Propane demand hot water heaters?

[rwthomas1]

Hello All,
There are a few Niagaras and a Nonsuch at my yacht club that have "Paloma" brand demand hot water heaters fired by propane. They were installed by the factory. If you haven't seen one of these units they are pretty nifty. They mount on a vertical surface and heat water directly as it is used. Exhaust is vented through a charlie noble in the deck just like a propane salon heater. The Paloma equiped boats all have propane fired salon heaters as well that utilize the same exhaust flue.

You should see where I am going with this as the benefit is heating for comfort, heating for water using the same fuel and sharing an exhaust flue. From a strictly space-saving issue the Paloma heater mounts on the bulkhead in the head and space is gained by removing the existing electric/coolant operated storage type water heater in the engine space.

On an older E38 like mine the Paloma would easily mount on the bulkhead and a salon heater like a Force 10, etc. could mount on the salon side of the same bulkhead making sharing of the exhaust flue.

The drawbacks AFAIK are the Paloma's are not supposed to be used on boats.... Never mind that Niagaras and others have had them installed at the factory and my limited research has not turned up any issues. Anyone have any input on these types of heaters? The added benefit is converting to propane would utilize the built-in lockers on the E38 and allow the same fuel for cooking, heating and heating water. Also since we intend to cruise propane is easier to find.

Sound like a good idea?

RT

 

[Guy Stevens]

I have had one on my last three boats.

They are great, only brand to have is a Paloma though. They are the only one with the burner designed correctly. The rest produce CO. Note that I have tested all three of mine with some very sensitive CO monitoring gear from the HVAC profession, none have produced any.
I have installed them on a number of other boats too. Never a problem.
Don't tell them that you are going to put it on a boat when you order it they won't sell to you.
Guy

 

[Loren Beach]

Caution is a good thing...

And if you come across a used "Hot Wolter" unit at a swap meet, pass on it.
You might want to run this whole idea by your insurer first, also.

Loren

 

[Sean Engle]

Not that I'm advocating this type of use - but I thought that these types of units were supposed to have those intake/exhaust pipes that also drew in the air they combust (making the combustion air a non-issue - assuming no leaks, of course).

I know I'll be replacing our home waterheater with this type of unit once our existing one dies. I'm not sure about doing on a boat, however...

//sse

 

[rwthomas1]

Great to hear this is the good idea I think it is. Hot water is only one part of the equation. I am thinking cabin heat too so the only other option is a combo system from Espar, Webasto, ITR, etc. that provide heat and hot water. They are double the price of a Paloma and wall mounted propane cabin heater though.

The only other question is which Paloma? I am thinking this one. http://www.plumbingsupply.com/palomaflashwaterheaters.html#specs
It appears to be the smallest they make? Thanks, RT

 

[Joe]

If you're looking at that unit, you may want to check these prices:
http://www.hot-water-heaters.com/tanklessprice.htm
(found via google: no affiliation)

 

[Guy Stevens]

the PH6 is definately the unit that you want

You really want a PH5 but they don't make them anymore. The PH6 will do you great.

The Webasto hydronic unit is great, if a pricey way to go. We just finished installing two of them here for clients. They work great, and both have evenly toasty boats, and as much hot water as they can use at any time. (The Everhot is a great on demand heat exchanger for hydronic units). However they are PRICEY and take a lot of effort to install. Generally for a good install you can count on about 100 man hours for a 40 foot boat.

You might want to rethink the propane cabin heater. They produce LOTS AND LOTS of water vapor. Ends up being a lot like a steam room inside the boat.

Guy

 

[footrope]

Water vapor!

You might want to rethink the propane cabin heater. They produce LOTS AND LOTS of water vapor. Ends up being a lot like a steam room inside the boat.

Good point about propane and water vapor, Guy.

The water vapor potential of propane was a factor in my decision to go with a diesel hydronic in my E38. A factor against a bulkhead radiant type was that there isn't a good place to install a bulkhead heater in my cabin - not a problem for every boat. So once we decided on the hydronic, we decided to add a v-tube heat exchanger (coolant to water) to have instant hot water. It takes about 15 minutes to heat the coolant circuit for hot water in our system. If you're running the heater to warm the cabin anyway, instant hot water is there no matter what the regular water heater status is. It works great, by the way, both for showers and doing dishes. Really, we could probably go without a tank-type water heater if we wanted to.

