Poll, Propex function at 10,000 feet

[Jon_slider]

I have had a Propex for almost 2 years. It lives in a Van located at 7000 feet that is used to drive to Ski Santa Fe, whose parking lot is at 10,000 feet.

The heater is unreliable, despite numerous attempts to solve the problem.

At this point I am resigned to the apparent fact that it simply does not like altitude.

This past weekend at Wolf Creek Ski Area, also with a 10,000 ft parking lot, the unit failed to light at all, despite over half a dozen attempts. Very dissapointing.

Before I send it in for service again, I want to know if my problem is "normal".

Does anyone here have experience using their Propex successfuly and reliably at 10,000 feet?

I usually have to try over and over and over again to get it to light. I have increased my regulator pressure substantially , by screwing the regulator cap down within 2 turns of the bottom. Still no Joy.

Is it my heater, or is it just normal for a Propex to be altitude challenged?

ps, at 7000 feet the heater works about 50% of the time. I am taking it to sea level next week, will update if that makes it reliable.

[Terran]

If it works half the time at a certain altitude, then it's probably not the altitude that's affecting it.

Look at it from a empirical standpoint. You're trying to isolate a single variable as a cause, altitude. But if altitude stays constant, and there are no other intervening variables, then your results should be the same every time. Put another way, it will either never light, or always light because the situation is never changing.

I'd fancy a guess that there's something else wrong. I don't know too much about the technical function of the propex, but i do know that burning propane is burning propane. It might not burn as efficiently at higher altitudes, but it should always burn.

Can you give us more details about the model of the propex / conditions when it will and won't work?
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[BoulderSyncro]

Have you replaced your regulator? My propex was acting funny (exactly like it was starved for gas intermittantly) all the time, but it was worse at altitude. I have two propane tanks. When I finally got the bright idea to use the other tank all of my symtoms went away, and the propex produced mcuh more heat. I am planning on replacing the regulator on the offending tank, but I guess it could be something else like a bad valve.

[jackbombay]

Propex does have a high altitude model, which leads me to believe that their "normal model" has problems at high altitude.

I would think less gas pressure altitude would be better than more, more gas and thin air = very rich AF mixture.
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[Texxxxx]

Well, I voted 'Yes', but I want to qualify it.

I used my propex at 8500' (Bodie, Ca) and it worked flawlessly all night long. When I crossed Tioga pass...approx 10,000 feet, I pulled over to see if it would work. I had read about people having problems at altitude. The propex lit right up and stayed on the whole ten minutes...lol...that I sat there.

I've used it many times...mostly between sea level (where I live) and 6000 ft., and it has always worked well.

I put in a brand new propane tank from GoWesty when I installed my Propex (VanCafe), as the heater was going into a GL, and have never adjusted the pressure.
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[FNGRUVN]

Hey Jon, I'm not sure what the altitudes have been(Bryce Canyon and Rocky Mountain Natl. Park to name two), but I'd guess it would have been above 9K and mine worked great. You must have got one that was built on a Monday morning or Friday afternoon. Sorry to hear you're having trouble.

[Outback Kampers]

[Outback Kampers]

[presslab]

I had problems with my HS2800, especially at altitude, until I bumped up the pressure from the normal 11" WC to 14.5" WC. It seems counterintuitive that the higher pressure would work better for high altitude but it did work for me.

I was able to get the higher pressure by stretching out the spring behind the LP regulator adjustment cap.
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[Terran]

[syncrodoka]

I have been interested in putting a propex in my hard top which means adding a propane tank of course. For this reason I have read and remember more than a few of these propex threads. Westyventures is the source for these units and Karl knows them well. Jon knows this from the previous threads that he has been a part of. It does seem like a waste of time to go out and ask questions that you know the answers to- go to Karl.

[Jon_slider]

thanks for your inputs

the next intervention, thanks to Karls ever patient and ongoing generous support, is to have him send me a pre adjusted regulator

My van has a new GoWesty tanks and regulator, but I have never undertaken, nor found anyone willing, to adjust my regulator.

Does anyone here know someone who can do it for me? I will be in Santa Cruz as of this weekend, until Syncro De Mayo..

