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Country Coach Atwood Water Heater Replacement
My two cubes are toast and in the process of installing new ones. I remember in the old forum seeing nice pics of a few of you replacing them. Can’t remember who. Couple questions:
1. If I close both gate valves in the engine compartment, that preserves coolant for running the engine – correct?
2. How much coolant will I have to catch when I disconnect the heater loops on the back? Is there a low point drain for the hydronic loop?
3. On my 92 CC, I have 2 expansion tanks. A tiny one behind the cubes and a 5gal one behind the shore-power winder. Why 2 and what are the requirements/proper design for expansion/pressure tanks (same thing?)?
4. On both cold-in and hot-out lines, there are these homemade looking steel pipes. Guesses on what they are and function (see picture).
— BTW, my heaters are connected with PEX while the coach itself is PB – so clearly these are not the original heaters.
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7 Replies
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Liam, just pinch off the rubber hoses right at the connection to the water heater before you remove the clamps. They sell tools to do this, they are not that expensive. Get the metal ones.
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Thanks Mike! Any insights on the other questions?
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My guess is that the larger tank is an accumulator tank for your on board fresh water. This provides storage to reduce pump cycles and cushions the hammer from the pump starting and stopping.
The smaller one is probably for thermal expansion for the water heaters. Most systems do not require a thermal expansion tank because the pressure can expand into the fixture supply lines. If a check valve is installed in the water heaters cold water feed line, the pressure will not be able to expand back into the cold water lines resulting in the saftey valve opening. This is usually why a thermal expansion tank is needed. Jeff
Jeff and Lindsay
91 Marathon XL -
Edit: I mis-poke on the path of thermal expansion. I see no way to
Jeff and Lindsay
91 Marathon XL -
Why is it so difficult to edit a post?
Jeff and Lindsay
91 Marathon XL -
My guess is that the larger tank is an accumulator tank for your on board fresh water. This provides storage to reduce pump cycles and cushions the hammer from the pump starting and stopping.
The smaller one is probably for thermal expansion for the water heaters. Most systems do not require a thermal expansion tank because the pressure can expand into the cold water supply and accumulator. If a check valve is installed in the water heaters cold water feed line, the pressure will not be able to expand back into the cold water supply line and accumulator tank resulting in the saftey valve opening. This is usually why a thermal expansion tank is needed. Jeff
Jeff and Lindsay
91 Marathon XL -
Thanks, that makes sense. I think my current setup has check valves on both sides. I did read that is bad if the pressure valve fails so a 2nd tank is installed.
Plan to just install one on the hot side and one 5gal pressure tank on the cold side.
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