Gasoline Webasto at altitude

[hbn7hj]

Originally Posted by booster

One thing you need to remember that has not been mentioned is the any, and I mean any, time you have a pressurized combustion chamber you hugely increase the risk of CO poisoning. In furnaces in general it is against the safety rules, and probably many laws and codes, to have a positive pressure difference between the combustion chamber inside and outside. It doesn't matter if the pressure difference if from a positive chamber pressure or a negative circulation fan pressure. That is why you always see the combustion fan on the discharge end of the combustion chamber and the circulating fan on the inlet side with no restriction before the heat exchanger in you home or commercial high efficiency furnaces or water heaters.

The Webasto blower is definitely before the combustion chamber. Chance of a leak in the casting is slim but they are really uptight about new gaskets when you take it apart.

I know a guy that designed natural gas pipelines for a living. He can probably solve the thermo problem. I have no intention of making a pressurized combustion chamber but it would be nice to know if we have enough energy to do it.

A furnace is steady state so throttle response not required.

Come on Velit. Give us something to tear apart.

[booster]

Originally Posted by hbn7hj

The Webasto blower is definitely before the combustion chamber. Chance of a leak in the casting is slim but they are really uptight about new gaskets when you take it apart.

I know a guy that designed natural gas pipelines for a living. He can probably solve the thermo problem. I have no intention of making a pressurized combustion chamber but it would be nice to know if we have enough energy to do it.

A furnace is steady state so throttle response not required.



I think you will find a furnace is not steady state as the pressure seen on the inlet air can change based on wind direction at the air inlet, barometric changes if a front comes through, etc. It may also change with the energy content of the fuel, which could change with each tank of gas.


Come on Velit. Give us something to tear apart.

It certainly would not be hard to pressurize the combustion chamber, but just not a good idea IMO.



I am pretty surprised that they have the fan on the inlet side, actually, as that does mean you have a pressurized combustion chamber now.


Cast iron chamber is no guaranty against leakage or cracks. I had a 50s vintage GE furnace that had a cast iron combustion chamber for forced air furnace. It developed a crack by the mid 70s. Since it was a forced air furnace and the fan was before the chamber the pressure outside the chamber was higher than inside as it didn't have a fan forced combustion air that was at atmospheric.


Some very early high efficiency closed combustion home furnaces had the fan on the inlet side and they had all kinds of issues with leaks and pulled them off the market very quickly.


Having the fan on the exhaust side is much harder as it has to survive the high temps and corrosive exhaust gasses and condensation. In a van I suppose you would also risk having it freeze up in cold weather also when not running.

[hbn7hj]

It is cast aluminum. They have been on the market for many years so they have pulled it off. Now I understand why they are so uptight about new gaskets at maintenance.

[GeorgeRa]

Originally Posted by booster

…….

I am pretty surprised that they have the fan on the inlet side, actually, as that does mean you have a pressurized combustion chamber now.

Cast iron chamber is no guaranty against leakage or cracks. I had a 50s vintage GE furnace that had a cast iron combustion chamber for forced air furnace. It developed a crack by the mid 70s. Since it was a forced air furnace and the fan was before the chamber the pressure outside the chamber was higher than inside as it didn't have a fan forced combustion air that was at atmospheric.

Some very early high efficiency closed combustion home furnaces had the fan on the inlet side and they had all kinds of issues with leaks and pulled them off the market very quickly.

Having the fan on the exhaust side is much harder as it has to survive the high temps and corrosive exhaust gasses and condensation. In a van I suppose you would also risk having it freeze up in cold weather also when not running.

Installation manual for my Eberspacher D2 heater was very specific with limitations in exhaust and intake lengths, diameters. Recirculating air ducting is also restricted to maximum lengths or total degree of bends. Fuel line restriction is also critical and well specified. These heaters are very finicky, well installed ones have issues with fuel flow, air bubbles in fuel flow, carbon deposits. Incorrectly installed heaters are nightmares. Unwanted pressure changes can to extinguish open flame combustion.

I didn't hear about leaking combustion chambers, they are about ¼” wall aluminum castings but many DIY folks install CO monitors including myself.

[booster]

Originally Posted by GeorgeRa

Installation manual for my Eberspacher D2 heater was very specific with limitations in exhaust and intake lengths, diameters. Recirculating air ducting is also restricted to maximum lengths or total degree of bends. Fuel line restriction is also critical and well specified. These heaters are very finicky, well installed ones have issues with fuel flow, air bubbles in fuel flow, carbon deposits. Incorrectly installed heaters are nightmares. Unwanted pressure changes can to extinguish open flame combustion.

I didn't hear about leaking combustion chambers, they are about ¼” wall aluminum castings but many DIY folks install CO monitors including myself.

I am certainly not up on this kind of heater, but have considered the possibility of replacing the Suburban propane unit with one to get it on gas instead of propane. In reality I doubt that will happen as we don't use the furnace enough to get irritated by having to find propane often.


What I truly don't understand is why they have the combustion fan on the inlet side these days, especially on the forced air styles that would put a leak right into the forced air into the van. Even our old school Suburban has the combustion fan on the exhaust side, right as it exits the unit.


I looked at a few of the schematic drawings for various brands and they all seemed to use the same setup on the inlet side which I think goes back decades without any real change.


I would think the somebody would modernize the design. Put the combustion fan on discharge end, add a wide band (lambda) sensor on the exhaust that controls the fuel volume to hold stoich and have a safer and probably sootless setup. Maybe it isn't that easy?

[hbn7hj]

It is certainly a better performing furnace than a Suburban. Just quietly humming away revving up and down as needed drawing gasoline from a 55 gallon tank.