Im going to test if the Propex is more reliable at sea level, but I have learned from this thread, not to send my Propex back to Karl, and to focus on the regulator adjustment as the next intervention.

[Jon_slider]

well..
I drove to Sea Level, and the Propex lights every time...

I still need my regulator adjusted to correct pressure to be sure its right..

anyone in Santa Cruz willing and able to help, or can you refer to a shop that can do it, before I take Karl up on the offer to ship me an adjusted regulator?

thanks
Jonathan the unRegulator

[tencentlife]

I don't know the make-up of the Propex or Espar and their capabilities so the expertts on them will correct me here I'm sure, but I have plenty of experience with gas refrigerators and other propane appliances at altitude. One thing that needs to be understood is that you never mess with a regulator. The delivery pressure is very small, less than 1 psi equivalent, and the burn mixture very sensitive to delivery pressure changes. To adjust it properly is the job of a trained gas technician who has and knows how to use a sensitive manometer. Do not attempt to adjust your propane regulator yourself, ever.

The other thing is that the air/fuel mixture has to be closely balanced to be safe for use in an enclosed area, and unless the unit has variable air mixing or variable fuel jetting and some kind of feedback, the actual range of altitude where it can sustain a balanced flame on a fixed gas orifice and fixed air mixing tube size has real limits. Once you're much over a mile in altitude, a sea level balanced burner may light, but that does not mean it is producing a balanced flame, and the result is production of dangerous carbon monoxide, the odorless and colorless and tasteless and lethal gas we all know so well.

If you have soot formation on the burner tube, chimney, or thermocouple, then the flame is not balanced. A balanced propane or NG flame produces no soot, and nearly zero CO. As a rough guide it should be blue with orange tips. The presence of yellow or white coloration in the flame is a sign of imbalanced combustion and potential danger. If an appliance has an adjustable air draft orifice then some field adjustments can be made there, using flame color as a rough guide, but depending on the appliance and its design, beyond a certain range of altitude actual jet changes may need to be made to compensate.
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[rockfish]

[Outback Kampers]

I respect the input here on the subject of pressure vs altitude, regulators, etc. However, Propex specifies that the unit operate on 30-37 millibar pressure which is higher than US regulators are set to. Although the heater will usually operate ok at stock US regulator pressure, it never reaches full efficiency, and we often see poor reliability at altitude.

Adjustment of the regulator (not a precision device by any stretch) is quite easy and safe, using a simple U-tube manometer constructed from clear plastic tubing and a scrap piece of lumber as pictured at www.propexusa.com . Neither the Westy fridge or the stove function is affected in any measureable amount by this increase in pressure.
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[Jon_slider]

Thanks Karl!

your manometer picture inspired me to take the plunge

I made a Milk filled Manometer

and set my pressure to 14 water collumn inches

Thanks to everyone for the support.

Now if anybody wants help setting their pressure I will be happy to help

Testing at Sea Level shows the Propex is reliable on the first try, every time.

I will update after I get back to altitude.. which will be after SDM..

[Outback Kampers]

[Jon_slider]

> is that merely white water or really milk?

mostly water, with a little half and half for food coloring

tip of the day.. I spent a lot of time at the hardware store looking for a threaded fitting to match my regulator output nipple for my fridge propane line..

it would have been much simpler if I had just bought hose with a larger enough inner diameter and just push fit it to the nipple.. I used half inch ID hose, it was too tight.. dont know the best size to use for a push fit, but bigger than half inch.. glad thats over

if anybody wants to use my milkometer at SDM, let me know and I will bring it along..

[tencentlife]

There ya go, Jon, now at least you're doing it right.

My post above was to stress that no one should go screwing around with the gas pressure regulator by trial and error. No, they are not delicate precision instruments, I've been inside regulators both brand new and 70 years old and they're all about the same, much like the very simple fuel pressure regs we have on our cars. Not rocket science, and not hard to do adjustments properly. I just wanted to point out, for safety's sake, why you should not play around with it until you know what you are doing, that's all.

I've been given exactly the same warnings by professionals who have made their careers working with this equipment, so I was just passing along good advice for the layperson.
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Shop for unique and useful Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/
also available at VanCafe.com!

Please don't PM here, I will not reply.

Experience is death to doctrine.