Water Heater Removal

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nveater

Veteran Member
Joined
Nov 4, 2021
Messages
43
Vessel Name
Pathfinder
Vessel Make
Mainship Pilot 30
I need to replace the hot water heater on my mainship 30 pilot. As you can see by the pics I will need to remove the exhaust hose to gain access. I was wondering whether anyone has done this ? Any tips or cautions Thanks water heater 2.jpg

Water heater.jpg
 
Yes that would be more of a pain !
 
I know of a boat where they had to remove one of the engines to repair the genset. And it was a production boat.

Boats are designed by "designers" to make them look good, then it's up to engineers to make all the parts fit. That's a PITA but it could be much worse.

Why are you replacing the water heater? If it's just not making hot water, the element or thermostat is probably the problem and either should be fairly easy to replace.

If it's leaking (and it's not just the TP valve which is also easily replaced), that's another story. Remove what's necessary but take photos so you can put everything back the way it's supposed to be.
 
rwidman: The previous owner was unsure of the cause- but he also cut the lines coming to and from the heater (not the heat exchanger lines). I would suspect the heater element= it's an ATwood from the 90s and I cannot find a heater element to fit (Part # 91580) . I think I am destined to replace the unit
 
nveater said:
rwidman: The previous owner was unsure of the cause- but he also cut the lines coming to and from the heater (not the heat exchanger lines). I would suspect the heater element= it's an ATwood from the 90s and I cannot find a heater element to fit (Part # 91580) . I think I am destined to replace the unit
Click to expand...

You are looking at a big job to possibly correct a small problem. You can test the element with a continuity tester. Testing the thermostat is just a bit more involved but it can be done.

I suggest removing the heater element and taking it to a plumbing supply store in your area. A good counter person should be able to match it up with something that will fit and that will work. Same for the thermostat if that turns out to be the problem.
 
Thanks that sounds like removing the cover plate and element and testing it should be my first step- I appreciate the feedback !
 
Neither element nor Tstat are very expensive. If one is bad you might consider doing both while you are at it.
 
Yes thanks good idea- there is also a reset button on this water heater and while I would assume that the PO hit that I will check that as well. Replacing or re attaching the cut hose(s) maybe a pita as upon cursory look I can't even see them
 
nveater said:
Thanks that sounds like removing the cover plate and element and testing it should be my first step- I appreciate the feedback !
Click to expand...
You can test the element without removing it but you must remove one of the wires.

Be sure to turn off the power first. ;)

BTW: One of the best ways to burn out a water heater element is to drain the tank with the power still on. Without water to cool the element, it will burn out in a minute or two.
 
We looked at a boat where the water heater was drained and turned on. I was in the engine room and heard a sizzling sound. It was the water heater. I turned it off. We did buy the boat. I assumed the water heater element would have to be replaced but it was still working when we sold the boat 8 years later.
 
My heater element was fairly standard. I just bought another one at Lowe's and replaced the old one. That solved the issue (random hot water), so I tossed the old one. Probably should spend $14 to have a spare.
 
nveater said:
Yes thanks good idea- there is also a reset button on this water heater and while I would assume that the PO hit that I will check that as well. Replacing or re attaching the cut hose(s) maybe a pita as upon cursory look I can't even see them
Click to expand...
If it has acreset I'd also replace that... especially if it has difficult to get at.
A few years back I had a water that didn't work on my motohome. Of course the heater, Tstat & reset were all on yhe backside requiring removal to fo anything. PITA removing wiring and hoses. When diagnosed it was only the reset that tripped... I didn't want to reassemble only to find it not working after a short period. Replaced all 3 and never had an issue again.
 
Most of the time a leaking tank on a water heater in a boat produces a rust stain on the deck the heater is mounted to. Not just a bit of rust stain but a stain that makes it clear water was actively leaking from the unit.

It could have minor condensation rust around the case but the tank could be ok.. hope for the best!
HOLLYWOOD
 
I don’t think anyone has mentioned the anode. Most water heaters will have one that should be checked and probably changed.
 
