Do you HAVE to vent it? Tankless Water Heater

[buslifeyo]

To keep it to the point:

We bought a Meray 10L tankless (propane) for our 33' Bluebird (has a 12v fan in the bathroom and 2 emergency hatches, one hatch has a fan for additional venting) Manufactures specs say to vent to the outside with a 6' vertical pipe.

My question:

Has anyone using, specifically, the Marey 10L skipped this step? What was your result? Did you die? (I hope not)

Disclaimer:

I know specs were created to keep consumers safe. I understand the danger of co2 build up in a sealed box. I do not wish to build something unsafe. I am asking because I've seen strong opinions about tankless water heaters and other larger propane appliances (ie stove or heater) on here for both sides (to vent or not to vent). I've gone crossed eyed reading through the water heater discussions, but did not see this question about this particular model. It seems that others have skipped the venting on smaller units like the ecotemp with out issue (much to the disgust of other builders on this forum).

Thank you for reading

[BarnYardCamp]

I'd say absolutely vent it. It was designed to be used in a house, which means substantially more square feet of air to dilute exhaust gasses. So, even if you have a large bus, it's still a tiny metal tube, relatively speaking.
The manufacturer says vent it. You should!
I'd be skeptical of running even a "vent less" propane appliance in a space as small as a bus.
I see you mentioned some exhaust fans...I wouldn't want to rely on that, I may be wrong, but I believe that CO2 is heavy, and will build up from the floor. Venting from above may not be good enough. Don't take shortcuts w/ safety.
Good luck to you.

On my bus, I'll be using an electric water heater..if we boondock sometime, then we'll make do with cold water.

[peakbus]

Vent it! I am a home inspector. CO is colorless and odorless. You don't know its there. There are "vent free" heating appliances but they all have big warnings about airflow, opening windows, proper combustion. Why risk it.

[buslifeyo]

Thank you! Every opinion is helpful. We thought about going with 110 heater ourselves but plan on long term boondocking/ dry camping. I don't want to suffocate just to save power though. I know of some vanlifers who skip venting and just use windows and doors for airflow but that is a much smaller tube with better airflow when its opened up.

[A_Bus_Called_Quest]

I would join the choir of "Vent it!"

We have a gasland tankless heater, I vented out the top but there are a ton of air inlet vents in the body of the unit.

Just to be sure I'm putting a battery powered CO and Propane alarm in the cabinet with the heater. Same for our oven, alarm in the cabinet just to be safe. $50 now or dead later ;)

[Wicked Mickey]

Perhaps the thought 2 C3H8 + 9 O2 → 4 CO2 + 2 CO + 8 H2O + Heat may enter into your decision making. If you take the CO alarm approach you will still have a good bit of water vapor. -perhaps of importance if it is in a cabinet.

[Rwnielsen]

I'd be hesitant to use any propane without some ventilation, cooking, heating, etc...

[A_Bus_Called_Quest]

Originally Posted by Wicked Mickey

Perhaps the thought 2 C3H8 + 9 O2 → 4 CO2 + 2 CO + 8 H2O + Heat may enter into your decision making. If you take the CO alarm approach you will still have a good bit of water vapor. -perhaps of importance if it is in a cabinet.

Haha I understood about half of that - but good call on the water vapor in the cabinet from the propane burning.
In our case, the heater is located under our sink, not super air tight and the heater only kicks on when we turn on the hot water so I'm not TOO worried about it.
But now that you mention it, I'm definitely going to keep an eye on it. Thank you!

[buslifeyo]

Originally Posted by Wicked Mickey

Perhaps the thought 2 C3H8 + 9 O2 → 4 CO2 + 2 CO + 8 H2O + Heat may enter into your decision making. If you take the CO alarm approach you will still have a good bit of water vapor. -perhaps of importance if it is in a cabinet.

What does your equation mean? It seems like an important part of decision making that I am completely unaware of. We do plan on having a smoke and CO detectors. The heater will be in an open area not a cabinet.

[buslifeyo]

Bear Gerschafer


You understood about twice as much as me! Do you have an LP tankless water heater? How did you vent it? If at all?

[A_Bus_Called_Quest]

We do have a LP heater water heater and oven/range.
We haven't used it full time yet but I've have pretty good experiences with similar water heaters in outdoor applications.... hot water when you need it!

I know propane burns "wet" for lack of a more scientific term... it produces condensation when burned. That's why people opt for diesel heaterss, wood stoves, or glycol for heat over propane.

For cooking and water, we went with propane because electric powered heat is pretty inefficient and we didn't want to ramp up our solar and batteries just for water and a stove when propane is around and has been used for years and is available everywhere.

[musigenesis]

Originally Posted by buslifeyo

What does your equation mean? It seems like an important part of decision making that I am completely unaware of. We do plan on having a smoke and CO detectors. The heater will be in an open area not a cabinet.

It just means that when you burn propane, it produces carbon dioxide, carbon monoxide and water. Which is why the Mr. Buddy propane heater would be named Mr. Soggy Death if there were any truth-in-product-naming laws.

You should definitely vent this thing.

[cadillackid]

Vent it.. here is why..



