[Rolf]

Planing my cabinet framing layout and need to figure out forsure where to mount
my propex 2800 , It needs to go on driver side and I really would like to place it
fwd of wheel well, this may not be the best spot as far as routing for the exhaust
goes , the exhaust would need to have a 90 degree bend at the end as not to have
wind pressure directly blowing to exhaust while driving , I don’t plan on using heater
while driving … check out the picture drawing, is this ok ? Is a 90 degree bend at
end of exhaust going to mess with the heater operation , I think I recall reading
about, but I am not really clear on this?
cant run the exhaust to rear and have vent out more to the open because the wheel
well is in the way?

 

[Boondox]

Looks OK to me. I put mine behind the wheel well on the driver's side and it does more twists than your diagram shows and works fine. I aimed my towards the back not because I want to use while driving but to minimize crap flying in there when driving.

 

[Rolf]

Yaa I am thinking maybe a little more than a 90 to aim out of the road wind more?

 

[Vanaroo]

Deleted because I couldn't find documentation of what I wrote (maybe I was thinking of another heater).

 

[Michael Ophus]

I cut a three inch hole in the roof with a holesaw, My propane heater has a chimney. It is designed well, No rain water runs down the chimney in 80 mph winds.
In the early years of the forum no one could agree on what was the best choice of heater and many people were just buying Mister Buddy heaters instead, I decided to try a boat heater

 

[andyl]

I routed my diesel heater exhaust down and out the side. No low spots for water to collect. So far it hasn't been torn off by deep snow or rock strikes.

Our intake is a few inches long - not sure what the purpose of a long intake line.

We also never use the heater while moving.

 

[Mc2guy]

I routed my diesel heater exhaust down and out the side. No low spots for water to collect. So far it hasn't been torn off by deep snow or rock strikes.

View attachment 182526

Our intake is a few inches long - not sure what the purpose of a long intake line.

View attachment 182527

We also never use the heater while moving.

You may never have a problem, but the reason for the longer intake is threefold. First, to distance the intake from the exhaust and ensure you are getting sufficient O2 into the combustion chamber to avoid a rich or incomplete burn and carbon build up. Second, to dampen noise of the intake fan, which with a short run will be significantly louder. Lastly, the induction fan on the combustion chamber is tuned to a certain airflow, to match fuel rates for complete combustion. If the intake side is shorter, the vacuum pressure created by the induction fan will be lower creating a higher airflow to the combustion chamber, potentially delivering more O2 than the fuel pump is designed to delivery and a resulting lean burn. Probably not going to be an issue for you in a low pressure combustion system like a bunk heater, but those are the reasons for the longer intake tubing.

 

[Vanaroo]

Lastly, the induction fan on the combustion chamber is tuned to a certain airflow, to match fuel rates for complete combustion. If the intake side is shorter...... potentially delivering more O2 than the fuel pump is designed to delivery and a resulting lean burn.

To elaborate on the point @Mc2guy brought up above about the intake length (caveat: @Mc2guy clearly understands it better than I do so if anything I say below contradicts what he said go with what he said), when I spoke with the folks at Sure Marine about the Propex in general, they said (If I understood this correctly) the Propex is made to run on about 13" of water column (13" wc) because the standard is different in the UK. Here (US and I think Canada too) we typically run our propane regulators at 11" wc because that's what our appliances generally expect. (Propane under less pressure to flow.)

Hence, right out of the gate, the Propex is already trying to run on a mixture of less fuel/more air than designed for when dropped into our 11" wc systems. Sensors apparently don't like that and faults happen (and then people call Sure Marine if they bought it there). With the full recommended length of the intake, the extra air restriction helps balance this out a bit (essentially less air is delivered to the unit than if the hose was shorter, thus balancing out the 11" wc propane delivery better).

 

[kenryan]

I've been wondering if I can adjust my two stage regulator so that it is closer to the British standard? Or perhaps I could get my propane shop to adjust it?

 

[SLOFO]

Probably spoke with the same person at Sure Marine as I remember the WC aspect as well. He also said in UK at least- perhaps on the Continent as well they use butane which burns different from propane.

