Water heater check valve

Captain Bud · 03-22-2006, 11:14 AM

I just completed a 3 month trip to Fla. and except for one small glitch it was perfect. One of the check valves failed on my hot water heater, (the same one that failed last year.) I found out that the valve was only needed if you winterized by bypassing the hot water heater and filled your water system with anti freeze. I blow my system down with compressed air so this valve is not necessary. I just removed the cheap valve seat and spring and reinstalled the valve casing, and I have no more problems.

Captain Bud · 03-22-2006, 11:14 AM

I just completed a 3 month trip to Fla. and except for one small glitch it was perfect. One of the check valves failed on my hot water heater, (the same one that failed last year.) I found out that the valve was only needed if you winterized by bypassing the hot water heater and filled your water system with anti freeze. I blow my system down with compressed air so this valve is not necessary. I just removed the cheap valve seat and spring and reinstalled the valve casing, and I have no more problems.

troth · 03-23-2006, 02:38 AM

Captain Bud, I'm envious. At least you could access the backside of your water heater. I've gotta pull the complete heater out to access mine on the 34D. Another when I get a round tuit.
I plan on installing 1/4 turn ball valves on both the in & out lines so I can positively isolate the WH manually.

Pete B · 03-23-2006, 04:04 AM

I had the check valve on my 03 Brave fail this year. The tech who repaired it was able to get behind the water heater without removing it. But the access is small and you have to be a contortionist to get to it. Better him than me!

MrTransistor · 03-25-2006, 07:36 PM

Hi All,
I just posted two pictures of an all metal replacement check valve. Made in the USA, it seems to be of a much higher quality than the cheap made in Mexico check valve that gets installed by motor home manufacturers.

I also discovered that with both valves installed or just the bottom cold water inlet, you can't drain the water heater with the drain valve that's below the water heater. I had installed a replacement valve in the cold water inlet to get by while I researched a better valve. To my surprise, when I went to replace the cheap valve, I couldn't drain the heater. Thought about it after I got quite wet trying to empty the tank and moved the new valve to the top hot water outlet. Now the heater is easy to drain, just open the ball valve and release the poppet in the pressure relief valve at the top front of the tank.

It also occurs to me that with no check valves at all, the hot water may circulate through the piping external to the tank. This would be piping with no insulation and would cause the heater to run more than it would normally. I understand that check valves aren't used in household plumbing, but there, only one cold water line goes to the heater and one hot line leaves it hence, no circulation. In Winnebago designs, there are two lines to and two lines from the heater. Not sure why but this seems to be the reason for the check valves. Though I think one would be sufficient.

Captain Bud · 03-26-2006, 02:05 AM

Mr Transistor, you're pics are great However I think you are mistaken with the valving setup. The reason for two ckeck valves (in and out) is to be able to isolate the Water Heater during the winterizing process. If one doesn't use this method and decides to blow down the system with compressed air the only check valve needed is the one on the cold side. All I did was eliminate the check valve on the hot side (outflow) and my system works fine. AlsoI only have two lines feeding my heater one in and one out....

MrTransistor · 03-26-2006, 07:17 AM

Hi Captain Bud,
Correct, one cold, one hot - in and out of the heater. But if you check the plumbing diagrams, there are four lines running to the hot water heater area. Don't know why but I'm intending to look at it closer. I assumed it had to do with ˜bypass'.

We are full timers (5 years) and have yet to winterize. When you ˜blow down' your system, is it your intention to empty the water heater of water? If so, short of removing the drain plug on the outside bottom of the heater, there would be no way to empty the tank ˜backwards' through the cold water check valve at the bottom rear. Having never winterized, is the procedure to run antifreeze through the entire system including the water heater? Or if purging with air, to remove ˜all' water?

Incidentally, so far, the new valve seems to be working fine.

"007" · 03-26-2006, 07:25 AM

With all the problems with check valves just to prevent RV-anti from entering WH, a by-pass kit is the easier fix, thats all I ever had very simple and less costly.

"007"

MrTransistor · 03-26-2006, 09:14 AM

Hi All,
Well, I just reviewed the plumbing diagrams for the 04-s40wd and I'm a bit surprised that it's plumbed the way it is. Seems like a lot of pipe for what is required. First, the four lines are - two (one hot one cold) from the water compartment to the water heater area and two (one hot one cold) from the water heater area to the bathroom sink and shower.

As for the check valve, I can see no reason for its existence in the cold line. When in normal operation, one check valve would be sufficient and when in bypass, the bypass valve closes the line to the cold water inlet making a check valve redundant. If no valves at all are installed, a slight amount of hot water may gravity drift out the top of the tank into the lines but this would be minimal and no reason for the valve.

As 007 says, check valves to prevent RV- antifreeze from entering the water heater in bypass would make sense to me if the Aluminum water heater would be damaged by the antifreeze. Does anyone know if this is the case? If you can't allow antifreeze into the water heater, and it won't drain in either position of the bypass valve, how do you prevent freeze damage to the tank? I have never read the book on winterizing. Does it say to empty the water heater by removing the drain plug at the bottom outside of the tank?

Is anyone from Winnebago reading this? If so, please feel free to comment on the design reasoning.

tomsm · 03-26-2006, 10:17 AM

Hi Mark,

The only reason for the WH bypass is to save the price of 6-10 gallons of anti-freeze (about $3.50/gal). Yes, you do drain the WH. Our payback for dodging hurricanes all summer here in FL is not having to winterize!

You drain the WH by taking out the plug at the base and opening the Hi-temp popoff valve at the top for vacuum relief. Don't winterize now, but did in Colorado...

MrTransistor · 03-26-2006, 10:52 AM

Hi Tom,
Well, that explains it. For now, I'll stick with one check valve in the hot water out at the top. Thanks.

Captain Bud · 03-27-2006, 01:42 AM

Tomsm replied correctly, that you remove the drain plug and release the safety valve. I personally feel that you are also draining any debris that might have collected in the Water Heater.