Propex Heatsource Furnace Installation Report in FWC Eagle Shell

J

Jeff Riemer

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Feb 3, 2015
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23
Location
Squamish, B.C.

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Very nice install!
I recently received a Propex that I will be installing soon. The instructions which came with the heater state that the full length of the intake and exhaust tubing must be used in order for the heater to work properly. Did you find this to be true? I'm guessing from your pictures that you didn't use the full 750mm of metal tubing. I would love to avoid the convoluted tube path I will have to use if I am to use the full length of tubing.
 
I struggled with that too until I realized the instructions meant that the rigid tubes that are attached to the furnace should not be shortened, these are about 1-3/4" long. The flexible ducting can be shortened. Interestingly, the instructions you download from the Propex website do not even mention the tubes or shortening them or anything, only the paper copies that I got from the dealer mentioned them...
 
Nice install, like the marine vent. ? only 1/4" copper propane line. Just seems small for the low pressure.
 
Thanks for the comments. The 1/4" line is spec'd by the manufacturer. These units are much more efficient and burn less propane than the old style suburban units so they can use a dmaller line.

Jim, the large brown line is the cold air return and it draws from inside the camper behind the furnace for now to separate the warm air outlet until I can build a panel. Combustion air inlet and exhaust are completely separate from the camper air.

Jeff
 
Thanks Jeff. Are there any other penetrations to the camper besides the inlet? I'm also building out a shell and I'm trying to decide between Propex or the standard Atwood furnace. FWC use to offer propex furnace as an option. I'm guess they went away from it due to cost.
 
Hi, new here. I am Karl Mullendore, the US rep and importer for Propex. I like to see that folks don't have any issues with reliability of these heaters, even if they didn't buy through the US delaer network.

Regarding the Propex HS2000 installation manual, it states:

"A 0.75 metre length of 22mm flexible stainless steel tubing with a special
end cap is supplied for ducting the products of combustion away to the
edge of the vehicle. The tubes may not be shortened but can be extended
for certain applications. A 0.75m length of combustion air pipe is provided, which is also fitted with
an end cap. This should be attached to the heater with the hose clip
provided and pointed in the same direction as the flue pipe.
Note: The combustion air pipe can be terminated underneath the vehicle
making sure the end of it is at least 0.5 metres away from the end of the
exhaust and that they are not pointing directly at each other. Take care to
ensure that both pipes have a slight downward slope to prevent any
possibility of water traps. Make sure that neither the flue or the combustion
air inlet pipe are terminated in an under-floor box section."

The reason being that the Omron airflow sensing device senses reverberation in the inlet and burner pipes, and when they are cut shorter than the supplied length the sensor may detect uneven pulses in the burn and shut the unit down. You may get away with it at lower elevations, however at altitude we might hear you cursing the furnace because it will shut down with an airflow fault code. You may of course shorten the heat ducting to any length.

In regards to the Atwood vs Propex: the Atwood efficiency is 75%, resulting in an output of 9000 btu. Propex efficiency ratings are 93%, resulting in 9500 btu for the 2000 and 2211, 9700 btu for the 2800 model. FWC has not approached me for a bulk OEM supply price, they could be using a more compact and efficient furnace otherwise. :)
 
westyventures said:
Hi, new here. I am Karl Mullendore, the US rep and importer for Propex. I like to see that folks don't have any issues with reliability of these heaters, even if they didn't buy through the US delaer network.

Regarding the Propex HS2000 installation manual, it states:

"A 0.75 metre length of 22mm flexible stainless steel tubing with a special
end cap is supplied for ducting the products of combustion away to the
edge of the vehicle. The tubes may not be shortened but can be extended
for certain applications. A 0.75m length of combustion air pipe is provided, which is also fitted with
an end cap. This should be attached to the heater with the hose clip
provided and pointed in the same direction as the flue pipe.
Note: The combustion air pipe can be terminated underneath the vehicle
making sure the end of it is at least 0.5 metres away from the end of the
exhaust and that they are not pointing directly at each other. Take care to
ensure that both pipes have a slight downward slope to prevent any
possibility of water traps. Make sure that neither the flue or the combustion
air inlet pipe are terminated in an under-floor box section."