We fight condensation all the time up here in the NW because our boats usually sit in the water year-round, and we hover in the 30s and 40s all fall, winter and spring. Add two people sleeping in the cabin and we get condensation anyway, since the heater is off overnight.

After all that, I haven't used propane bulkhead heaters ever. The diesel hydronic cost me around $8K, professionally installed.

 

[Loren Beach]

Vapor?

I thought that all the hydronic heaters (and the forced air furnace ones) were stack-vented (and force vented) to the outside of the boat, regardless of fuel used.

Whether you go with diesel or propane, ALL the exhaust is external.
Heck, even the Force 10 "Cozy Cabin Heater" on our prior 26 boat was externally vented via a SS stack. It was propane. Heat was always dry and hot. We did have to add a fan by the stack, near the overhead, to circulate the warmth around the cabin.

Now, if you have an open flame device inside the boat, like a propane or alcohol cookstove, that will indeed put a lot of vapor into the interior.
For instance our Origo stove does add noticeable amounts of water vapor when cooking.

We just wish we had a "spare" bulkhead on which to install a modern stove in our model of boat... But, we do not, and so a diesel furnace in somewhere in the future, finances allowing.

Loren

 

[roger hinds]

Rob, by looking at the specs and picture, the Poloma PH6 appears to be a conventional flue type water heater, with a 4 in. vent If this is the case, it would be drawing air from inside space, venting through the roof. This is not the type of water heater you would use for small or tight construction situations, like a boat, or mobile home. The potential for dangerous reduced oxygen levels or CO poisoning would always be present. In most gas fired applications, using direct vented equipment, with a sealed combustion chamber, is a superior alternative.
Roger

 

[soup1438]

Propane's other problems...

One question I have-- and, yeah, being on Florida doesn't make heating something high on the agenda, though cooling, on the other hand... -- is about the fact that PROPANE units are under discussion.

Color me paranoid. On my job (Systems & Network Administration) my paranoia goes up to (at least) eleven, kind of like the amplifiers that Spinal Tap used.

Not only don't you want to draw air from the cabin to feed the flame (or however this is done, like the catalytic heaters) but you also want to make sure that any leakage of propane isn't going to seek the bilges, so sniffers and fail-safe mechanisms are called for, aren't they? Considering the level of paranoia needed for stoves/ovens, I'd be *real* anxious about such a demand heater.

And, yeah, I don't like the idea of a cold shower, either, so, if I had a big enough boat to set up a shower, yes, I would want a GOOD heater, and a demand heater sounds like heaven.

But, again, maybe I fear propane leaks too much? Am I too paranoid?

 

[rwthomas1]

While I understand the potential for problems with propane they can be mitigated. Obviously any propane system would have to be installed with lots of forethought and care, utilizing sniffer sensors and such. The main advantage to propane is availability. I currently have CNG for cooking. On a long cruise outside the US refilling CNG bottles is next to impossible. Converting to propane for cooking alone makes sense.

Regarding the issue of a Paloma water heater many have used them without issue. Manufacturers have installed them from the factory. IMHO, the matter is simply commonsense. Running a unit like that in a confined space is not a smart thing. Obviously keeping the head door open and some ventilation while the heater is in operation would make sense. Again, operator error can lead to problems like anything else.

My only issue with the Paloma type heaters is legality. I have yet to find an insurance company that will cover a boat with a heater like this. My inquiries have been limited but they don't seem to like them. The difference seems to be if it was factory installed or not. Hmmm, will have to look into this some more.

RT

 

[mark reed]

There was a Paloma water heater installed in our boat when we bought it. The surveyor went ballistic and insisted that it be removed, and of course the insurance company went along with him. Ours was installed along a purpose-built bulhead at the forward end of the starboard cockpit locker, and the exhaust hose vented through the transom (it was well insulated where it was routed aft). The FO had used it without any problems for 5 years, and swore it was the only thing that could induce his teenage daughter to go cruising with mom and dad!