Propane Filter Question

[CUCWV]

LPG inline filter?

In my old RV I installed a new Olympian Catalytic heater and connected it to the main LPG tubing. After a month it set off the carbon monoxide detector. I sent it back to Cameo. The manager fixed it free but said that was the last time. He was very nice about it but said it was poisoned due to bad LPG and that I needed to put a filter on it. Camco doesn’t make one or anyone else except MR HEATER. Theirs are for the small disposable tanks. What I found on the net are huge; for large commercial operations. I have a different RV now and I am currently looking for fittings to adapt the MR HEATER filter inline. Is there something else on the market? Was what happened to me before just a fluke or should I concern myself with a possible reoccurrence? Thanks CUCWV

[AFChap]

Welcome to the forum!!

I have not heard of an inline LPG filter. ...not sure of the dynamics of running a catalytic heater, but perhaps running it with a vent open might prevent the CO alarm. I have to assume that meant it was burning oxygen and putting out CO, making the air inside the RV risky for human life. When we feel we need to use something other than our heat pump or LP furnaces, we use a small ceramic space heater in our motorhome.

[RVhauler]

Must say that have never heard of an LPG filter (tho lots of stuff never heard or seen). The only "bad" LPG that I have ever seen was contaimated with moisture or oil and purging tank will resolve that, MY LPG genny has a drain port for oil on it's regulator (not LPG tank regulator which must be drained yearly. (never found anything to drain)

[davecampbell]

Small LP filters are available, I bought one at an auto parts store. Fit into a 1/2" line, its a sintered brass filter element.

Maybe something like this:

CENTURY PROPANE LP BULKHEAD FUEL FILTER MODEL 156 711-2 - eBay (item 260210568697 end time Dec-25-10 10:24:43 PST)

BEWARE using a catalytic heater in a confined space without enough make up air. Propane generates a HUGE amount of CO. I assume a catalyst needs excess oxygen to convert CO to CO2.

Id put a separate CO detector right under the heater.

Yes, its a much more efficient way to heat, but Ive almost died from using an inproper heater in a closed space. A couple stupid motorcross racers (I was one of them) used a white gas heater in a van. We nearly didnt live to tell about it.

[ArmyEOD]

The in line filter will not prevent the heater from producing carbon monxide. Please besafe my friend open a window or run a small ventilator fan. If not be sure that you always have a fresh battery in your detector so you can get out.

[CUCWV]

Dave… Thanks for the reply…. That sounds good as I could not find one. Since I first posted about this what I have done is utilize a “MR Heater” filter. I tapped into the LPG line for the stove top. I got a welding supply company to order the fittings to adapt the filter inline to the quick disconnect valve mounted on the counter side board. They made up the hoses in their shop.

Everyone is concerned about using these types of heaters and I appreciate the input. You can never be too safe. When we are boondocking it is the way to heat with out running your batteries down. I have 3 CO detectors mounted in the coach and always have proper ventilation.

I do feel like the Lone Ranger putting a LPG filter inline as most have not heard of doing so. My concern was in ruining another heater due to contaminate in the fuel. Their term was poisoning the heater. Thanks…. Hal

[Larry & Rita]

If you still have the Mr. Heater box, it states on the direrctions that you need only open the window or a vent about a 1/4 to 1/2 inch. Before I bought it everyone said "open a window" I thought they meant all the way.
I open a window, 1/4 inch, in the bedroom anyway because I like the smell of night air.
I have one of the big Mr. Heaters (two small 1lb tanks) I leave it in the middle of the coach because the glow from the elements is like day time, but it will run you out.

[davecampbell]

The filter may prevent CO formation. Just not directly, the circumstances prove something related to cleaning the heater is causing it.

CO is formed from a too-lean propane mixture (too much air or not enough fuel). Its chemistry, the propane molecule is C3H8 and oxygen is O2 (oxygen cannot remain as a single atom, it comes in twos). Actually to look at it another way, its a too rich mixture that prevents it.

When C3 meets excess O2, the inevitable result is CO2 and excess CO. A C is happy with two O's but another C finds an O and theres a deadly gas. The uneven number of carbons dictate it.

Its not a direct cause and effect, its indirect. A clogged filter or line will reduce propane flow and cause excess CO.

The larger problem is the contaminated propane supply. Find out why theres junk or moisture getting in the heater in the first place (there was/is, else a repair shop would not have found any debris to clean out). May be time to replace the tank AND find another supplier. May be a dirty storage tank, or one with moisture in it. Moisture has to come from the bulk tank, it cant magically soak in through the walls of your LP tank..

As I recall, ASHRAE requires two or three air interchanges an hour (someone with an ASHRAE book check on that) for a house. Granted this is not a house, but air interchange is important anyway, even without a propane burner, humans generate a lot of CO2 by breathing. I had a friend who bought a condo that was so air tight that the NG stove pilot wouldnt stay lit due to lack of fresh air. They had to cut a 3 inch make up air hole in the wall.

So to stop global warming, we have to ban humans???

[hang on, Im calculating the reaction, it may be slightly too rich that causes excess CO]]

CO is produced at 1:4 propane and oxygen or a lower ratio if theres excess CO2 nearby (see attachment)

At 1:5, there is excess oxygen that may break react with stray CO2 (CO2 has heating value, makes 2 CO) and if so, twice the CO is produced for just a tiny increase in oxygen, that is, or a slight loss of fuel flow (as in a restricted burner or PART of a burner being restricted)

The low propane flow both makes the mixture lean, and might cause part of the burner to burn without making CO (slightly rich, soot in the exhaust) and part producing CO.

Makes another case for ventilating human produced CO2!

Any chemists that wander by might check that...

So, yes, its possible for a propane restriction to cause excess CO, or put another way, a lean propane /air mixture (leaner than a rich one that produces some soot, which is largely carbon)

[davecampbell]

Quote:

Originally Posted by larrygrandpa If you still have the Mr. Heater box, it states on the direrctions that you need only open the window or a vent about a 1/4 to 1/2 inch. Before I bought it everyone said "open a window" I thought they meant all the way..

Carbon monoxide goes to the floor (heavier than air) how does it get out the window?

Thought question for the day. The stuff has to have somewhere to go, not just to add more air!

Air exchange is the key.

[a k]

Do yourself a favor and ditch the heaters before you don't wake up dead.

[Gary RVRoamer]

Actually, CO has a molecular weight of 28, which is just about the same as the average molecular weight for air. The oxygen (O2) in air is slightly heavier than CO, but the nitrogen, which typically appears in pairs of atoms, also has a weight of 28. Co mixed quite nicely with air and does not fall to the floor. For that reason, CO detectors are normally located at head height.

[Ray,IN]

CUCWV, The only gas heater I am aware of that is fully approved for indoor use is the smallest Mr. Heater model, all others say they must have some outside ventilation.
Dave has just explained something quite technical- in terms even I understand. Thanks Dave! Gary is right about CO not heavier than air.