water heater removal

[dpenz]

My original 1988 vintage Atwood EHM6-SM water heater failed recently, so I ordered a replacement.  In two tries, so far I have been unable to remove the old heater.  The unit has two mounting flanges on the bottom, fastened with wood screws to the plywood platform.  The inboard flange, wiring and hose connections are all accessible through the access door on the inboard side of the galley console.  The outboard flange is behind the heater and underneath the sink, hoses and wiring, and cannot be easily reached.  In fact, it is not even possible to see the flange directly.  I employed a borescope and determined that there are two Phillips mounting screws in place. 

Removal requires some sort of tool with a Phillips bit, approximately 14" long.  It is necessary to apply downward force on the bit to prevent it from "camming out" of the screw head, while also turning the screw.  I made up such a tool, but there is so little head clearance under the sink, so far I have been unable to get enough down force on the bit to make any progress.

Everybody replacing a water heater would have faced this problem.  Is there a technique that does not involve removing the sink or the drawer frame under the sink or installing an access opening behind the sink?
 

[MarcZ]

I have replaced my water heater last winter I don't remember using anything special maybe your boat is different under the sink.
I had to remove port side frame and under sink drawer only .
The far or as you describing "outboard" flange screws were removed with impact driver (smaller then drill)  with long philips bit.
From what I remember my left hand was holding a drill (thru space where drawer was) and my right hand was locating screws and setting the bit on them (thru foot pump door)
as you mentioned visibility is 0 but it was absolutely doable by "touch"

[Ron Hill]

Marc : A long Phillips screwdriver does the trick with some gyrations thru the bottom door between the sink and the stove.

The new heater will have a slightly different screw pattern for the hold downs.

A thought

[Stu Jackson]

Don't know if you've seen this:

http://c34.org/hot-water-heater-plumbing-galley-sink-drain-replacement/

Same screw issues.  Looooong screwdriver worked.

[dpenz]

The third try was charmed.     Essential tools were a borescope, very bright flourescent worklight, and a 1/4" ratchet wrench, with Phillips bit and 14" long (in total) extension.  I taped the extension together so that it would not come apart in the bilge.

My heater had three screws in the hidden (outboard) flange.  The hardest part was engaging the Phillips bit into the screw heads, maneuvering the wrench by the handle end, 14" away from the working end, looking into the borescope, which screen seemed to show a reversed image.

I plan to Dremel a slot (or two) into the flange of the new heater, so that it can slide under the screw(s) on the outboard side, and so the screw(s) will not have to be removed in the future.

[KWKloeber]

Another thought similar to what a friend is doing for something similar, screw down an aluminum bar with with washers spacing the bar up enough so the tab SNUGLY slips underneath.  It can't move sideways with the screws and with the tab snugged under the bar you don't need to get in there to tighten/remove screws.  He needs to glass the aluminum receiver onto the hull, but same idea.

If you stick with slots, think about torx or recessed hex drive button heads, or even small lag hex heads to get a 1/4" socket onto them.  Philips were DESIGNED to slip (before the heads shear off.)

It probably doesn't pertain to how yours is mounted, but I had an inaccessible tab when I replaced mine.  I mounted the tab to a cut off strip from a cheap WallyMart HDPE large cutting board (upside-down, recessed-flat-head machine screws,) then screwed down the poly where I had access for screws alongside the WH.

k

[karista]

Replaced my leaking Heater about 6 months ago. I decided to install the new heater about 1" forward towards the door to allow easy access to the rear tab screws. This made installation a lot easier than the removal of the old heater. The new Seward heater rear hose connections are spaced differently than the original Attwood so it required a cutout of the wood support platform to allow the engine hoses to be connected.

[Stu Jackson]

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The new Seward heater rear hose connections are spaced differently than the original Attwood so it required a cutout of the wood support platform to allow the engine hoses to be connected.

In my recent Tech Note about my heater replacement, I recommended that you add a few feet of 5/8" hose to the heater itself BEFORE you put it back in.  This makes the connection to the hoses from the engine much, much easier. 

For C34IA members:  http://c34.org/hot-water-heater-plumbing-galley-sink-drain-replacement/

"The installer of the old heater had done a smart thing: He had connected a few feet of 5/8″ hose at the back of the heater so that the connections to the hoses from the engine would be easier to access around the wooden shelf that holds the foot pump and the water pump under the galley drawers. ... Before I slid the new heater in, I installed new elbows into the hot water out and cold water in connections, and connected the two hose extensions to the back of the heater which made the connections to the engine hoses much easier."

[Jon W]

What's the orange cable and plug above the water heater for?

[Stu Jackson]

Jon,  the cable is red and is the output of the alternator, run under the engine and over the heater door inside.   What looks like a switch on the left is the Power Post Plus, my NDP "bus" - I used a post instead of a strip-type electrical fitting.  It carries the 2/0 from the I/C and is extended with 2/0 to the house bank and fused.

[Jon W]

Didn't realize that was a photo of your boat. Looks orange in Bernd's photo.

[Stu Jackson]

Jon, Now I understand, thx for clarifying,