Hot Water tank will not fill

moose53

Active Member
Our neighbor has a new 3800 Cyclone and the hot water heater will not fill, Is the hot water heater bypass located in a strange place? I hate to open up the compartment behind the UDC, this unit hasn't been slept in yet.
 

CactusTwo

Active Member
Oh boy them too. We received our 3950 with the main HW bypass closed. The side panel in the basement will have to be opened, 2 screws thru the left side of UDC and a few thru the basement. Look inside to the back of the HW tank and find 3 valves close to the inlets of the tank. Open the top and bottom ones and close the middle one. Remember this as this will have to be done in reverse in the fall
 

Rrloren

Well-known member
Don't know where the bypass valves are on the Cyclone but that sure sounds like the problem. Water can't get into the tank if the valves are in the bypass mode.
 

CactusTwo

Active Member
In addition check that the drain plug/ anode rod had been tightened and that EWW!! the gate valves were not left open.
 

boatto5er

Founding VA Chap Ldr (Ret)
Our neighbor has a new 3800 Cyclone and the hot water heater will not fill, Is the hot water heater bypass located in a strange place? I hate to open up the compartment behind the UDC, this unit hasn't been slept in yet.

Surprised the bypass is not located in the UDC like on the Bighorns and Landmarks, but if not, Rich Loren is correct. It would have to be behind the hot water heater. 3 valves, one to shut off cold in, one to shut off hot out, and one to open by-pass connection. On the Landmark there are three screws in the UDC and two in the basement holding the access panel in place. Our panel is large so there's plenty of room to work in that area.

BTW Harvey - great seeing you and Jan in Myrtle Beach last week!
 

JohnDar

Prolifically Gabby Member
Good reason to consider a modification to the basement wall. Fortunately, my UDC has the bypass valving in it, but I wanted quick access in the event of a leak. Makes it easy to check back there, occasionally, and allows access to the converter (I moved it) and the surge suppressor.

View attachment 17416
 

dbylinski

NE Reg Dir Retired
Oh Jon, they are South but you and I are holding down the fort :( while they're enjoying the Florida Sun!
 

dbylinski

NE Reg Dir Retired
Women and Cats do as they please. I'm just relaxing!

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I'm just working and waiting my turn......
 

porthole

Retired
Got it! Thanks, On this Cyclone it is a small inline ball valve.

There should be three of those small ball valves, top and bottom hoses and the one in between.
If it is bypassed the top and bottom are closed, the middle is open.

While you have the wall off consider adding a small RV door or a marine "pie plate" for access.
 
I wished I would have had this information before I headed out on my first trip with the Cyclone 3800. The first night no hot water and it wasn't until the next night when I had a fellow friend that owns a 2008 3950 show me that I had to take the panel off in the storage compartment to get to the back of the water heater to turn the valve to get water to the water heater. This should be something the dealer covers when they go through the unit. I would have never guessed to do that had I not had a friends help. That is a great idea to add an access door. Thanks
 
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