Water Heater Advice

[jbenagh]

As part of a lot of other work this winter I plan to replace the hot water heater on Christine C. This will make some more room in the locker and allow for 1-2 additional house batteries in a better box. We do use the hot water fairly often while cruising to wash dishes and even shower so I will not remove without replacing. I plan to remove the existing heater from the starboard cockpit locker and locate the new one under the cockpit sole (thanks Steve Laume for that idea).
What do you all think about the differences between the Isotemp Slim 15 Marine Water Heater and the Isotemp SPA 15 Marine Water Heater? They appear to be identical except the former has a stainless steel housing and the latter has plastic and is roughly $300 cheaper. Since it will be under the sole no one will ever see it so what is the advantage of the Slim version? Am I missing something other than aesthetics?
Jeff

[Capt Hook]

From what you said it sounds like the advantage is the stainless steel housing.

[Jim Walsh]

The all stainless one is slightly slimmer. I've had one for a few years. Works fine and slipped right in through my cockpit locker without a hassle. If the slightly larger profile will fit, go with the one with the plastic exterior. They both have stainless tanks so should have the same life expectancy.

[Bob Ohler]

Jeff, please keep us posted on the progress of this project. I am sure that there are many of us interested in how this remove/replace project goes together. I like the idea of putting the heater under the cockpit sole. Hopefully, you will post pictures along with your updates.

Thanks and fair winds.

[Steve Laume]

Measure a couple of times to be sure the thing will fit.

I used the 4 Gal Isotherm and it fit right in there but without much room to spare. I mounted it on a platform with the long axis oriented perpendicular to the center line. The diameter had a bit of room to spare but the ends were pretty close. I have been very happy with the installation and the heater. It heats up fast and will hold for 24 hours or at least until morning if you ran the boat to anchor the night before.

One other thing to consider is making the platform a little longer and moving your heat exchanger onto the front end of it. Raven has a Universal engine and I had to loosen the hose clamps on the engine mounted bracket to be able to access the zinc. It is now much easier to get to so I check the zinc a bit more often.

After I got the water heater off of the battery shelf I was able to move my two group 27 house batteries all the way forward. I cut off all the un needed shelf to enlarge the locker area and make it much easier to get at the cockpit drain seacock. I found enough room to make another little platform behind the seacock and below the original battery shelf for my group 24 start battery. I felt this was the best I could do as far as moving all of those heavy items as low and as far forward as possible. At one point I had the start battery under the cockpit sole but once I installed the heater I moved it to it's current location. I feel it is far better to have the water heater in a hot place and the batteries in the cooler cockpit locker.

Sounds like you have your work cut out for yourself this winter, Steve.

[jbenagh]

Got around to trying out the fit of the new water heater today. I purchased the Isotemp SPA 15 with the plastic shell. It looks like it will fit nicely! Thanks, Steve Laume, for the idea on the relocation!

From the starboard locker the fittings look accessible with space to move the tank up for better access (the underside of the cockpit sole is at the top of the picture):

From the port locker I can still access the seacock with plenty of room for maintenance:

There is still decent engine access, better than it looks form this picture, actually:


And, as a side benefit, it looks like a lot more room for the batteries and now they can both be out of the way under the bridge deck. Sorry I don't have a before picture but the house battery (left) was at about a 45 degree angle) and the started battery was mounted over the tie down strap in the picture:

There's actually even more space if I move the ground buss bar and Victron shunt. And it looks like there is space to build a real battery box here, out of the way of the rest of the locker. It might even fit two house batteries which would help enable radar.

Next step is building a pattern for the mounting on the hull and checking with the steering gear installed. Unfortunately I forgot all that at home today so I couldn't check as well as I would have liked. It will be more accurate to check with the mount for the heater mocked up anyway.

Jeff

[Steve Laume]

Things are looking good. What fun it is to work down there.

Now is the time to cut away a bit of the upper shelf that sticks out to the left of your battery. You will thank yourself every time you go to service that seacock, Steve.

[jen1722terry]

Good advice from the others on the Isotemp install.

We put one in last year, following Jim Walsh's sage advice, as we have the same model CD that he owns.

We measured carefully and decided the plastic 4 gal. model would just fit and save some $$. The install went pretty well on the shelf in the aft of the port locker where the old Raritan lived (and leaked). Getting the aft, outer mounting bolt in was a bear, but it's on. We took the opportunity to examine and replace some of the engine hoses that run back to the heater.

We did encounter one problem when we connected all the water hoses: in tightening one of the hoses ( the one that runs off the fitting with the temp control valve) we accidentally moved the factory compression fitting just a bit, which caused it to leak. Gentle re-tightening didn't help. The joint can not be disassembled as designed. A call to the manufacturer led us to work some teflon tape in the joint with a narrow screwdriver and then retighten it. It's tight, and let's hope for the duration. The joint could have been designed better IMHO.

The heater works fine, but do note that Isotherm advises draining it completely for the winter, rather than filling it with antifreeze (may be a warranty issue).

Plan on a full day or more for the install, so you can take your time. Also plan on a bit of a sore back.

Good luck

Terry

[Steve Laume]

I plumbed my heater with a by pass line and three valves. There is a line that runs between the inlet and outlet to the heater with a valve in it. There is also a valve on the inlet and the outlet. To winterize I shut off both valves to the heater and open the one in the connecting line. I can then drain the heater and pump antifreeze through the plumbing without involving the heater tank.

It works very well and saves a ton of antifreeze compared with trying to winterize the whole tank with the stuff, Steve.

[jen1722terry]

I like that set up, Steve. What I did this year was just disconnect the inlet and outlet and connect them, but this will be much easier. Thanks for sharing.

Terry

[jbenagh]

Warm weather has meant epoxy time. Here's the shelf I made from Coosa & glass with a test fit of the shelf and the heater. The hull is pretty rough down there so I need to pick up some paint stripper; it would have taken forever with the wire brush. I'll install this over the weekend. Note that the steering gear is all removed as part of the cockpit sole project I talked about elsewhere.

[Maine Sail]

The heater works fine, but do note that Isotherm advises draining it completely for the winter, rather than filling it with antifreeze (may be a warranty issue).



Terry

This is a proper winterizing procedure for every marine water heater not just an IsoTemp... Trying to dilute the 4-6 gallons of water in the tank, with PG antifreeze, takes GOBS more than 4-6 gallons of antifreeze to have adequate freeze protection..

Almost without fail each and every spring I get to replace frozen and split water heaters because an owner assumed you could just pump -50 PG through the system and when you "see pink" call it a day.... I replaced a frozen and split IsoTemp last spring for this very reason... Cha-ching $$$$$..... You should drain & by-pass a water heater for winter...

[jbenagh]

Here's the Coosa & fiberglass shelf for the water heater all epoxied in using 10oz cloth strips on each outside end. The shelf was also bedded in silica-thickened epoxy. It seems super strong. Also it seems to have adequate clearance (about 3/4 to 1in) to the steering quadrant; I did not get a picture of that as I was doing a lot of adjusting during that reassembly. My next post should show the final product!

[Northstar1014]

Look good, Jeff.

Will you be working on the boat this coming weekend?

I am 2 boats down from you in the yard - will come over and say hi.

Ted

[jbenagh]

Ted,

thanks for stopping by and offering assistance yesterday! It was great to talk to you.

Jeff