Just using a compressor do I need to bypass water heater?

[GettinAway]

Originally Posted by dwverhagen

On my 2010 Flying Cloud 25FBT the heater is under the curbside bunk and the by pass valve(s) can be easily accessed from outside storage compartment

I wish AS didn’t change this. I have a low point drain I can get to from the front curb side storage compartment, but my water heater bypass is only accessed through a small hole under the twin mattress.
I turn on the flashlight function on my cell phone and lay it under the mess of wires and plumbing by the water heater, and I can at least see half of that bypass valve.

[GettinAway]

Just a final note. I did end up bypassing the water heater. I was concerned there may be some water in that bypass line. Just couldn’t ignore it. Not sure how water would have ever gotten in there, but decided to be safe rather than sorry. All lines blown out twice. Low point drains three times. Just ran the pump dry with low point drains open. Hoping they pump is protected.

[Silvr_Bullet]

When bypassing valves are in bypassed position, water is forced from the line when a hot water faucet is opened under air pressure. If you want to ensure the hot water heater is empty beyond just draining , use a vinyl small diameter hose inserted through the drain plug and down into the hot water heater, syphon with a quick pull of breath and about a gallon of water will be expelled.

[GettinAway]

Originally Posted by Silvr_Bullet

When bypassing valves are in bypassed position, water is forced from the line when a hot water faucet is opened under air pressure. If you want to ensure the hot water heater is empty beyond just draining , use a vinyl small diameter hose inserted through the drain plug and down into the hot water heater, syphon with a quick pull of breath and about a gallon of water will be expelled.

Yes, good info. We used to get some pretty smelly water from the water heater. Figured out it was chemical build up in the water heater. We filter every drop coming into the trailer, trying to prevent it from happening again. Getting every drop out, and rinsing it out is also part of the plan.
Thx

[Silvr_Bullet]

Every drop of water isn’t going to be removed, but it’s sure better than leaving nearly a gallon of water in the tank that would be left if just draining the tank with gravity alone. Some use compressors with high volume of air to dry it out, I don’t have that type or capacity compressor.

[Ky76Argosy]

Ok, read a lot, learned a little, and got some thoughts to express, and few questions. First, what is max pressure used if only use compressor to blow lines? Second, if open low water drain does that not siphon out water? Lastly, what pressure does WH relief valve hold? Any comments as I wonder. As for my process, I note and remind all, raising opposite side AS from low point drain increases water discharged even out of bottom of WH grain plug. I use compressed air in water line using an air plug in water inlet, pressurized to 25#. At this point WH by-pass lines closed. I pressurize and blow out first the low point drain. Then pressurize and open each faucet kitchen, tub, toilet flusher, sprayer, sink, hot/cold, multiple times, until no or almost no moisture/mist is seen. Then the again blow out low point drains. Start at kitchen faucet ie furthest from low point drains. For WH, after water lines blown out, I open the WH by-pass connection lines and pressurize the WH. I then open the plastic drain plug, which blows out the tank. Yes, I have found yucky sludge like remnants thought to be old sediments, despite filtering, and possibly film like from moldy-algae water. But after few few tries that is gone too. I like idea of pressurizing thru WH tank relief valve, but can do same thing from fresh water inlet. And that blows out WH by-pass lines. But I have only replaced 1/2 the Cooper with PEC pipe, so I worry some low point in waterline pipe may have condensation moisture, or few drips of water in cooper, and possible freeze. I close WH bypass and run 1 gallon of RV Antifreeze, good stuff, thru lined with my water pump bypass installed, easy peasy. The water in drains is saturated with antifreeze when I open each faucet hot/cold until see pink. Bottom of jug poured in tub/sinks. I keep open my 40 gal fresh water tank drain line which siphons out fairly completely. Yes rinse waterlines twice in spring before reuse. All done under an hour, faster if help blowing lines.

[Dennis C]

I set my compressor to 50 PSI when I blow out my lines. I don't close my water heater bypass valves, but I do run open the water heater drain and let the compressed air push out any water remaining in the water heater after draining it. It's surprising how much water comes out!

[GettinAway]

I used to run my compressor at 40, but upped it to 50 this year. I have a giant syringe with tubing, that I use to pull water out of the WH, and add rinse water.

[Mike Spicule]

I thought putting compressed air through the water heater can damage it. No one is worried about the recommendation not to do that? Or am I missing something.

[dznf0g]

Originally Posted by Mike Spicule

I thought putting compressed air through the water heater can damage it. No one is worried about the recommendation not to do that? Or am I missing something.

I use regulated air at 55psi. I blow out everything. Large compressor.

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[paulbiere]

I need to start doing that during winterization/ when I moved my trailer this week water came out of the open water heater drain. I was surprised, thought that the drain plug would be at the low point.

[jcanavera]

I first dump the hot water tank through the tank drain plug. After that is done, I replace the drain plug and pump air through the city water inlet. I first open the cold water outlets in and outside the trailer and then the hot water outlets. Once I finish that I then turn the bypass valves into their bypass mode and then again open each water outlet first cold and then hot. The reason is that if I must make sure air is passing through each pipe in the trailer. Only blowing air through the lines with the bypass valve closed can leave water in the area of the pipes that bypass the water heater. So by blowing air through the tank first, and then activating the bypass and blowing again, you move air through the portions of the lines that will trap water based on the bypass valve positions.

Obviously each model over the years has made piping runs and valve positions for bypass mode unique. In my trailer I did realize early after inspection, that in my Classic, water could remain trapped in some areas of the piping and miss the blow out process depending if the blow out occurred with the bypass valves were closed and when they were open. Some of you may find after looking at your bypass routing than there would be no possibility of water being trapped in a section of pipe. I can only comment on my 2004 Classic Slide Out. It's worth the time and trouble to either track this down, or if you aren't sure, blow the lines out with an empty hot water tank (and the drain plug closed) with the bypass in the closed position, and then again with the bypass in the open position.

Jack