The Water Heater Bypass System On My RV Has Problems

by Randall Holst
(Anderson, S C)

I have 1-3 way valve by the water heater and the second 3 way valve in the plumbing and discharge compartment. The unit is a 2002 Fleetwood Expedition 34M I just bought and am trying to get the pressure system working. With the bypass valves set to bypass the heater, the pump pressurizes the system and shuts off but not with either 3 way valve set to include the water heater. How is this system plumbed?

ANSWER: Greetings Randall thanks for submitting your question on our Ask An RV Question Page.

I am afraid I cannot tell you how your RV Water Heater Bypass System is plumbed, but based on your statement, I can pretty much tell you that there are two common causes to the problem you are experiencing.

1. Your RV Water Heater could have been drained for winterization and you have not allowed the water pump to run long enough to fill it back up.

2. The other possible problem is that you have a leak in the inlet or outlet pipes on the back of the water heater which is not allowing the water system to pressurize. When the Water Heater is bypassed these inlet and outlet pipes are also bypassed allowing the pressure to build. The water heater itself could also be leaking.

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If you have determined that your water heater is full then you will know that there is a leak somewhere in the water heater area. The first place to check is the water heater compartment with the water pump running. You are looking for any steady leakage in that area.


Just a note here it is normal for the water heater pressure relief valve to have an occasional drip here and there. A constant flow of water would indicate a problem.

If you do not find any leaks in the water heater compartment then you will have to gain access to the water connections at the back of your water heater from the inside of your RV. Depending on the configuration of your RV this may be a task unto itself just gaining access.

Once you get access you need to check the in and out water connections to the water heater. If it is a large leak there may already be evidence of the leak present. If there is no evidence of a leak you will need to turn on the water pump and look for any apparent leaks.

Hope this helps.

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