RE: Wolter water heaters / engine heated water

Newsgroups Archive Prior to 2025
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Persistence came with a broken Wolter (heating tubes had been split open by frozen water). I silver-soldered the tubes and got a few years out of it, but in due course it opened up again – I obtained several discarded units for parts and tried to nurse it along, but the age of the parts became an issue.

I then installed a Volvo hot water tank that heated water from the engine and from AC at the dock. It worked well, but engine heat did not seem to bring it up as well as the AC – I needed to run well over an hour to get it hot for a shower and the dishes, and by morning at anchor it was tepid. But MUCH better than nothing.

When the Excel 1.6 gpm heaters came along I installed one in the same mounting area as the Wolter, and vented it using the existing vent. Some issues with draft (would not stay lit), but I added a fan (like the Wolters had) and that helped a lot.

I then integrated the two systems so I could use the tank water (more reliable for showers!) when available and switch over to the demand water when I am sitting at anchor. I am pleased with the option, but not sure I would have gone to the engine heat had the Excel been available.

Bill Baxter

Persistence NS30 #507

Penetang, ON

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Bill, what fan did you use. I would like to install one on my Excel. Wasn’t sure which fan could take the heat.

Tim,
La Reina came with a Wolter water heater. It died of old age and I replaced it with an Excel. The Wolter uses an igniter instead of a pilot light. When the tap is opened and water starts to flow the igniter is activated and the propane valve opens. Once a flame is lit the igniter shuts off. They require a chimney that is to be a minimum of 12” or 16” tall. I can’t remember which. If the chimmey is too short a back drag can put the flame out. I believe this is why later versions had fans installed. I believe there was an explosion with a Wolter and a subsequent law suit that ended the company.

There may have been an individual who serviced and provided parts for them for a while afterwards but I believe he is no longer in operation.

The Excel is similar in concept to the Wolter but it also has an oxygen depletion sensor that will shut the system down. The Excel is called ventless but I don’t believe insurance companies will accept a ventless system on a boat. I used the vent from the Wolter and added a CO detected in the head where the heater is installed. The surveyor ok’d the setup and my insurance company has accepted it as well.

I don’t think there is any doubt that the engine and AC heated water tanks are safer than the propane fired on demand heaters. I believe as my Excel heater is set up it is as safe and maybe a bit safer than the old HilleRange stove and oven that came with the boat. The Stove does not have a thermocouple sensor so if the flame goes out the propane keeps flowing. The stove would not be approved for installation today but it is “grandfathered”. The oven is worse because it confines the propane and it is harder to see if the flame has gone out.

Mark Powers
La Reina 26C
Vancouver, B.C.

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Hi Mark,

The plastic fans certainly cannot take the heat inside the unit (don't ask). I ultimately used a small (yet noisy!) 12V computer-type fan wired just outside, underneath the outboard aft corner and wired it up to the circuit originally used by the Wolter to energize the igniter. Creates draft right up thru the unit.

It means I have to flip the 'blower' switch at the panel near the companionway every time I want to use the Excel -- have been looking for a small 12v surface mounting switch (with no luck) at RV and auto parts places so I can energize the bower at the galley.

Bill
Persistence NS30 #507
Penetang ON

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Bill,
If I understand correctly you are blowing air up through the heater rather then sucking it up on the exhaust side?

I had thought of trying a bilge blower fan in the exhaust stack but thought it might not stand up to the exhaust temp.

Thank you.

Mark Powers
La Reina 26C
Vancouver, B.C.

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I’ve got an Excel propane water heater on our (new to us) NS26C. From reading the manual, it appears that one requires “active ventilation” in the boat, which we don’t have. Again, from what I’ve been reading, a solar/battery powered vent in the head would do well in this regard. There is no need for a steel vent connected to it directly.

Just my novice opinion/thoughts.

John/NS26C Kingston ON.

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Hi John,

You may well be right – but when it comes to CO I take a belt-and-suspenders approach. Most Excels are installed where a vented water heater was previously installed, so venting is easy. In my case, I added a small computer fan underneath the Excel housing to help with ‘active ventilation’.

