water heater Q - Montana Owners Club

Trailer Trash 2 · 05-05-2010, 07:07 PM

can anybody tell me what this pipe is for on the water heater and is it necessary to hav it there. It seems to me that whenI use the shower the cold water can go up into the hot water line making the shower water cold when it is shut off for a few minits.see picture below you can see the cold water line going into the hot line output.

http://i89.photobucket.com/albums/k2...aterheater.jpg

Tag on the above link to see Water heater line.

camper4 · 05-06-2010, 01:20 AM

I believe that is your hot water tank bypas. Used when you winterize the water system so you can drain the water tank and fill only the water lines with antifreeze.
I think there is a valve 'T' at the 'cold' side of that line that selects the direction of water flow, either into the tank or through the bypas pipe. If you have it sending water to the tank inlet, no water will flow through the bypas pipe.

ChuckD · 05-06-2010, 06:48 AM

I believe that pipe allows the antifreeze to flow from one pipe to the other pipe when winterizing and having the how water by-pass on. This way antifreeze does't flow into the hot water heater. IMHO

Art-n-Marge · 05-06-2010, 07:24 AM

On your picture, the bottom T connection for the cold water looks like it has a diverter valve. By turning this diverter valve it allows the WH to be bypassed during winterizing after the WH has been drained.

Don, unless you plan to go winter RVing, you and I don't ever have to worry about this since it doesn't get cold enough where we live.

stiles watson · 05-06-2010, 07:47 AM

In looking at your picture, the line coming in to the inlet marked "cold" is your cold water supply to your WH. As noted by others, at the bottom "T" where the cold water line goes up and connects to the hot water outlet, is a diverter valve. It is closed when the water is not bypassing the WH. It is not mixing with the hot water coming out of the WH. The only time it would is when the valve is turned to allow the cold water bypass the WH. You mixing is happening somewhere else, probably is the shower head itself.

Trailer Trash 2 · 05-06-2010, 02:28 PM

Thanks to all the replys, I was going to get rid of it I'm glad I asked.

sgtpp214 · 05-06-2010, 05:01 PM

Don you have gotten the answer to the picture and what the tube is for, but I have the same question you have about the water in the shower being cold when you turn in back on. Let's see if we have the same situation. When taking a shower I turn of the shower head as I soap up. The old military shower. Then when I turn on the shower head for a few seconds the water is cold before it is hot again. Wonder why this happens?

Trailer Trash 2 · 05-06-2010, 07:12 PM

Quote:

quote:Originally posted by sgtpp214

Don you have gotten the answer to the picture and what the tube is for, but I have the same question you have about the water in the shower being cold when you turn in back on. Let's see if we have the same situation. When taking a shower I turn of the shower head as I soap up. The old military shower. Then when I turn on the shower head for a few seconds the water is cold before it is hot again. Wonder why this happens?

Dave I think we all have that problem, some of us leave a little trickel, and others turn the shower head to the wall and wait for the hot water.
This topic was brought up by me and many other in the past with no REAL answers to the problem.
I realy dont understand why a real plumber cant give a logical answer either. if the hot water is seperate from the cold and has a backflow device on the heater why......does it get cold almost instantly.

camper4 · 05-07-2010, 12:53 AM

Great question! I can't figure it out either.
For me it seems to be in the shower head/hose/faucet area because the cold water is there so fast. For some reason cold water flows into the shower hose and hot water does not. Cold water displaces the warm water in the hose as water continues to slowly run when you turn the head off.
Why is it that only cold water gets there?

Bill-N-Donna · 05-07-2010, 01:34 AM

I may be wrong but here is my opinion on this. The warmth required to maintain a comfortable temperature is quickly lost when the water stops flowing. The distance between the hot water spigot and the nozzle allows the line to quickly start cooling to room temperature. This is what I think is going on.

camper4 · 05-07-2010, 03:18 AM

Okay. A new idea.
The hot water tank has a check valve on the hot water outlet to prevent cold water or antifreeze from entering the tank. When we turn off the shower head, that applies back pressure to that check valve, preventing hot water flow. The cold water has no check valve so it keeps flowing.
That trickle of water that continues to flow when we turn off the shower head is back filled with only cold water.

Exnavydiver · 05-07-2010, 04:34 AM

I have a small question regarding that supposed "bypass" valve in the photo. There is a water heater bypass in the service bay. What sense does it make to have a valve in the service bay AND that hard-to-get-to tiny valve on the back side of the water heater? Just curious... Dave

SlickWillie · 05-07-2010, 06:28 AM

Quote:

quote:Originally posted by camper4

Okay. A new idea.
The hot water tank has a check valve on the hot water outlet to prevent cold water or antifreeze from entering the tank. When we turn off the shower head, that applies back pressure to that check valve, preventing hot water flow. The cold water has no check valve so it keeps flowing.
That trickle of water that continues to flow when we turn off the shower head is back filled with only cold water.

Process of elimination; I think you are correct. I did away with the check valve, and I get a burst of very hot water from the shower head when I first turn it back on. This is just the opposite of how it was before I removed and didn't replace the faulty check valve.

Johnnyg · 05-07-2010, 06:53 AM

I would guess the combination of the hot water cooling in the supply line while static and possible slightly lower flow rate from the hot water side.

farmboy · 05-07-2010, 12:58 PM

Quote:

quote:Originally posted by Exnavydiver

I have a small question regarding that supposed "bypass" valve in the photo. There is a water heater bypass in the service bay. What sense does it make to have a valve in the service bay AND that hard-to-get-to tiny valve on the back side of the water heater? Just curious... Dave

Dave, not all models have the service center in thier rigs. My 2005 29955 has all hookups on the outside of the rig in various spots, thus only one by-pass valve, which is as pictured by op.

You may also like: