipple on the supply side, install the regulator on the delivery side, use the 3/4 water hose fitting on the delivery side of the regulator. I bet you can actually regulate the air pressure just using the gate valve and just look at the gage on the regulator....
 
MSCH said:
Wayne, pretty good for a first design, obviously it will function as intended the way it is, but you can cut its size in half by eliminating the redundant fittings( the quick connect parts ). just use the gate valve with air inlet nipple on the supply side, install the regulator on the delivery side, use the 3/4 water hose fitting on the delivery side of the regulator. I bet you can actually regulate the air pressure just using the gate valve and just look at the gage on the regulator....
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I could take the quick couplers out, but I want to be able to use each section independent of each other.
 
Coalescing air compressor filter is made to take oil out. They change color to let you know when to change them. Since the hose the has been used filter should be the last before the hookup to rv.
 
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