Yanmar 3GM30F Water Heater

[Nichole340]

Regarding My 2000 340 w/Yanmar 3GM30F Engine.
The Water Heater has a leak. Seaward S600.
Do I need to really need to replace the Heater if I don't use it.
I bypassed the heater to winterize the system and now have it just sitting there.
My concern is the hoses from the engine connected in the back of the heater.
Will running the engine without water in the Water Heater be a problem for the engine?
Seems like a needless expense if I don't need the Water Heater.
Do I need to bypass the heater itself by disconnecting the hoses? Or is already bypassed by default?

 

[Tally Ho]

If you never want hot water, I would bypass the inlet and outlet on the motor. Or plug them off.
Then you can remove the WH, and hoses to the engine. This would be the best fix.

You could remove the engine coolant lines from the water heater and connect them together, thereby by-passing the after heater (but maintaining a circuit of coolant). This may be second best option. You can remove the WH if you want.

Third option would be to run it as it is (no water in the WH), engine coolant still circulating through WH.

Not sure I understand last question. Sounds like you have by-passed the water supply to the water heater (so no water in water heater). But unless you also disconnected the 2 engine coolant lines and connected them (therefore by-passing the coolant from circulating through the water heater), then the engine coolant circuit is still in place.

Greg

 

[jssailem]

If your boat is like mine, the builder stuck a water heater (and the associated support lines - electrical and plumbing) between the coolant "Hot" outlet of the engine and the "Heat Exchanger". You can take a hose and attache it to the engine where the Hot hose of the Water Heater is attached and run the other end of the hose to where the Cold side hose of the water heater runs to the Heat Exchanger. This would bypass the water heater all together and return the boat to a more primitive state (without hot water in the tap).

 

[pa391as]

John --- I like your signature! King Oscar was right. Voting age should be 25 then!

 

[pa391as]

I agree with Tally Ho. your best option is remove to hosing between the HWH and the engine, cleanest solution. Why don't you want/need hot water??

 

[Nichole340]

TallyHo,
I have simply removed the cold water feed to the Water Heater. It's drained, electric disconnected to avoid accidental electric turning on at the breaker panel.
The two lines from the engine are still connected in the back.
My concern was running the hot engine coolant through an empty system.

I'll probably reconsider this whole thing come spring commissioning time, but wanted to know the options I had without causing any harm to the engine.

 

[Terry Cox]

Hi Nicole, seems you have a few ideas/opinions to choose from, so nothing to add here. Except, at some point when you decide to resell your boat, the new owner might like the idea of hot water, thus adding to the resale value, FWIW. If it were my boat, I would leave it in.

 

[jssailem]

Nichole, you can run the hot coolant through the water heater. The coolant will heat up the air or residual water in the water heater but should cause no issues. Only thing I see could happen is that the old water heater could spring a coolant leak because it is old. That is why I would remove the water heater from the system as I showed in the diagram. New hose attached straight to the Heat exchanger. Your good to go for many seasons.
Just have to wash your hands in cold water.

 

[Ralph Johnstone]

For those days when nothing goes right .................

 

[splax]

If you are not going to want hot water away from the pier, it is a good idea to connect the output & return ports on the engine to keep all coolant at the engine. It is a relatively common thing for the heater hoses to wear through, where they are routed through the stringers, due to boat motion and leak engine coolant to the bilge causing the engine to overheat. Removing the hoses without spilling a large quantity of coolant can be a delicate operation. Good luck.

 

[jssailem]

Often the Heat Exchanger and the hot out of the engine are high on the engine and can be connected with minimal coolant loss. When removing the hose at the Exchanger the coolant in the line from the engine to the WH will flow out so plan to capture it when the hose is removed.

 

[Secret sail]

I think the water heater helps cool the engine... extra calories going to the water heater!
If you don't want hot water then just put a straight barb on the water pipes at the back of the water heater
Really easy to reconnect the day you want some hot water !

 

[markwbird]

Depends on what's leaking. If the water heater is leaking the fresh water that it heats then, no. You do not have to bypass it. If the coolant water that circulates through it is leaking then you have to bypass it.

 

[Nichole340]

It's the fresh water that leaks. After all is said and done, I'm going to replace the heater. Just didn't want to tackle the job, cost, time. But the right thing to do is replace it.

 

[sailcapt340]

I have the same model and Year boat.
With the same issue....Again!
I replaced my water heater 3 years ago. My 340 is new to me, we purchased it in 2000.
Like I said, I replaced the original water heater 3 years ago and got a little less than 3 years out of the same Seaward model.
The cost is a factor, $350-500 +, depending on where you get it, but look for sales that are coming in the spring for a better deal.
That's my plan.
Believe me, I'm not happy about replacing a 3 year old water heater or anything that only gave me 3 years of service either.
I usually refer this type of complaint to the companies "Cheap Plastic Part Department", but what's leaking isn't plastic, so I'm out of luck there too.
I feel your pain.

 

[sailcapt340]

Just came from my boat and removed the Water Heater ......Again!
I tried to get another maker/model but the area in the 340 just won't allow for it.
I'll be installing the new Seaward tomorrow.
This one had a pinhole leak at the Heating Element. Last time it was at a seam.
So aside from the work and awkwardness of its positioning, it's a pretty straightforward installation.

 

[Boby_Hunter33]

If you install isolation valves then you should have a return valve as well. If there is a leak between the WH and the engine, you close the valves and open the return valve.

 

[Nichole340]

Installed a new Seaward Water Heater today. Easy enough job as cramped areas can be. And I am glad I didn't go with eliminating it altogether.
One question though, they changed the size of the Heat Exchanger Inlet/Outlet dimensions. Same length, just a tiny bit smaller diameter.
My 5/8 inch lines fit tight over the old model, but are loose fitting over the new model. A quick measurement (not a micrometer) showed maybe a 1/16 of an inch less.
Now I have a drip of antifreeze from both lines.

I'm thinking, I could wrap the fittings with teflon pipe thread tape to make up the difference and get a tighter fit when the lines are slid over them. And use two clamps on each line, instead of the original one clamp that were there.

Any thoughts on my approach, or better ideas are welcomed, as I don't want an antifreeze leak in this area!

 

[jssailem]

Not a good idea Nichole. You do not want to have hot coolant spewing about in the boat. You need to either change the hose fitting to one that matches your hoses or you need to replace the hoses.

How old are the hoses? If they are as old as the water heater then the hoses probably do not owe you anything and they should be retired.

 

[Nichole340]

Oh, I agree, don't want that hiding in a corner. The lines, all, to and from the engine were replaced 5 years ago.
They were the same size ID measurement. They fit on every other fitting/connection in the boat. With no leaks, even to the old Water Heater.

The only "new" add on is the Water Heater, same model Seaward S600.
As I can't change the welded fittings in the back of the Heater and the next size "down" in Heater hose won't fit at all, my only option I can see is take up the slack on the fitting.

You just figure it should be a simple swap out, why they reduced the diameter of the fittings defies logic. What did they gain in profits for this move?