The reason being that the Omron airflow sensing device senses reverberation in the inlet and burner pipes, and when they are cut shorter than the supplied length the sensor may detect uneven pulses in the burn and shut the unit down. You may get away with it at lower elevations, however at altitude we might hear you cursing the furnace because it will shut down with an airflow fault code. You may of course shorten the heat ducting to any length.

In regards to the Atwood vs Propex: the Atwood efficiency is 75%, resulting in an output of 9000 btu. Propex efficiency ratings are 93%, resulting in 9500 btu for the 2000 and 2211, 9700 btu for the 2800 model. FWC has not approached me for a bulk OEM supply price, they could be using a more compact and efficient furnace otherwise. :)
Click to expand...
Can you talk about the noise level comparisons between atwood and propex. Its not practical for truck campers to terminal underneath the vehicle since that would involve penetrations in the camper and truck bed.
 
Noisewise, it does not seem any quieter than the old suburban unit I had in my previous camper. Just a subjective comparison. Its not loud enough to wake me up and im a light sleeper. Karl, re the combustion air and flue lines. My furnace aeems to run fine with no airflow faults or cutouts, I guess time will tell how it works in all condiTions. I could route the flue in a loop to lengthen it but that is not a very clean approach. I update tgis if I run into any issues.
 
super doody said:
Can you talk about the noise level comparisons between atwood and propex. Its not practical for truck campers to terminal underneath the vehicle since that would involve penetrations in the camper and truck bed.
Click to expand...
The only sound level testing I have done has been on the Propex itself. Measured with a dBa meter at approximately 12", on the bench, the HS2000 shows 63-65 dBa. The HS2211 is a tad quieter at 55-58 dBa.

There is the propex marine hull fitting that will terminate both pipes in a sidewall, we've sold a few of those to truck camper manufacturers, although I like the single port models available from other sources and may soon stock a few of those. One batch of 18 we sold to a truck camper builder in the US for distribution to Iceland just ran the pipes out on a sidewall, less than elegant IMO.
 
Jeff Riemer said:
Noisewise, it does not seem any quieter than the old suburban unit I had in my previous camper. Just a subjective comparison. Its not loud enough to wake me up and im a light sleeper. Karl, re the combustion air and flue lines. My furnace aeems to run fine with no airflow faults or cutouts, I guess time will tell how it works in all condiTions. I could route the flue in a loop to lengthen it but that is not a very clean approach. I update tgis if I run into any issues.
Click to expand...
I think Propex (or the manufacturer) may have relaxed the AF sensing slightly if that's the case. Since I am now at 4500' and have access to 10,000', I will do more testing. In early 2010 production the Omron sensor system would shut down the heater with even a couple inches cut from the inlet pipe. A clean-sounding, rumble-free burn means it will likely be ok.
 
Thanks Karl, The Through hull-marine fitting I used went in perfectly and is the cleanest fitting i could find, although expensive, it is solid Stainless Steel and will never rust on an RV, unlike the Chrome plated ones…I modified the exhaust flue a bit and added a coil loop, same location of the furnace and fitting, it ran perfectly before but this works too, so I am not anticipating any issues just better safe than sorry since I am at sea level in Squamish...
 
The combustion intake air line is routed to the wall inside the bed, this is the plywood wall and draws from the outside air. The propane feed follows a similar path but is tucked in the corner and comes out the back. It is secured with 1/4" Rubber lined Stainless Steel clips. You can see them in the pics on my website.

Thanks Jeff. Are there any other penetrations to the camper besides the inlet? I'm also building out a shell and I'm trying to decide between Propex or the standard Atwood furnace. FWC use to offer propex furnace as an option. I'm guess they went away from it due to cost.
 
I vented the Propex heater through the plywood (with heat shields for the exhaust) and since my Ocelot sits higher than the bed rails, the inlet and exhaust hoses simply are attached to outside of the camper at opposite ends. I used another heat shield (stock aluminum) to protect the plywood on the exhaust flex tube as well. The Propex furnace is very quiet, our Atwood propane stove makes more noise than the furnace. But, we never have the furnace on all night - we prefer to sleep without extra heat. So far, so good!
 
I've got one in my boat and love it. Doesn't draw many amps either (2.1 if I remember right). I'd like one in my camper or hope that one day this could be an option in a FWC since I'm considering an upgrade in the future.
 
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