water heater woes

[mdidomenico]

That's what mine looked like(2nd set of pics)before I junked it. Do yourself a favor go tankless, you'll never be sorry. You'll have as much hot water(not warm)as you can use and you won't have to run the motor to get it.

tankless on a boat?  that's the first i've heard of that.  who makes such device?

[Ron Hill]

Guys :  Eliminating the water heater (loop) has been mentioned on this site a few times.  Simply run a short hose from the water pump to the thermostat housing (replacing the existing hoses that go to the water heater)!

I first heard about that when I met a Erickson owner in Florida that did that to his M25 engine.  Even in Fl.  warm waters he had no problem!

However, I wrote a Mainsheet article Tip that stated - "If you ever get into a situation where you have an overheating engine and MUST run the engine for a short time (emergency) - turn on the hot water in the galley and head fausets fully.  Then the WH will help act as another heat exchanger". 

A thought

[Stu Jackson]

A question:  Before you removed it, did you still have the heating loop from the engine functional?

presumably the loop itself was still intact.  i was able to run the engine during survey and winterization without a loss of coolant or anything.

i did pull the hoses between the water heater and the engine.  they were in really rough shape, but still "intact" enough

i never did fill the fresh water side of the plumbing stuff, figured there wasn't any point since all the hoses and tanks needed to be replaced or cleaned

md-

Thanks so much for your reply.  Understood.

For feedback from me, my friend investigated further at his engine. 

He just explained it to me this way: 

"We've had this boat for about 2 1/2 years now, and here in the PNW we're sailing only half the year.  Kinda like folks back east who have to pull their boats, but we stay in the water.  I looked at the engine and the hose between the thermostat housing and the top of the water coolant pump (M25 engine, 1983 C36).  There was NEVER a connection to our water heater, which only heats by electricity!!!  [There IS a hose between the T housing and the the top of the coolant pump.  Just like the diagrams in the manuals and the TOAD website show, and that Ron has told us, repeatedly about.] Oddly enough, my wife simply never told me about it, and she's the one in charge of the galley - without being a galley slave."  :D:D

So folks, the "big problem" for my friend has been solved completely.  Heck, if it ain't connected...

He thanks you all for your help. 

[KWKloeber]

It was 1986 when the factory removed the bypass hose and connected the WH. The c-30!Mk-II was the switch.   

ALL pre 86 came with the hose still in place.

K

[scgunner]

     mdid,

        I got mine from Seaward Marine, there are a couple of other companies that also supply marine quality tankless heaters. You probably haven't heard of them on boats because they don't seem to be very popular with the boating community in general. I think boaters are afraid they will explode or catch fire or something. I've had mine for about 15 years, like any other piece of equipment that's properly installed and maintained it's performed flawlessly. Comparing it to a typical 6gal water heater is like comparing a Ferrari to a Yugo.

[Stu Jackson]

Stu

The link was direct to MY post, explaining to Noah what that hose is, and how the WH loop works. Take a read thru it.

On all y'alls boats the bypass hose was removed from the OEM M-25//xp engines and the WH put into a parallel loop, BASICALLY replacing the OEM KB loop created by the short bypass hose.  It's just a MUCH LONGER loop and has a WH coil in the middle of the loop. See my pics showing the hose that your WH loop replaces.

Even on the early C30 M-25s, the Hx was never in series with that bypass hose. The short hose existed OEM Kubota on the early engines  and at some year? CTY changed to the setup the MkII C30 and your boats have. (I made that mod  to my Mk-I /  M-25).

I'm not sure which manual you're referring to?  Parts? Owner/Ops? Service?
The pic I pasted (parts manual) in my post shows no Hx in series. The pic SHOWS the bypass hose which is CORRECT.  That's OEM Univeral and Wb.
CTY is the one who scraps the bypass hose when they plumb  to the WH.

That WH loop replacing the bypass hose is WHY we get H W so quickly. Circulating coolant is heating the water because it's NOT in series w/ the Hx, and H W doesn't depend on the thermostat opening.

In effect one can disconnect the WH and plug both hoses (not have to connect them together) and won't overheat. BUT it's dangerous because of the "hot spots" I explain in my other post.

Make sense or did I muck it up further?


-K

Ken, 

I have read it.  I started that thread.

No muck, it's just that I think there may be a "disconnect" between the application of the words series and parallel.

The short 3/8 inch "bypass" hose, between the coolant pump and the thermostat housing provides a pathway for the coolant to circulate as shown on the referenced flow diagram from the engine manual.  When the water heater replaces that short hose, it is in series with the entire coolant flow circuit, not parallel.

