Blew out the lines - did I miss anything?

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oldryder

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Nov 8, 2017
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Avon MN
Grand Design Camper. used 50psi to blow out each hot and cold line to faucets and shower. ALso water line to commode. removed plug from water heater. removed low point drains one at a time and blew those out with all faucet valves closed. poured RV antifreeze into sink drains to fill traps. drained all the tanks inc. very inconvenient fresh water tank dump valve.

did I miss anhything? We're back into freezing weather Friday.
 
I blew out my lines until I had a low spot in the line burst in my Class A. Replacing water lines in an RV is not fun. Now I always run RV antifreeze through the lines after blowing them out. Good cheap insurance.
 
TheBar said:
I blew out my lines until I had a low spot in the line burst in my Class A. Replacing water lines in an RV is not fun. Now I always run RV antifreeze through the lines after blowing them out. Good cheap insurance.
Click to expand...

Even blowing out the lines may let water settle in low spots. DON'T trust low point drains.
Another line often ovverlooked is the black tank flush.
Bar is correct, 15 minutes and a couple gallons of antifreeze.
Also, make sure you bypass the water heater.
 
I blew out like 10 times
But you did not mention the ice maker.. After the first blow out I'd cycle the ice maker so it drained back into the lines below. then Blow blow blow out like 10 times.

The key it to take time between each blow.
 
Did you remember the outside shower? I have forgotten that. I also blow out the lines and follow with pink stuff.
 
If you can blow all the antifreeze out of the lines, why can't you just blow all the water out of the lines in the first place. If you put 30-40# of air in the system and keep all the valves closed, opening only one at a time, making sure the compressor builds to the selected pressure before opening the valve, no water, none, can possibly remain in the system. Just keep closing and opening each valve while the pressure builds until no water, only air comes out. Make sure to clear the water pump, all the separate lines from the manifold, all the low point drains and the outside shower. I take the canister out of the water filter as well.
 
Onyrlef said:
If you can blow all the antifreeze out of the lines, why can't you just blow all the water out of the lines in the first place. If you put 30-40# of air in the system and keep all the valves closed, opening only one at a time, making sure the compressor builds to the selected pressure before opening the valve, no water, none, can possibly remain in the system. Just keep closing and opening each valve while the pressure builds until no water, only air comes out. Make sure to clear the water pump, all the separate lines from the manifold, all the low point drains and the outside shower. I take the canister out of the water filter as well.
Click to expand...
That is exactly how I blew out my lines for years in the same RV before it froze. My point of failure was a vertical pipe cut 1/4" too long pressing its horizontal line downward at that junction creating a low spot. The next identical RV off the assembly line may have been fine.

Another theory is it was 55 degrees and humid but it had been 28 the night before. The inside of the RV was still cold. Like a iced drink sweating on a warm day blowing warmer air through colder lines may have condensed water in the lines. I'm not going to advise people to cheap out to save $6. Then spend hundreds repairing the damage.
 
If you are trying to save money the cost of the antifreeze is very small compared to repairing a frozen line in the underbelly of a trailer or motorhome.

I always first blow out a much water as possible with air then completely fill the water system with antifreeze. Usually takes less than two gallons.
 
Samples of one notwithstanding, if you don't know how to use air pressure to clear the water lines you should defintely fill the lines with antifreeze, then later, completely blow the antifreeze out of the lines with air.
 
Onyrlef said:
If you can blow all the antifreeze out of the lines, why can't you just blow all the water out of the lines in the first place. If you put 30-40# of air in the system and keep all the valves closed, opening only one at a time, making sure the compressor builds to the selected pressure before opening the valve, no water, none, can possibly remain in the system. Just keep closing and opening each valve while the pressure builds until no water, only air comes out. Make sure to clear the water pump, all the separate lines from the manifold, all the low point drains and the outside shower. I take the canister out of the water filter as well.
Click to expand...

I don't remember anyone saying they blew all the A/F out of the line. Any A/F left in the lines will not freeze though.
Water will cling to the inside of the lines as the air passes. Then settle back to low spots. May not be much, but it's still there.
 
You can miss sections of water lines using anti-freeze too, but I think the anti-freeze method is a little more forgiving than the air-blow method. For the typical RV owner, anyway. The anti-freeze stays in the system and tends to find its way everywhere over time, whereas air is "one & done", so no second chance if you don't get it right the first time.

One of the pitfalls using air is that people tend to rely on high pressure when the critical parameter is high air volume, either because they misunderstand pressure vs volume or lack equipment that can do it. The average inexpensive home compressor can't do a decent job of it.

The reason people like the air method is not cost savings. It's no residual taste and no need to flush in the spring.
 
I use a $99.00 Goodyear compressor from WalMart which I strapped into a bay to maintain TP, the air bags, grandkids bikes, and blow the lines out for winterizing. It works just fine.
 
I do the same thing. But I'm not in Frostbite Falls Mn. It only rarely gets below 32F here.

Your winters may demand a more stringent winterizing and the recommended 2 gallons of antifreeze. It's cheaper than replacing water lines.
 
I don’t bother blowing lines out. Just run the antifreeze thru. Catch the initial water that comes out in a container; then when it turns pink allow it to go down drain. Once complete turnoff water pump and relieve pressure so antifreeze has extra room if extreme temps make it slushy.
And then use what’s left to pour in drains and toilets.
No problems to date.

I have never winterized black tank flush. Guess I could using outside shower in wet bay of my Montana. But would need external pump for my desert fox.
 
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