1st Time Owner - 2005 Coachmen - Hot Water bypass question

[ImSpartacus]

Hello,

I am preparing to winterize, have a question about bypassing the hot water heater before putting antifreeze into the plumbing.

All generic info online suggests there are three valve and two valve bypass systems for the hot water heater. However, in my system there is only a single valve. There is a bypass tube affected by the valve, but, it seems impossible for this to truly bypass the hot water heater unless the hot water outlet is in itself a one-way valve allowing hot water to flow out one-way only.

Can anyone confirm this is how the bypass system is designed, one valve to manually operate and the hot water line exiting the top of the water heater is one-directional only?

Also, anyone familiar with this particular model who knows exactly where the water pump is, I'd love to know.

Thanks,

 

[Henry J Fate]

Yes, a back check valve is commonly used at the tank outlet. This prevents water from back flowing into the tank. A valve at the inlet will bypass the inlet.

If possible, it is good to verify that the check valve is not passing water. Some will leak over time. A little leakage is fine and will not affect the antifreeze process much. Keep the water heater drain plug out so that if any water does get in while winterizing, it will flow out.

 

[Rene T]

The valve Henry is talking about is a directional valve. In one position, water is directed to the heater. In the other position the water or antifreeze goes up that short pipe. If then tries to go into the tank but it is stopped by the check valve he mentions.

 

[Kirk]

Can anyone confirm this is how the bypass system is designed, one valve to manually operate and the hot water line exiting the top of the water heater is one-directional only?

The actual location of the valve could be anywhere but it is a valve with one water entry and the exit goes either to the water heater or to the bypass. Notice there is a check valve into the cold supply and on the outlet of the hot as well.

exactly where the water pump is, I'd love to know.

The most common place to have the potable water tank is under the bed and in most cases the pump is next to the tank and there is usually also a drain valve for the tank located there.

 

[Henry J Fate]

There are several ways of plumbing this. In the OP era of 2005, it was common for a manual bypass valve at the inlet and a back check valve on the outlet side of the tank. No inlet back check.

In theory it is a little awkward but when you add in the ability to winterize, it becomes more economical. Ideally you want a back check at the inlet to prevent hot water from back flowing into the cold water lines. This occurs mostly from thermal expansion of the water when it is heated but there are a few variables that come into play. My current system has no inlet back check. There is one at the outlet. I do on occasion notice the thermal expansion at cold water taps but it has never pushed deep enough out the inlet to contaminate the cold water supply.

I did consider installing a back check at the inlet but decided to let it expand as it is so that the pressure in the system remains lower. An inlet back check would put all of the thermal expansion pressure into the hot water side of the plumbing. The only defense against that build up would be the safety pressure release on the outside of the hot water tank. No idea if it would ever get high enough and open the safety but it never did with the single back check and it has never contaminated the cold supply so I just left it as is and it is fine.