Replacing Seaward S600 Waterheater

[sailcapt340]

I need to replace the Seaward S600 Waterheater on my 2000 340. It has a leak somewhere just draining the water out.
Any advice on disconnecting the two heat exchanger connections in the rear of the unit. As far as I can see, that will be the only place where it is going to get real messy. What do you do to stop the fluid from pouring out, while I'm pulling out the old one and putting in the new one? Or is there not that much that will come out.
Thanks for the advice.

 

[Stu Jackson]

Those hoses are connected to the coolant circuit on your engine. Yes, messy. I don't recall where your heater is in relation to your engine. You can figure that whichever is higher would be the better place to disconnect those hoses first, right?

 

[John T1594]

Water Heater

I have the same boat, same year, same water heater. Last year I had a leak of engine coolant around the heater and it turned out to be leaking around the engine hoses. Tightening the hose clamps stoped the leak. Since this heater is now over 14 years old, I would not be suprised if the tank gave out any day. I plan to use rubber corks to plug the hoses when I disconnect them to keep as much coolant in the engine circuit as possible - that said, I'm sure it will be a mess since the heater core is full of coolant.

 

[Wayne6034]

SailCapt340; John,
I replaced my hot water heater about 2 years ago. It was not as painful a project as I expected. My boat is a 1997 340 and the water heater was original but was not leaking. When you order a new water heater, there are 2 styles. One has antifreeze connections on the front with water connections, mine is other style has them on the rear. I think I drained antifreeze from the engine first so that it would not siphon as much down to the hot water heater when I disconnected that. I drained the little petcocks on the engine with the plastic tubing. Opened the radiator cap. I kept track of how much antifreeze I removed from the engine and replaced same amount. Then when disconnecting the antifreeze hoses from the back of the hot water heater I drained into a container. Had a little trouble bleeding the coolant loop to get hot water to heat. We have talked before and am still enjoying the nice wine stopper you sent! We have moved to the coast. Good luck with your project.

Wayne s/v Wind Drift - Washington, NC

I need to replace the Seaward S600 Waterheater on my 2000 340. It has a leak somewhere just draining the water out.
Any advice on disconnecting the two heat exchanger connections in the rear of the unit. As far as I can see, that will be the only place where it is going to get real messy. What do you do to stop the fluid from pouring out, while I'm pulling out the old one and putting in the new one? Or is there not that much that will come out.
Thanks for the advice.

 

[sailcapt340]

Thank you all....

Stu, John and Wayne..
Thank you for your helpfulness.
Stu, your right, I had planned to do just that.
John, I do have a set of rubber corks and wooden plugs onboard and planned to have them right there with me also. Read on..
Wayne,
Over this winter, I replaced the hoses on the engine, being 14 years old they really needed it, which naturally I had to drain the system out to do.
But, being winter I had no idea that the waterheater had this leak in it, so here I go again. What are the odds!!
The new one is on order, I should have it in a day or two, so by the weekend, I'll be good as new. You come through everytime and thought you would be monitoring this site. What you all detailed is basically what I thought I had to do to make it easier, but I like the input we can get from each other on this site.
Thank you all again for the help.

Congratulations on your move Wayne, glad you like the stopper. You do remember that there was wine attached that until UPS decided to drop kick it to your door step.

 

[sailcapt340]

Update with photos

I thought I would send some photos for anyone who may need to do this job.
If you drain the coolant at the engine you will minimize the loss at the back of the water heater. I drained out about 2 1/2 liters. There is not as much coolant loss as you may think, approximately 2 cups worth at the heat exchanger.
Have rubber corks ready to put in the ends to keep whatever is in the water heater there.
You will need a small pipe wrench to remove the male to male fittings on the heater and reuse them if they are in good shape (or just replace), and pipe thread sealant. Other than some electrical fittings you should be good to go.
Hope this helps.

Oh, the tank had a small rusted pinhole on the welded seam, at the bottom.

 

[MikeZ]

Thanks for posting those photos. I've got a 1996 Hunter 376 with original S600 heater. Doesn't appear to be leaking, but since I've got everything apart as I'm replacing the water pump, figured it's a good time to replace the heater.

I've attached a photo of the cold water connection on my system. It looks like I've got QEST tubing and fittings similar to yours. The difference is that I've got an adapter that screws into the 1/2" NPT on the S600 and provides a 1/2" female thread for the QEST "T" connector.

It's possible that I may be able to reuse this old adapter, but chances are that it's not going to come out too easily and it may not seal well if I install it in the new heater. I would much prefer to find an near-exact replacement - either plastic or brass - that is a 1/2" male NPT on the S600 side and a female 1/2" for the QEST connection. I haven't been able to find such an adapter! Any suggestions?

I guess I could use a 1/2" male NPT coupler followed by a female coupler such as this :http://mypartssuperstore.com/shop/manufactured-homes/female-coupler-12fpt-x-12fpt/,

but space is limited and I'd rather not add a couple of inches to where I make the "T" connection.

Can you tell me what you used to screw into the 1/2" NPT on the S600? It looks like a 1/2" NPT male coupler which should be very easy to find at any hardware store, right?

That still leaves a couple of questions I've had. If you do have a 1/2" coupler with tapered pipe threads, I gather that you get a good seal with the QEST elbow (sku 50-4520)? Do you use teflon pipe tape at the QEST connection or just at the S600 connection side of the coupler? It actually looks like you used some kind of yellow substance so maybe that's not pipe tape.

My other question is if you want the elbow to end up at a certain orientation (your elbows point away from the center of the S600 to get the tubing going in the right direction), does the connection allow you to tighten up to an extra quarter or half turn after achieving what would have been a good seal?

Thanks!
Mike

I thought I would send some photos for anyone who may need to do this job.
If you drain the coolant at the engine you will minimize the loss at the back of the water heater. I drained out about 2 1/2 liters. There is not as much coolant loss as you may think, approximately 2 cups worth at the heat exchanger.
Have rubber corks ready to put in the ends to keep whatever is in the water heater there.
You will need a small pipe wrench to remove the male to male fittings on the heater and reuse them if they are in good shape (or just replace), and pipe thread sealant. Other than some electrical fittings you should be good to go.
Hope this helps.

Oh, the tank had a small rusted pinhole on the welded seam, at the bottom.

 

[sailcapt340]

Replacing the water heater

Hi Mike,
The old connections are in real tight and are brass. Even if you could remove them you'd probably end up crushing the fitting or at least make it out of round. I replaced the old fittings with new brass ones like you want, because I too believe in going all new.
I got them at a local plumbing and heating supply store, but have seen them in small hardware store around the area (1/2 " is right).
I have a set of very old fine tools from my father from his days of auto repair. Some of these tools were specialty type just for hard to get at water pumps etc. I used a thin monkey wrench that allows you to get between narrow places and only has a few teeth so you can't grind away the threads. But you can use a pipe plier and a heavy rag or towel. That will allow you to get a tight fit. Just wrap the fitting with the rag and don't apply to much pressure on the handles so you don't crush the fitting.
Use pipe dope on the threads, not Teflon tape, it comes in a yellow tube available at hardware stores and gives you the seal you need.
You can get the elbow in the proper orientation, just be careful not to over tighten, that's the reason for the pipe dope. It gives you the ability to make small adjustments and still get a proper seal.
Take your time, the job is not hard just awkward to get at.

 

[bamabaxter]

Reviving an old thread, but how long are the heater hoses from engine to hot water heater?