The first thing I would do is take 2 90 degree elbows which match the size of your cooling hose. I would then get about 1 foot of the same sized cooling hose. Clamp the two elbows to the piece of hose. Now you have a antifreeze bypass.

remove the first hose from the water heater, raise it up and connect the bypass. Repeat with the other hose.

Now, you can still run the engine while the water heater is disconnected and you won't loose any antifreeze.

NOTE: My water heater is lower than my engine. When I disconnect the AF lines to the water heater, the AF will drain into my bilge.
 
Folks, I appreciate the great comments and sage advice. While I probably will not undertake this until the Spring (or at least in slightly warmer weather) here is my current thinking: 1) I have to remove the exhaust hoses I believe to get at the water hoses the previous owner cut. At this moment I can only visualize the hot water side piping. 2) I believe that will have to remove or at least detach the water heater from it's base to get at the cold water hose 3) If I have gone this far the current water heater is at least 23 years old, should I not replace ?

I will post pics when I undertake this mission and I still welcome all thoughts and comments both pro and con
 
Some of the smaller Atwood heaters didn’t have a settable thermostat, they had a thermal disc “snap switch.” Cheap and easy to replace but probably not the problem. I had one that would regularly expel water out the relief valve on the first heat cycle from cold. Atwood has instructions on how to burp the tank but it never made a difference for me.
 
Water heater

nveater said:
Folks, I appreciate the great comments and sage advice. While I probably will not undertake this until the Spring (or at least in slightly warmer weather) here is my current thinking: 1) I have to remove the exhaust hoses I believe to get at the water hoses the previous owner cut. At this moment I can only visualize the hot water side piping. 2) I believe that will have to remove or at least detach the water heater from it's base to get at the cold water hose 3) If I have gone this far the current water heater is at least 23 years old, should I not replace ?

I will post pics when I undertake this mission and I still welcome all thoughts and comments both pro and con
Click to expand...

I owned a 2000 MS Pilot with the same set-up as yours. The water heater also failed as evidenced by a rust stain and significant leakage when I was commissioning the boat in the spring. I replaced the water heater with a SS model of the same size. Yes, the exhaust hose needs to be removed and while you are at it you should replace the exhaust hose with new. It’s not that expensive and will save you from doing it later. If you are doing all that work I would install a new water heater instead of trying to salvage the old one. At w3 years you are lucky it has lasted as long as it has without problems.
 
Capt Mike said:
I owned a 2000 MS Pilot with the same set-up as yours. The water heater also failed as evidenced by a rust stain and significant leakage when I was commissioning the boat in the spring. I replaced the water heater with a SS model of the same size. Yes, the exhaust hose needs to be removed and while you are at it you should replace the exhaust hose with new. It’s not that expensive and will save you from doing it later. If you are doing all that work I would install a new water heater instead of trying to salvage the old one. At w3 years you are lucky it has lasted as long as it has without problems.
Click to expand...

A water heater should last way longer than three years. Way longer.
 
nveater said:
Folks, I appreciate the great comments and sage advice. While I probably will not undertake this until the Spring (or at least in slightly warmer weather) here is my current thinking: 1) I have to remove the exhaust hoses I believe to get at the water hoses the previous owner cut. At this moment I can only visualize the hot water side piping. 2) I believe that will have to remove or at least detach the water heater from it's base to get at the cold water hose 3) If I have gone this far the current water heater is at least 23 years old, should I not replace ?

I will post pics when I undertake this mission and I still welcome all thoughts and comments both pro and con
Click to expand...
I may be missing something but from yhe pic it looks like everything is accessible from the front side. I see what looks like H & C water line and at least one engine cooling hose and the electrical cover.
Can't you access everything by reaching over the exhaust?
I'd at least pull the elec cover and try to pull the element to match w a replacement. If there is apparent tank leaking that's a whole different story but would try repairs in place if at all doable.
 
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