water heater woes

[Roc]

That's great Noah, I'm happy for you!!!!

[Stu Jackson]

The simple short answer, which I've spent some time figuring out here at the Catalina Rendezvous in Roche Harbor between visiting with great new friends, appears to be that the water heater loop is, in itself, THE parallel loop.  This appears to be the case because the coolant pump as shown on the linked diagram pulls the water through the block and then outputs it to the HX.  Yes, the short 3/8" hose IS the "bypass" hose, replaced by the heater loop, which is in parallel with the main circuit of the coolant system.  Bypass = parallel.

I was wrong earlier.

[Paulus]

Dave, maybe we will cross paths in the North Channel. 
Paul

[Dave Spencer]

Paul,
Hopefully so. We met up only briefly at Killarney last season.

[KWKloeber]

Ok, here's the corrected coolant flow schematic for the M-25, etc.  This is just the schematic itself, PDF page info is below.



There were several fubars on Universal's Fig 13, including coolant going to the wrong locations and in the wrong direction (what's a few reversed flow arrows among friends?)  No bypass hose wasn't an "error" per se, because IT IS removed for CTYs (but not necessarily removed on engines installed in other boats.)

The corrected page 33 will be inserted in the PDF on the Wiki (Manuals page) if anyone wants to download a corrected copy. Or print the revised page attached hereto to insert in your manual.

Note for those who have WHs connected up, you can see why the bypass hose WAS (past tense) necessary, but is no longer, to keep coolant circulating in the engine block while the TStat (depicted as a butterfly valve) is closed.  The thermostat also blocks flow to the exhaust manifold, so that's why the TStat flange needs a couple 1/8" holes.  If flow isn't maintained before the TStat opens, the exh manifold will develop hot spots (and can go wappy jawed.)

Any questions on why what goes where -- just fire away questions!


Cheers,
-ken

[Stu Jackson]

Thank you, Ken.  Nice work.   Hope your 12 hour trip went well and was successful.

[Bill Shreeves]

     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.

Your posts about a on demand water heater on a C34 piqued my interest.  Is it electric and/or propane?

[scgunner]

       Bill,

         It has electrical controls and connections so you can run it from the main panel. The Seaward unit normally runs on propane, however since I still have the stock CNG system(which I prefer over propane for safety reasons)I asked them to convert it to CNG which they did at no extra charge. It made the combination of 6gal water heater and H2O sun shower obsolete.

[mainesail]

Guys,

Electric On-Demand = Be sure you're shore power service can handle it, most 30A services can't handle even the smallest electric on-demand heaters without exceeding a safe loading range of the service... You're likely looking at increasing the shore service to a 50A service 125V/250V service.

LPG On-Demand = There are no on-demand LPG water heaters I know of that meet the ABYC safety standards. After the Paloma LPG on-demand deaths a number of years ago the insurers have become pretty strict on LPG safety and what they will underwrite. I have had to physically remove on-demand LPG units due to insurance surveys.

[KWKloeber]

Those who have been turning blue waiting with bated breath for the corrected M-25, et al, Owner's Manual to be posted, you can breathe again.
it's online.

THANKS David Sanner!!

Ken

[Stu Jackson]

Those who have been turning blue waiting with bated breath for the corrected M-25, et al, Owner's Manual to be posted, you can breathe again.
it's online.

I'll keep holding my breath, though, waiting patiently for the link.     :D:D

[scgunner]

      Bill,

         As you see whenever you mention tankless water heater it stirs up a bit of controversy. I do recall there being problems with the Paloma TWHs when boaters tried to install them. The problem was the Paloma was a household not a marine application. The unit I chose to install is a Precision Temp(not Seaward) marine tankless water heater. All I can do is relate my experience with my TWH. It's basically been 16 years of trouble free operation since I installed it.

          Concerning shore power, until recently(marina rebuild) I've had a 30amp service, a couple of years ago it was upgraded to 50amp, I haven't noticed any difference. Also, it's a 12v system that runs off of the boat batteries so I'm not sure what difference the shore power would make.

           I'm not up on all the details but the install manual says it's Coast Guard and ABYC compliant. I had an insurance survey done 4or5 years ago and of course they found a few problems but the water heater wasn't one of them.
                                                                                                                             

[Bill Shreeves]

Kevin,
Eh, a little controversy can be a good thing sometimes.  Is your tankless water heater located under the galley sink and how did you handle the power vent?

[KWKloeber]

I'll keep holding my breath, though, waiting patiently for the link.     :D:D

Ok, I'm busted. That was by DESIGN. 
it's not a bad thing for owners to become familiar with clicking around the wiki !!

Especially manuals, ALL of which are linked right off the wiki home page

http://c34.org/wiki/index.php?title=Catalina_34

It's the one UPDATED 5/10/18

[scgunner]

      Bill,

        I had originally considered installation under the sink but it presented some problems; first you'd have to remove the existing water heater, second the compartment isn't well vented, third the vent piping would have to make a fairly long run ending with a new hole in the boat and some kind of vent cover.

        I finally settled on the aft lazeret as the best location. The compartment is big and well vented, the run on the vent piping is only about 3 feet and I was able to use the existing vent on the rear starboard side. I have a stern shower on the transom so I was able to tie into the water lines right there, however if you had to run water lines to the galley it wouldn't be a be deal.

         The bottom line, PrecisionTemp builds a safe, high quality, marine grade tankless water heater. Mine has been providing hot water for 16 years, so far. If you want water hot water all the time it's the way to go, if you're good with a little warm water occasionally, stick with the crowd.