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glassbird 10-21-2018 10:40 PM

help a newbie with heater bypass? (with pics)
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OK, my first question on this forum although I have been lurking for a few months...

I bought a 1988 Thor Citation 20 foot trailer about 3 months ago. The previous owners neglected it badly, and I am gradually repairing and replacing things. I am currently at the point where I am going to replace the water pump (the original leaks like a sieve), add a "pump converter winterizing kit", and install a heater bypass set-up to avoid filling the heater with anti-freeze. Once that is done, I will be winterizing it and continuing repairs in the Spring.

I am ready to do the first two projects, and am a pretty confident DIY-er...but the heater bypass has me stumped. I understand the the antifreeze past the heater...but I look at my pipe arrangement and simply can't seem to wrap my head around what part goes where. Nothing seems to match up with all the diagrams and YouTube videos I have looked at.

Before I start cutting it really all that horrible to just fill the heater with anti-freeze? Yes, I know it will cost more money, but I would prefer that to rolling around on that cold floor with my arms jammed in the cabinet. Its not an easy location, and worse coming at it from the outside.

Below (hopefully) are pictures of the pipes. One pic is labeled, and the other is the same area from a different angle which might help more experienced eyes confirm what I think I am seeing. Can someone tell me where I should cut, and what part of a bypass kit goes where, in this lay out?

Please excuse the cobwebs...haven't cleaned this area yet. I hope these pictures come thru...

Thank you!

mountainsam 10-21-2018 11:17 PM

have you thought about just blowing the lines out rather than using antifreeze?

glassbird 10-21-2018 11:23 PM

Yes, but I don't have an air compressor. Might be able to borrow one....hmmm...

JamieGeek 10-22-2018 12:51 AM

Can you get access to right behind the heater? (In the pics it looks like the heater is the big brown thing in the back?)

The bypass kit would go right on the back of the heater between the intake and output lines. You're just getting confused because of where all the lines are going--just look at the two pipes on the back of the heater: cold in, and hot out. The bypass kit goes right there.

glassbird 10-22-2018 02:58 AM

I see what you are saying...and that does make more sense. No, getting to the back of the heater is even harder than getting to those pipes at the front of the pictures. I don't think my arms are long enough! The air compressor method is looking more viable, at this point.

I must know someone with a compressor. Or maybe I can buy something small enough to do the job, and yet not take up too much space.

Time to look at more YouTube videos!

Dilley-Dilley 10-22-2018 03:27 AM

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Attachment 13592

Dilley-Dilley 10-22-2018 03:31 AM

Hopefully this helps. The exact placement of the valves, piping and fittings is up to you but this is what you are trying to achieve. During normal operation the valve on the bypass line is closed and the cold and hot water valves are open. In bypass mode the hot and cold valves should be closed and the bypass valve open.

Dilley-Dilley 10-22-2018 03:37 AM

I would probably install the hot an cold water valves as close to the “T” fittings as possible. That would reduce the amount of coolant that enters those two lines. Good luck and happy camping.

glassbird 10-22-2018 03:50 AM

A HA! Now I get it! And I can reach those closer pipes, with some struggle, but not impossible. OK!

Wow, and thank you to everyone. Now I can get this done!

Coveman2 10-22-2018 12:34 PM

Winterizing Supply Pipes
I use a bicycle pump and it works great, just open one tap at a time and have someone turn the taps off and on and after you have purged all of the lines you can add antifreeze through the pump or get an antifreeze pump

Long & Winding road 10-22-2018 02:51 PM

That was an awesome diagram Dilleyx2! Very helpful.

Glassbird - take some pictures when your done. Let us know if you need anymore help. This site has lots of knowledgeable people on it.

Dilley-Dilley 10-22-2018 04:07 PM

Glad to be helpful [emoji846][emoji1303]

DenverTransplant 10-22-2018 04:16 PM

You can also get a kit from Camco that uses one three way valve on the cold water inlet and a check valve on the hot water outlet. Haven't ever used one of these but the reviews are generally good.

jimbo12 10-22-2018 05:11 PM

Looks like you have Polybutylene (PB) pipe which is no longer used due to high rates of failure. If you can get to all of the piping easily then you might want to think about going PEX and replace everything. Otherwise, you need to be careful that you get PB to PEX transitions when installing the valves and bypass pipe. PB is not the same diameter as PEX and will require special transitions.

Dilley-Dilley 10-22-2018 05:21 PM

The Camco bypass looks like a cool piece of equipment. [emoji1303] I think the problem with it in this application is that Glassbird has a challenge in accessing the water lines entering and leaving the water heater. The Camco bypass looks like it has to be installed right at the water heater. It looks like Glassbird needs more of a remote inline application. Our 2017 Miramar 34.1 has a water heater bypass similar to the design that I diagramed

Dilley-Dilley 10-22-2018 07:48 PM

Glassbird, Are you sure that there is no access panel in the floor above that water heater where the connections are? It seems like there has to be some way to get at those threaded fittings. What is above where the water heater is? If you had to replace the water heater, how would that be done? I think that as jimbo12 suggested, you might want to consider a repipe with PEX in the future. If it is possible to get those hoses disconnected from the water heater then you might want to assemble new plumbing in that compartment using PEX. You could preassemble it how you want with all the fittings and bypass in your garage and then install it as a unit. If you could access the piping in other areas outside of that cramped compartment then you could cut and splice the plumbing in those areas. I know this is a little off the original question but if you’re going to modify and improve that plumbing you might want to just change it out while you’re at it.

bevedfelker 10-22-2018 09:51 PM

1 Attachment(s)
Glassbird -- you got lots of good suggestions; however, no one showed you a diagram of what you are conceptually trying to do, & what exactly are you bypassing. Here is a conceptual drawing that shows you what you are trying to accomplish.

The whole concept is to By-pass the water heater so that when you winterize you aren't pumping 6 gallons of RV antifreeze into the water heater tank. So you have a cold water line going into one end of the water heater tank and you have a hot water line coming out of the water heater tank. So to complete a by-pass installation you need to install a valve in the cold water line going into the tank to close off that potential flow. Then you need to install a valve in the hot water line to close off that potential. When those two valves are open your water heating system is operating normally. When you close both those valves your water heater tank is now isolated -- no potential flow into it, no potential flow out.

Now comes the By pass piece. Close to those two valves on the intake and output of the water heater you are going to have to install a line that connects the cold water input to the hot water output. In the middle of that by-pass line you need another valve.

So with the cold water input and hot water output valves closed, you would open the valve in the bypass line you just installed. You can see that any cold water flow going to the water heater is stopped and that cold water flows directly into the hot water output. When you are winterizing, the antifreeze you syphon into the cold water line now bypasses the hot water tank and only flows into and through pex tubing. None gets into the hot water heater.

Part of winterizing is to take the plug out of the hot water heater tank so that the 6 gallons of water drains out.

So --
Normal Operation -- Cold Water Input Valve to heater OPEN Hot Water Output Valve OPEN Water Heater Bypass valve CLOSED

Winterizing Operation -- Cold Water Input Valve CLOSED Hot Water Output Valve CLOSED Water Heater Bypass Valve OPEN

You can see this clearly in the two schematics I attached.

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