Would like the "why" behind one step in blowing out lines in winterization process

[bonginator]

I completed my two phase winterization today on my 2008 23 fb. There is one step that sort of confounded me as to why it was done that way. I am wondering if anyone can explain it.

The manual instructions say that before you blow the lines, you should:
1. disconnect the exhaust outlet for the water pump (I assumed this is the same as the outlet line.). Then it says to
2. disconnect the input line for the water pump
3. Then open all of your faucets both hot and cold
4. Then blow the pressurized air through the system at 60 or greater PSI using the city water inlet.

My questions:

Why do you leave the output line and input line from the water pump disconnected when you blow the pressurized air? Does it just assume that the pipes are directly connected to the city water inlet system so the air doesn't need to flow through the water pump to push it out of the system?

Is there a water filter exhaust outlet AND an output line or are they one and the same?

Thanks everyone!

I continue to learn....

Sandy

[dznf0g]

There is a check valve in the pump. Disconnecting the inlet side allows any water in the "draw" tube to drain back to the tank. Disconnecting the outlet side allows air to purge out of the pump exit tubing.

Your last line....water filter or pump?

[bonginator]

Originally Posted by dznf0g

There is a check valve in the pump. Disconnecting the inlet side allows any water in the "draw" tube to drain back to the tank. Disconnecting the outlet side allows air to purge out of the pump exit tubing.

Your last line....water filter or pump?

Sorry - my last question I meant to say water pump exhaust filter and outlet line! Must have been that G &T after the job (-;

[dznf0g]

Hmmm...exhaust filter...not sure what that is. I have a filter on the inlet side of the pump. I take it off and drain the water out of it and put it back on. Do you have a pic?

[bonginator]

Sorry, it is not a filter. My manual states water pump exhaust. Is this just the output line from the water PUMP?

[Ag&Au]

Originally Posted by bonginator

Sorry, it is not a filter. My manual states water pump exhaust. Is this just the output line from the water PUMP?

Yes, they are talking about the pump output line.

I do it somewhat differently and in my mind more throughly.

After doing the blowout with every thing open, I close all the faucets etc and reconnect the water pump. I pressurize the system again. I start with the highest faucet, and open only it. I leave it open until it is totally dry, no water, mist or fog coming out. I then close it. I do this to each faucet or device working my way lower until I finish up with the low point drains.

Ken

[Gringo]

I just drain all the low points and the heater, pour two gallons of pink anti freeze in the water tank, and run the pump until I get pink stuff out of each faucet. I dump several cups of the antifreeze down the toilet, and figure that's got all the lines, the heater, the traps, the tanks, and the pumps all set. Sterilized, too.

[Protagonist]

Originally Posted by bonginator

Why do you leave the output line and input line from the water pump disconnected when you blow the pressurized air? Does it just assume that the pipes are directly connected to the city water inlet system so the air doesn't need to flow through the water pump to push it out of the system?

Remember, you're hooking up your air line to the municipal water inlet. If you were hooking up a water hose to the municipal water inlet, the water would already be pressurized, and you wouldn't even turn on the pump. Right? The municipal water doesn't go through the pump. So, when you hook up an air line to the municipal water inlet, the air doesn't go through the pump, either. At least that is true if you've got separate inlets for municipal water and for filling the freshwater tank.

By disconnecting the inlet and outlet lines from the pump, you allow air to blow though those lines, without going through the pump.

[Silver Goose]

Originally Posted by bonginator

...
The manual instructions say that before you blow the lines, you should:
1. disconnect the exhaust outlet for the water pump (I assumed this is the same as the outlet line.). Then it says to
2. disconnect the input line for the water pump
3. Then open all of your faucets both hot and cold
4. Then blow the pressurized air through the system at 60 or greater PSI using the city water inlet.

My questions:

Why do you leave the output line and input line from the water pump disconnected when you blow the pressurized air? Does it just assume that the pipes are directly connected to the city water inlet system so the air doesn't need to flow through the water pump to push it out of the system?
...

If you look at the plumbing around the water pump you will discover there is a section of water line between the outlet of the pump and the Tee where the pressurized city water enters the trailer. By applying air pressure to the city inlet and opening faucets and low point drains, the air will purge the lines from the city inlet and through the Tee to the open faucets. The one-way check valve in the water pump will prevent water from escaping that section between the pump and Tee particularly if there is a loop or an uphill slope in the pump's output line.

The procedure in your manual will insure that all the lines will be purged of water. I would add 2 steps: Use a towel to catch any water that comes out of the disconnected line, and while the lines are disconnected, momentarily operate the water pump to purge any water that might remain in the pump.

I think very few of us are that thorough when blowing out the lines. Many of us drain the lines, tanks and water heater, then bypass the water heater and maybe blow out as much water as feasible. Some have also installed a Tee with a selector valve on the input side of the water pump and use the pump to flood all the lines to each faucet with the pink antifreeze. This may be the belt and suspenders approach, but for those who live in particularly cold climates, it can proved added piece of mind.

If your trailer is equipped with an external faucet or shower, don't forget it.

[bonginator]

Thanks. This all makes sense.

One more question - before I disconnected the low point valves and blew the lines through the city water inlet, I ran the pump and got water out of all of the faucets and toilet as much as I could (with my fresh tank empty).

When I then blew the lines with air, I did not see much at all come out of the faucets. Just a few drops.

Is this normal or when you blow the lines do you usually see lots of water come out. It made me wonder if my air pressure was correct - I double checked it an ran the blow out 3 times. Same result.