 

[Boondox]

I've been wondering if I can adjust my two stage regulator so that it is closer to the British standard? Or perhaps I could get my propane shop to adjust it?

I suppose as long as you are running only the heater you could get an adjustable regulator and measure the pressure to find the right set point.

However, mine seems to run fine and make plenty of heat. I'd just make sure that you use appropriate sized plumbing on the supply side so it doesn't further choke the pressure/volume and call it good. At least, that is what I did.

 

[kenryan]

I suppose as long as you are running only the heater you could get an adjustable regulator and measure the pressure to find the right set point.

However, mine seems to run fine and make plenty of heat. I'd just make sure that you use appropriate sized plumbing on the supply side so it doesn't further choke the pressure/volume and call it good. At least, that is what I did.

I'm perfectly willing to take that approach, but if it is a simple matter to correct the pressure so that it is closer to what the heater has been designed and tested on, for me that would be a no-brainer.

My equipment consists of 2 X 30 pound propane bottles (aluminum), each with its own regulator, the Propex 2800 and a 2 burner Dickinson cooktop. One bottle/regulator feeds the Propex, the other feeds the Dickinson. The Dickinson calls for 11" wc and the Propex calls for "propane gas 37 mbar ... the 2800 can also be used on 30 mbar propane but the heat output will be reduced."

The manual does not say how much the output is reduced, but 37 mbar is 14.8 inches wc which is an increase of more than 30% over 11 inches wc, so the output reduction could definitely be meaningful. It also occurs to me now that I could probably find a regulator for sale that is sold as a 37 mbar regulator.

 

[Boondox]

I'm perfectly willing to take that approach, but if it is a simple matter to correct the pressure so that it is closer to what the heater has been designed and tested on, for me that would be a no-brainer.

My equipment consists of 2 X 30 pound propane bottles (aluminum), each with its own regulator, the Propex 2800 and a 2 burner Dickinson cooktop. One bottle/regulator feeds the Propex, the other feeds the Dickinson. The Dickinson calls for 11" wc and the Propex calls for "propane gas 37 mbar ... the 2800 can also be used on 30 mbar propane but the heat output will be reduced."

The manual does not say how much the output is reduced, but 37 mbar is 14.8 inches wc which is an increase of more than 30% over 11 inches wc, so the output reduction could definitely be meaningful. It also occurs to me now that I could probably find a regulator for sale that is sold as a 37 mbar regulator.

Let us know what you find. I am curious. Pity it is fairly difficult to do accurate BTU measurements to determine how much difference it makes. I can say that in an uninsulated van with an outside temperature in the low 20's F the Propex HS2800 running on 11"WC didn't have a problem keeping the van warm. Did run quite a bit of course. In my case I have a single tank so I am pretty much stuck with how it is. Which luckily doesn't seem to be a problem.

 

[Vanaroo]

Just as a note (I have not as of yet bought a Propex so it's only talk at this point), Sure Marine did suggest turning up the regulator a bit as one option. I have other appliances on the same regulator and wasn't sure how that might affect them so wasn't overly keen.

Another option would have been to run a second regulator (for example, boats have one regulator per appliance when using propane).

However, as mentioned above by @Boondox (and also by Sure Marine) the Propex seems to work well on 11" of wc as long as the intake hose is not too short.

One other thing they mentioned in relation to this is that the btu the furnace puts out on our system is going to be slightly less than advertised (for same reason of less fuel, IIUC). They couldn't quantify it precisely -- and it wasn't a huge amount -- but the topic came up because I was debating between the two sizes of Propex (for just under 550 cubic feet of space, sparingly insulated, moderate climate usage).

 

[kenryan]

Let us know what you find. I am curious. Pity it is fairly difficult to do accurate BTU measurements to determine how much difference it makes. I can say that in an uninsulated van with an outside temperature in the low 20's F the Propex HS2800 running on 11"WC didn't have a problem keeping the van warm. Did run quite a bit of course. In my case I have a single tank so I am pretty much stuck with how it is. Which luckily doesn't seem to be a problem.