Bill Baxter

Persistence NS30 #507

Penetang, ON

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Hi Mark,

Yes, I am blowing it up from the bottom left front corner with a small 12V computer fan wired to the grill. I did this to improve draft, as at times the heater would not stay lit. I also got a 12" stack extender that I can install if conditions persist and the heater gets persnickety. But for the most part, the little 12V fan does the job reliably.

I bought a range of fans, some much larger, to try in the stack, but I found the fried results inedible.

Bill
Persistence NS30 #507
Kingston, ON

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If anyone is interested in my 1990 Wolter and willing to pay shipping, its yours, free. It has been in my garage for two years. First come first served.
Can be picked up in Connecticut.

Bob Hindle
Jenny
NS 33 #60 1990

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Bob,

I'm replying to your post from last spring regarding an old Wolter unit sitting in your garage. Is this still available? I just commissioned my new to me 30U and the Wolter heater is leaking. It appears to have been repaired numerous times before by resoldering the tube joints so a replacement seems like a better option. If your old Wolter is still available and in good condition I'd give that a try before purchasing a new Excel which sounds like the recommended new replacement option by most.

Thank you,
Greg Doyal
NS30U #516 Challenge
Grosse Pointe, MI

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Greg: Consider going to an engine driven unit. I have a lot of info if you're interested.

