Winterizing, Air Pump, PSI, mystery?

[Atsushi]

I've attempted to use my Viair compressor for the first time to blow lines (I usually use just AF).


I normally use this compressor to put air in the trailer tire (65 PSI).


My fear was to put too much PSI in the system and cause damage, so I recruited my wife to have her closely monitor the pressure.


To my surprise, the pressure never went higher than 20 PSI.


I thought of existence of leak somewhere, but when I later put AF in the system, there was no sign of leak anywhere.


Here is my only theory:


When I put air in the system, I didn't bypass the WH. Did WH somehow release pressure?


If there is a leak somewhere, my common sense tells me that the pressure shouldn't even get to 20 PSI, so I the system must have been able to hold the pressure up to 20 PSI but not beyond.


What can explain this?


Atsushi
2016 FC23D

[Adventure.AS]

Were any faucets open (including the outside shower?)

[Atsushi]

Thanks for your response. That's the first thing I checked, and all of them were closed.

[azflycaster]

At what location did you attach the air hose to the water system?

[ROBERT CROSS]

Originally Posted by Atsushi

Thanks for your response. That's the first thing I checked, and all of them were closed.

Did you add air thru here?


Even with your smaller compressor I would not let the pressure build up too far unless you attach a regulator on it to stay below, (I use 35psi constant), 60psi. Get a volunteer and have them open one outlet at a time while you operate the compressor.

I have a 26gal compressor and use a steady 35psi as I open one at a time.

Bob
🇺🇸

[Atsushi]

I put an adapter with schrader valve to the city water connect. Then put air like I do to tires.
Thank you.

[ROBERT CROSS]

Originally Posted by Atsushi

I put an adapter with schrader valve to the city water connect. Then put air like I do to tires.
Thank you.

Get rid of the schrader valve. Leave compressor attached.

Bob

[Atsushi]

I was afraid of exerting too much pressure, so I instructed my wife to stand right next to the pressure gauge and radio me if pressure approaches 40 PSI. But the pressure never even gone beyond 20 PSI.


I wasn't sure if 20 PSI was sufficient, but I repeated opening and closing of all faucets a number of times until water stopped splashing out of them.


My plan was to stop there, but since I wasn't sure 20 PSI was sufficient, just to be sure, I put AF too (And there was no sign of leak).

[Atsushi]

Originally Posted by ROBERT CROSS

Get rid of the schrader valve.

Bob

Oh!? My pump is primarily for putting air in the tires, so schrader valve adapter was to accommodate my pump.


That's where the leak was?


Maybe I didn't screw the adapter tight enough?

[uncle_bob]

Hi

A small DC powered compressor will not move very many CFM of air. For blowing up a tire this just means waiting for a while to get the job done.

For blowing out lines, CFM very much *does* matter. A large(r) AC powered compressor is a really good idea. Having a regulator on the compressor and a filter in the air line are also worth doing.

The plumbing (faucets / pipes / valves / water heater) in your trailer are all good to at least 60 PSI. Normal shore water will get to this point or higher. The fittings are all pretty much what gets used in a normal home. They can take a lot of pressure.

If your compressor never gets above 20 PSI either it's defective or there is a leak. One scary defect would be a broken pressure indicator. Much more likely is a valve or faucet somewhere that simply isn't closed all the way. With a small compressor, a very small leak will be an issue. The same low CFM will make properly blowing the lines nearly impossible.

One other thing to watch on any compressor is the duty cycle rating. Generally they have some sort of "run for a maximum of XX minutes" or "50% duty cycle" or other yack about not running constantly. Yes, a big shop compressor may be perfectly happy running constantly. Something targeted at tire inflation usually will have some fine print.

Cost wise, you can get a pretty big compressor at the local big box store for < $100. If you go up to around $200 you can get something that will barely run on a normal 15A 120V socket ....

Lots of fun !!!

Bob

[Adventure.AS]

I use the Viair 450 automatic. After draining the system using the low point drains and then closing them I begin with the air pump. Because it doesn’t have a pressure tank I pressurized the system to 45 PSI using the Schraeder adapter with all faucets closed then opened the farthest one on cold and then closed it, etc., etc. The system needed to be replaced-pressurized after each opened/closed faucet. It doesn’t have the capacity to maintain more than 20 PSI if a faucet is open.

I think you must be using a different procedure as you can even use a bicycle pump for the job.

BTW did you open faucets one at a time when you pumped in the antifreeze?

[Atsushi]

Originally Posted by Adventure.AS

I use the Viair 450 automatic. After draining the system using the low point drains and then closing them I begin with the air pump. Because it doesn’t have a pressure tank I pressurized the system to 45 PSI using the Schraeder adapter with all faucets closed then opened the farthest one on cold and then closed it. The system needed to be replaced-pressurized after each opened/closed faucet. It doesn’t have the capacity to maintain more than 20 PSI if a faucet is open.

I think you must be using a different procedure as you can even use a bicycle pump for the job.

BTW did you open faucets one at a time when you pumped in the antifreeze?

Yes, I opened faucets one at a time when I pumped AF.
In the end, I think I should just stick with what I'm comfortable, which is AF.

[Adventure.AS]

Originally Posted by Atsushi

Yes, I opened faucets one at a time when I pumped AF.
In the end, I think I should just stick with what I'm comfortable, which is AF.

Did you use a winterization kit at the water pump? You can also drain the antifreeze from the system now to save a step in the spring as leaving it in the pipes serves no purpose.

[Atsushi]

Originally Posted by Adventure.AS

Did you use a winterization kit at the water pump? You can also drain the antifreeze from the system now to save a step in the spring as leaving it in the pipes serves no purpose.

I normally unscrew the WP inlet and screw on a hose to suck AF out of jar.
But this time, I used a hand pump and pumped AF into the system from city water inlet. WP is in such a tight space, and I didn't want to deal with it this time. AF came out from all facets and toilet, so I'm sure lines are protected (even though compressed air might have not).

[uncle_bob]

Originally Posted by Atsushi

I normally unscrew the WP inlet and screw on a hose to suck AF out of jar.
But this time, I used a hand pump and pumped AF into the system from city water inlet. WP is in such a tight space, and I didn't want to deal with it this time. AF came out from all facets and toilet, so I'm sure lines are protected (even though compressed air might have not).

Hi

Simply running AF through the city water inlet does not protect the water pump. There is no way for it to get to the pump because of the way the pipes run.

Bob

[OTRA15]

^^^^^ x2

[Atsushi]

Ah! I didn't think about the WP.
Actually, we are going to use the trailer in a couple of weeks before winterizing last time for the winter (until then, the temperature forecast appears warm enough). So I'll go back to my original method of using onboard WP.

[CruizinDux]

Originally Posted by ROBERT CROSS

Get rid of the schrader valve. Leave compressor attached.

Bob

I use the schrader valve without the stem so no flow reduction when I'm using the 110VDC inflator and the 12VDC inflator. If I'm using the rigid compressor, I use a quick disconnect connection. In all instances final consection is vial a hose thread fitting. The schrader sticks out horizontally and the quick disconnect via a camco ell so it hangs down to easily accommodate the shutoff value, pressure gauge etc.