If I didn't live in Alaska, I would just let this go. But I want all the heat I can get out of that Propex, and I have a feeling that the output difference could be significant with an increase in pressure. But the Dickinson manual is pretty adamant about the 11" w/c propane requirement. That prompted me to contact Dickinson with the following question:

"I have one of your 2 burner drop in cooktops. The manual clearly states to use 11 inches w/c propane pressure. I also have a Propex heater that prefers 37 mbar propane pressure (14.8 inches w/c). I would like to adjust my 11 inch w/c regulator to the midpoint between the two appliances (12.9 inches w/c)."

Here is their response:

"That will work just fine as that pressure will not cause any damage or operational issues with our appliance."

So my approach will be to attempt to adjust my 11" w/c regulator to 13" w/c output, when I get to the final installation.

 

[Boondox]

If I didn't live in Alaska, I would just let this go. But I want all the heat I can get out of that Propex, and I have a feeling that the output difference could be significant with an increase in pressure. But the Dickinson manual is pretty adamant about the 11" w/c propane requirement. That prompted me to contact Dickinson with the following question:

"I have one of your 2 burner drop in cooktops. The manual clearly states to use 11 inches w/c propane pressure. I also have a Propex heater that prefers 37 mbar propane pressure (14.8 inches w/c). I would like to adjust my 11 inch w/c regulator to the midpoint between the two appliances (12.9 inches w/c)."

Here is their response:

"That will work just fine as that pressure will not cause any damage or operational issues with our appliance."

So my approach will be to attempt to adjust my 11" w/c regulator to 13" w/c output, when I get to the final installation.

Yup, if I lived in Alaska I would be interested in squeezing out every BTU too! You know, since a stove is my only other appliance and I am sure it wouldn't mind the extra pressure I will fool with an adjustable regulator I have. Although I think the one I have may have pretty coarse adjustment. Have you sourced an adjustable regulator yet? Or perhaps one just built for 37mBar?

 

[kenryan]

Yup, if I lived in Alaska I would be interested in squeezing out every BTU too! You know, since a stove is my only other appliance and I am sure it wouldn't mind the extra pressure I will fool with an adjustable regulator I have. Although I think the one I have may have pretty coarse adjustment. Have you sourced an adjustable regulator yet? Or perhaps one just built for 37mBar?

I think almost all regulators are somewhat adjustable. I don't plan on getting a different regulator. Instead I will see if I can adjust my 11" regulator to 13". If I fail, my next step will be to use the system at 11" and after that determine if I want to change regulators. My propane locker is a tight fit, and swapping regulators would probably also mean some new hoses.

 

[Vanaroo]

Just as a note: I have never messed with this but I think I remember my "RV" stove having it's own little regulator (?) under the top? As in, it was in with the burner tubes and stuff where you would clean after lifting the top up. I don't have the range here to look at but remember it as a smallish/brass square thingie. This would have been downstream of the system regulator at the tank.

Edited to add: I'm not sure why I think it was a sub-regulator, but for some reason that sticks in my mind. But so don't take it as certain truth.

BTW, I remembered 13" wc for the Propex but obviously it was even more than that.

 

[Boondox]

I think almost all regulators are somewhat adjustable. I don't plan on getting a different regulator. Instead I will see if I can adjust my 11" regulator to 13". If I fail, my next step will be to use the system at 11" and after that determine if I want to change regulators. My propane locker is a tight fit, and swapping regulators would probably also mean some new hoses.
View attachment 182632
View attachment 182631

Nice propane locker.

The one and only regulator I took apart was not adjustable. I was building a forge burner. That is when I got the adjustable one I have around here somewhere. Please let me know what you find inside, pics would be awesome. I also have another standard-ish regulator kicking around, maybe I'll crack that one open and see if is can be adjusted.

 

[Vanaroo]

@kenryan
That is a really nice looking propane locker. Without the tanks in it it has a groovy art piece vibe looking at the layers I have a question though: Seeing how relatively tightly the tanks fit into their spots, do you have a ventilation hole (leading outside) above the top "shelf" in case there is a leak in your regulator or connections? Or maybe it's not necessary..... I'm only getting the photo view so I might not be seeing it how it really is.