Another Water Heater Question

[Wagner4745]

We recently replaced our RV water heater. It is a Suburban SW12DE and it was leaking from around the Anode plug area. Once I got the water heater out I removed the cold water brass fitting and the hot water brass fitting. The hot water fitting had a pressure or back flow spring loaded piece and some of my observance help was telling me that I should remove that and dispose of that device because it isn't needed. Had not replaced an RV water heater before so I'm not familiar with how necessary that type of fitting is to the overall operation of the water heater?

I posted here looking for a more knowledgeable reply and information.

[chirakawa]

The cold water inlet should have a check valve which prevents water/pressure from backing out of the water heater into the cold water lines. Each time the water heats, water expands in the water heater. It's best not to have that backup of pressure, although just momentary, when you flush the toilet or perform other cold water functions. However, mine hasn't worked for the past few years and I just ignore it.

 

I have no idea why you would have the same check valve on the hot water line leaving the water heater.

[Kirk W]

That is a check valve and it isn't critical to the operation of the water heater, but it has an important function and I would keep one on mine. It used to be very common for the check valve to be on the cold water inlet, but more recently it has become more commonly on the hot water out instead for several reasons. Since the water inside of the water heater can't go anywhere unless either income water pushes it out, or air is allowed to enter so that it can drain, the prevention of water loss from a heated water heater via a broken water line can be done by a check valve on either side. By putting the check valve on the outlet side it will prevent the back-flow of water into the tank when you turn off your shower at the shower head and so help to avoid that sudden shot of cold water when you turn it back on. It also means that your water heater bypass don't need a valve on the outlet side as no water can enter from that side so you only need to stop cold water in and open the cross over line, which is often done with 1, three way valve. Not check valve on hot means another valve in the bypass kit. Last of all, many of us run an accumulator tank on the output of the fresh water pump to smooth the surges of using the pump and if there is no check valve on the cold side that accumulator also prevents over pressure in the water heater if the air bubble in the top should be absorbed or otherwise lost.

 

I use a check valve and always in the hot water out.

[Wagner4745]

Thanks chirakawa and Kirk for your reply.

I did leave the check valve in until I got some helpful insight from the members here. While we are discussing this issue can anyone offer a reason for the low hot water pressure at the outlet? This was occurring before water heater change.

[Kirk W]

It just depends upon how much lower the pressure is from the hot water. Keep in mind that the cold water goes directly from the pump or city connection while the hot water is only pushed out of the water heater by the cold pushing into it. For that reason a noticeable decrease in flow is quite normal. Just how much is difficult to judge, but it will be noticeable. In our RV, the difference is also greater in the bathroom sink than it is on the kitchen sink and while the kitchen is a bit closer to the water heater, I think that part of that is also in the cheap bathroom faucet that we have as well. I have studied it for more reason, even flushed the hot water faucet in the bathroom with the faucet cartridge removed in case of some obstruction. Really don't seen much change but the faucet is a cheapie and will be going down the road once I get back from my next travels.