The parallel circuit you keep mentioning may well be the internal thermostat bypass which operates before the thermostat opens.  Could this be your parallel item?

If one examines Bob Kuba's excellent tech wiki article about adding a bus heater core & fan, it clearly shows that the "exterior" loop HAS TO BE in series through  both the water and bus heaters for the coolant system to continue to work.

http://c34.org/wikiwp/?rdp_we_resource=http%3A%2F%2Fc34.org%2Fwiki%2Findex.php%3Ftitle%3DCabin_Heater

Stu

Ok I see —. In the OPS manual.

The FIG 13  is wrong, it has a couple flaws in it. 
When I get time I will 'adjust' it and post the correct flow pattern.

It doesn't show a WH so one can't infer anything about the loop from that fig.

Sure, one can simply "show" the water heater:  between the coolant pump and the thermostat.   Bob Kuba's diagram is pretty clear on that, as is the plumbing diagram in the C34 boat manual, which is the basis for Bob's diagram.

Ken, if you don't have time to correct and show the flow pattern you mention, perhaps you can just describe where it is wrong.  That may help to clarify this parallel vs. series issue.

[KWKloeber]

Stu

You wrote
""Page 33, Figure 13 in the M25 manual shows that the water heater would be in SERIES with the coolant circuit.  ""

That is incorrect. The WH loop PARALLELS the coolant (ie, Hx) circuit.

As I said below. Fig 13 is WRONG.

K

[Stu Jackson]

Ken,  I know you said it was wrong.  All I asked was to explain why.

From Science Digest:

"Pipes are said to be in series if different lengths of pipes of different diameters are joined end to end with the entire flow passing through all pipes. Sometimes two or more pipes are connected so that the fluid flow splits among the branch pipes and eventually combine downstream into a single pipe. Such a piping system is referred to as parallel pipes."

In series piping, if ALL OF THE WATER goes through all of the pipes without any parallel branches, it is a series piping system.  We have ONE pump, which circulates all the coolant water through the entire system:  pump >> water heater >> thermostat >> manifold >> HX >> back to pump.

It is one continuous "pipe" and the water flows through the whole system equally.  There appear to be no branches.

At least that I can see.

That is why I'm asking.  That's all.

[KWKloeber]

I will correct the figure.   That will be easier and quicker than trying to describe the coupke errors in the figure, and the back and fourth trying to further clarify it.   

I know the effin difference between series and parallel, Stu. That's not the "disconnect". The disconnect is that Universal couldn't publish an accurate flow schematic of its own effin engine!!  You know yourself that the Hx doesn't connect back to the engine block. The 7/8" hose connects to the 1" hose nipple on the coolant pump.

That's only ONE of the couple errors.

K

[Stu Jackson]

Thank you.  No need to be rude.

[Noah]

In a random attempt to lighten the mood...(and bring it back to me) I RETIRED TODAY!!! Lots 'O sailing ahead! 

[Stu Jackson]

Congratulations, Noah.  Well deserved.  Now, as I've learned, is when you really get busy. 

[KWKloeber]

Stu

I don't know what's rude. 
Maybe continuing to insist that when I say parallell, I really mean series?  Or that when in the first answer I explained you can't rely on that figure to understand what's going on, but need to be scooped on how water flows they pipes?

you asked what's wrong with the fig and I gave you one example of several errors. There's more than I can explain.  I'm on the road and have 12 hours ahead of me otherwise I'd pull over and revise the figure to solve this emergency. What I am trying to tell you is I know Universal engines and when I state something is correct or is wrong, its not on a whim or without thought. Just go with what i am saying for now.

Oh, yeah-  the cabin heater article has nothing to do with the engine cooling loop. There's no Hx in his schematic, correct?  Only the WH loop, which parallels the engine cooling circuit. The cooling circuit isn't shown in his diagram.

[Paulus]

Ken, you seem to be an intelligent person and have provided us with lots of things to consider.  But, I wish you would get out of bed on the right side.  Reading through a few posts this morning, i came across the following; criticism of CTY(rather lengthy),  POs, "Engineer guys" and  "Jesus H. Christ guy". 
"if you can't say something positive about someone, then don't say it at all".  This was one of the rules my parents raised me by(among many others).
Have a good day.
Paul

[Dave Spencer]

Welcome aboard Noah!  This will be my second summer of retirement and I'm looking forward to 8-10 weeks aboard cruising Georgian Bay and the North Channel. 

Ken,
I echo Paul's eloquent comments. I value the knowledge you share but...