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

~~~~~(\_ ~(\_ ~(\_~~~~~~~~~~

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As I have before I’ll second Joe’s recommendation of a marine water heater.
Those propane heaters on boats are more dangerous than COVID-19.
You won’t see propane water heaters sold at Defender. West Marine or other marine parts and pieces suppliers.

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Sorry Greg, I tossed it when I insulated the garage last winter,
That said, I do have some comments about propane HW heaters. In September 2018 the old Wolter was getting fussy and I decided to replace it with an Excel.I decided to have the yard install it, mostly because I didn’t want to deal with propane. The first time we tried to use it it wouldn’t light and after a few attempts the bilge exploded in my face. It turned out a faulty installation job, nothing to do with the heater unit. So it all led to an investigation by two opposing insurance companies and a detailed examination by two marine fire inspectors, fascinating I might add. They all knew other and had many stories to swap back and forth. Apparently this type of event is far more common than I imagined. I’m no expert but when they disassembled the nearly new unit, which was not damaged, they were not impressed. I don’t feel I should say too much as a layperson but I ended up getting an engine heater. I did contact the local, well respected marine propane dealer and received a scolding like I was a kindergarten student, “There is no place for a propane hot water on a boat”, he said as though only a dope would ask.
That’s it.

Bob Hindle
Haddam Connecticut

Jenny
1990 NS33 #60

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I find the discussions about propane water heaters interesting.

We know that propane on boats creates hazards. 1: Propane is explosive and it is heavier than air so if there is a leak it will sink in to the bilge where a spark can ignite it an cause a fire and or explosion and 2: Burning fossil fuels produces CO which in high enough concentrations can be fatal. Properly installing, maintaining and using the propane appliances will reduce the risks. Proper installation includes CO detectors and propane sniffers.

Hot water heaters that run off of a heat exchanger from the engine cooling system are clearly safer than propane fired systems.

Adding 110V shore power to a boat to heater water introduces a hazard as well. The primary hazard is electrocution. Properly installed, maintained and used the risk is very low but still present. I do believe the risk is lower than from propane.

Many of us have propane fuel stove and ovens on board. The hazards from propane are the same whether it is used to feed a water heater or a stove. Some people install on demand propane fired water heaters in the head on the boat which is generally a smaller space than the galley. The head will require proper ventilation. The propane solenoid should be shut off except when an appliance is in use. The head door and port should always be open when the heater is in use. This increases the risk of CO poisoning. Some people further will take a shower in the head with the door closed while the propane heater is running. This creates a smaller confined space and a greater hazard.

I am hoping someone can explain to me why a properly installed, maintained and used propane water heater creates a greater hazard than a properly installed, maintained and used propane stove or oven.

Many years ago, I think in the 70’s or early 80’s an attempt was made to use natural gas fired instead of propane on boats. Natural gas is lighter than air so rather than collecting in the bilge, natural gas will usually rise and exit the boat through open ports or the companionway. Therefore there is a lower risk of explosion. I believe the attempt failed because it was too difficult to find places to refill the natural gas tanks.

Ward,
are you related to a Gary Woodruff that races sailboats on Niantic Bay? https://www.theday.com/article/20150813/SPORT04/150819629

Mark Powers
LA Reina 26C
Vancouver, B.C.

On Thursday, March 28, 2019 at 7:36:29 AM UTC-7, Bill Baxter, Persistence, NS30 #507, Penetang, ON wrote:

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Hey Mark;

I did purchase a propane detector, with its’ own automated propane shutoff valve, and 1 remote propane sensor. It can handle 3 in total.

These boats were built in a time when detectors were not common. When done, we should have propane, CO, and fire alarms. (the fire extinguishers were refilled last spring for our first outing; they were 10 years out of date)

Now to actually get down to the yard to install them; not likely for a few weeks. :expressionless: (boats’ still in the shop, no guests allowed in - COVID-19 restrictions. C’est la vie)

JohnS
NS26C, 046,

souped up with a new Beta 20,
Kingston ON.

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I agree with Mark that a properly installed propane demand water heater (particularly a newer model) should be no more dangerous than your propane range.
Both Mark and I have the Excel heaters which are several steps ahead of the old Palomas that were originally installed in (many, most, all?) our boats.
They have oxygen sensors to detect depleted air quality and they are piezo ignited by water pressure drop instead of having a pilot light. If they don’t light, they shut down the gas.
I have been around boats and marinas my whole life and have only seen one serious propane incident personally. It was caused by a coincidence of several negligent actions. I have heard of and witnessed many more fire/explosion situations from gasoline but there is almost always negligence involved.
For me the bottom line is that It is the negligence that is the dangerous part.

Rant over....

Paul M
NS30U #211, Sandpiper
Cowichan Bay B.C.

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Hi Mark,

Gary Woodruff is my son. I used to race Ensigns too; for almost 30 years. The Ensign is a great boat.

On the topic of propane water heaters, the manufacturer’s instructions usually indicate, “Do not install this product on a boat.”

Unlike a propane range, the water heater can operate without much supervision. The original ones were drafthood vented appliances. Drafthood vented appliances require 5’ of vertical vent above the flue outlet of the appliance to reliably vent . You can’t get that height on a boat.

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Every cruising boat should have a propane detector, CO2 detector and a smoke detector. Mine actually has more than one of each type for redundancy..

Would not leave the dock for an extended cruise without them..

Cheers

Brian McCuaig. NS30u, 262
Whitby, Ontario

“Having a yacht is reason for being more cheerful than most." -Kurt Von.negut

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The Excel advertises its suitability for sailboats FYI.

I installed mine over the winter and it’s amazing. Of course, you must install a propane detector in the bilge and CO detector.

I had a hood made to tie it into the charlie noble rather than venting into the cabin. FWIW, the Excel fits perfectly in the spot of my old Rinnai. Same bottom bolts, same piping connections, same locations. It heats up and delivers hot water in less than 10 seconds.

Thanks,

Bob Gehrman
NS30U #396 “Quickbeam”
Baltimore, Maryland

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Just one comment about adding 110V to a boat. I thought all of our boats, at least from the 26 up, come with that standard. Also, when I went to the engine heated water, I gained storage space and another vent. BTW, I’ve never had to come back out of the shower and turn on the hot water that I’ve forgotten. (Photos available)

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

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BTW, I’ve never had to come back out of the shower and turn on the hot water that I’ve forgotten. (Photos available)

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

Hi Joe,

For a moment I was wondering if I had jumped into another forum, like Cruising Anarchy!!!

Peter Moodie
Nonsuch 30U Catalyst #366

Sidney, BC/Winnipeg, MB