1. appliances that are designed to be non vented are tested for the amount of CO they output while ooperating.. typically they are required toi have a very clean and complete burn, *OR* they are designed to be used for a short poeriod of time. *OR* they are very small BTU so it is expectedt that the CO will disperse into the space they are DSIGNED for.



2. Tankless water heaters work because they have a very Large burner and can flash-heat the water as it travels through the machine. this means that while your water is on he unit is emitting LARGE amounts oif exhaust.. sinmce the unit is Designed to be vented, the CO emission requirement of it isnt as stringent as an appliance that is being rated for unvented use.. what this means is that not only are you emitting more exhaust for the time it is on, but potentially a higher concentration of CO..



3. you normally expect your tankless heater to be on for a short period of time, however what if someone turned on the sink and left it on.. or you spent alot of time working outside and got ver ydirty so now you want to take a longer shower, or it takes longer to wash up so you run the heater longer..


if you are looking for the most efficiency or the easiest venting then buy a condensing Tankless heater where you can do a small sidewall vent that dioesnt need a vertical rise and very little heat is lost..



the tankless in my house uses 2 PVC pipes as vents and is standard schedule 40 pipe.. no worries around other combustibles, etc.. it is 2 pipe so it uses outside air for combustion air.. unit does its jiob well.

[Doktari]

I would vent it if it was my bus. Exhaust the CO gas and water vapor outside. I’m wondering if any tankless on-demand water heaters are designed for pre-heated water from solar in a electric hot water tank? The reading I did years ago mentioned only one model by Bosch that was rated to take preheated water. Ive heard with some others the water comes out scalding hot. Is it a “modulating” heater that can adjust to incoming water temperature?

[Ronnie]

I have the same one and do not have a vent directly on it. Although I do have a vent in the bathroom where it is and will usually have the vent open to let out shower moisture. So in effect it does get vented.

[Rock-N-Ruth]

Originally Posted by buslifeyo

To keep it to the point:

We bought a Meray 10L tankless (propane) for our 33' Bluebird (has a 12v fan in the bathroom and 2 emergency hatches, one hatch has a fan for additional venting) Manufactures specs say to vent to the outside with a 6' vertical pipe.

My question:

Has anyone using, specifically, the Marey 10L skipped this step? What was your result? Did you die? (I hope not)

Disclaimer:

I know specs were created to keep consumers safe. I understand the danger of co2 build up in a sealed box. I do not wish to build something unsafe. I am asking because I've seen strong opinions about tankless water heaters and other larger propane appliances (ie stove or heater) on here for both sides (to vent or not to vent). I've gone crossed eyed reading through the water heater discussions, but did not see this question about this particular model. It seems that others have skipped the venting on smaller units like the ecotemp with out issue (much to the disgust of other builders on this forum).

Thank you for reading

We have ours hanging on the side of a cabinet near the emergency door. When Ruth is doing dishes, or we are drawing more than 15 or 20 seconds of hot water, we open the roof vents and the "grocery" door.

For carbon dioxide and moisture produced by this very quick water heater this is a suboptimal solution solution. Not completely safe. As others have mentioned the water heater works so well because of it's big flame.

We are building a second bus after a two year prototype run in this bus. The new bus will use the same water heater, vented out the side of the bus.

I would be concerned with not only the C02, and moisture, running it under a counter, but the immense amount of trapped heat.


Not good for your cabinet or the contents, and perhaps a fire Hazzard.

Be safe. Rock-'n'-Ruth.

[Rwnielsen]

Originally Posted by Doktari

I would vent it if it was my bus. Exhaust the CO gas and water vapor outside. I’m wondering if any tankless on-demand water heaters are designed for pre-heated water from solar in a electric hot water tank? The reading I did years ago mentioned only one model by Bosch that was rated to take preheated water. Ive heard with some others the water comes out scalding hot. Is it a “modulating” heater that can adjust to incoming water temperature?

I've read that most are rated on temperature rise at a given flow rate. So, the warmer it is going in the hotter it is coming out.
This is second hand knowledge and may not be true.

[Ronnie]

Originally Posted by Rwnielsen

I've read that most are rated on temperature rise at a given flow rate. So, the warmer it is going in the hotter it is coming out.
This is second hand knowledge and may not be true.

From first hand knowledge yes this is true.

[milkmania]

Although I cannot comment on venting...

I can comment regarding heating hot water, as I use a propane on-demand for my hillbilly hot tub��

I circulate heated water from bottom of tub, through a pump & filter, heater, and back into top of tub.
The heating circuit is separate from the filter circuit.
Parts list is in the comments.


Video starts out slow... but, it’ll get you there!
Hillbilly Hot Tub

please forgive me for threadjacking

[LargeMargeInBaja]

Let's extrapolate:
.
Would I operate a lawn-mower inside my rig... without ventilation?
Would I operate a kerosene heater inside my rig... without ventilation?
In the cinematic version of ON THE BEACH, the Fred Astaire character loses all hope... and runs his award-winning race-car in his closed garage.
.
Would I operate a gas stove or oven inside my rig... without ventilation?
Those burners exhaust toxic waste into my breathing air.
This's one reason we cook outside.
Avoiding consuming toxic airborne contaminants is also one reason we use electric kitchen 'sous vide' circulation heaters to get our worshing water nice-n-toasty.