Winterizing Issue

[Lost]

I am winterizing my rig today... followed all the instructions, drained all the water, hot water heater etc. I hooked up the air to blow the lines out at 30 psi. All the lines emptied out as the air went through them except the kitchen sink... no air is going through it I closed all the faucets and even the water heater, I left open the kitchen faucet and still no air. I could see no water coming out if it all drained but there should still be air coming out. Any idea of why?

[Lost]

Figured it out.. to get full pressure in the lines the low point drains need to be closed.

[Ron]

Your going to get a Headache if you keep doing that...lol

[erjs05]

I did the same thing today and it took me a while to figure it out. If you watch the Keystone video they don't cap the lines until the last step. Being my 1st time doing this I was worried I didn't get all the water out so I repeated it 3 times and only air came out the last 2 times. The video also shows dumping Rv anti freeze down the drains. Is that to push water out of the trap, because I was thinking won't it just go into the grey water tanks?

[JRTJH]

Yes, when you pour antifreeze down the drains, it pushes the water out of the traps and protects the P traps from freezing. The water that is in the gray tanks should run out the open drain valves.

Honestly, there is very little water in the gray tanks if they were dumped properly, so the little that comes from the P traps mixed with the antifreeze should be OK.

The problem with water in the tank is not actually with the tank, but in the drain line leading from the tank to the dump valve. Any water left in the tank would simply lay on the bottom and when it freezes, it has nothing to expand against and won't cause damage. Water left in the drain line, if it fills the line completley and lays against the dump valve or in a bend, could freeze, expand and crack the pipe. That's why I recommend leaving the drain valves open during the winter. If your'e concerned with rodents (mice or bigger) getting into the tank, then put a piece of aluminum window screen over the end of the sewer connection. It will drain but nothing can get into the tanks.

[Dhuhn]

I also winterized my rig today so depressing can't wait till spring so we can go camping again