I can’t find a place to install one in a Roadtrek as it takes a 4” hole through the floor and an under floor open area. Roadtreks are pretty well packed underneath. One guy removed the propane furnace and installed one, plumbing it to the side. I will not remove the propane furnace.

As it is I will not use it above 7000ft but in all other aspects it is a superior furnace.

Is anybody gonna spring for the Espar $2500 altitude furnace?

[GeorgeRa]

Originally Posted by booster

I am certainly not up on this kind of heater, but have considered the possibility of replacing the Suburban propane unit with one to get it on gas instead of propane. In reality I doubt that will happen as we don't use the furnace enough to get irritated by having to find propane often.


What I truly don't understand is why they have the combustion fan on the inlet side these days, especially on the forced air styles that would put a leak right into the forced air into the van. Even our old school Suburban has the combustion fan on the exhaust side, right as it exits the unit.


I looked at a few of the schematic drawings for various brands and they all seemed to use the same setup on the inlet side which I think goes back decades without any real change.


I would think the somebody would modernize the design. Put the combustion fan on discharge end, add a wide band (lambda) sensor on the exhaust that controls the fuel volume to hold stoich and have a safer and probably sootless setup. Maybe it isn't that easy?

Having a single motor driving both fans reduce the cost and forces same RPM for all heat outputs from low to high. Combustion pressure is rather low, I am basing this on exhaust outflow length, a few inches clearly visible during startup with water still coming as mist.

Hydronic heaters from all these manufacturers have two motors, one for intake fan just like air heaters and separate one for a fluid pump to pump it around combustion chambers. Hydronic heaters tend to be more expensive. Eberspacher, Webasto and likely Russian ones use DC motor with magnetically coupled impellers, foolproof.

[hbn7hj]

It is a four hour job for me to decoke a Webasto. Most of it R and R. About 30 minutes to clean it up and put it back together. It cokes up really quick at 10,000ft.

The Russian source Heaters4you is gone. FYI

[GeorgeRa]

Originally Posted by hbn7hj

It is a four hour job for me to decoke a Webasto. Most of it R and R. About 30 minutes to clean it up and put it back together. It cokes up really quick at 10,000ft.

The Russian source Heaters4you is gone. FYI

My heater is under the passenger seat, so, it is a job to get access to it.

Timberline by Elwell is using Russian furnace, I assume they are still getting it someway. Their control i integrated with Russian electronics, could be difficult to change to Espar or Webasto. I think Winnebago is using Timberline.

If I would be doing conversion again, I would likely go for the new US made water/space heater combo powered by LPG.
https://rvbusiness.com/aqua-hot-anno...-water-system/

[hbn7hj]

If Velit doesn’t come across I’ll probably try the Espar. I’m above 9000ft three months of the year and these furnaces are so superior to Suburban I am spoiled. I am at 900ft at the moment and all is well.

I would expect Webasto will eventually come across.

We have all learned something from this exchange. Thanks. Gotta think twice about reusing old gaskets. A pressurized combustion chamber is definitely a potential danger.

[GeorgeRa]

Originally Posted by hbn7hj

If Velit doesn’t come across I’ll probably try the Espar. I’m above 9000ft three months of the year and these furnaces are so superior to Suburban I am spoiled. I am at 900ft at the moment and all is well.

I would expect Webasto will eventually come across.

We have all learned something from this exchange. Thanks. Gotta think twice about reusing old gaskets. A pressurized combustion chamber is definitely a potential danger.

I got a few items from Heatso, quick shipment and low cost. https://www.heatso.com/espar-airtron...btu-heater-kit

[hbn7hj]

Let us know the results after a couple of weeks around 10,000ft. I expect we will hear from Webasto soon.

I assume they did not super pressurize the combustion chamber. Must have improved the fuel delivery system.

It does seem possible to pressurize the combustion chamber safely. It would be one lawsuit from failure. Maybe it would need it’s own leak or CO detector downstream of the heat exchanger.

We still don’t know how Velit is getting to 16,000ft.

[GeorgeRa]

Eberspacher S2 is good to 10,000' with auto adjustment and it has brushless DC motor. https://heatbreeze.com/chinese-diesel-heater/

[MsNomer]

Which is why we are willing to gamble on the VeLit. We need 11-12,000.

[GeorgeRa]

Originally Posted by MsNomer

Which is why we are willing to gamble on the VeLit. We need 11-12,000.

If in doubt looking at details of plastic molds helps to digest the original source. Plastic molds are expensive and it seems as all Chinese heaters use the same molds like for example Vevor. https://www.vevor.com/diesel-heater-...c18dd3a37e26.1

Installation and user manual seem as done by a limited capability translator, see manual last page:

7.5 The heat exchangers and exhaust pipe cannot be used for more than 10 years. Upon expiry, the replacement must be genuine parts, which will be replaced by the heater manufacturer or their authorized personnel. The composite sensor must be replaced at the same time.

7.6 During welding operations to the vehicle, the positive end of the heater should be removed from the battery and properly isolated to prevent damage to the control unit. During transport, storage, the heater’s ambient temperature should not exceed - 40 °C to 85°C.

..expiry... this is old British
...welding operation in lieu installation, pick any language.

The manual and their site doesn’t give me a comfort of paying even $650.

[hbn7hj]

You didn’t read the original Japanese Motorcycle owner’s manuals in the 70’s. What a hoot they were. Yep, the Velit is based on a Chinese POS.

Webasto doesn’t work for us at all. $2k+ doesn’t interest me too much. I’ll gamble with Velit. If they don’t deliver, so be it, if they do then we will give it a shot.

In thinking about the pressurized burner CO problem all potential leaks are upwind of the CO generation. Other than a casting crack should be pretty safe. Sheet metal Suburban heat exchangers would be more likely to have a CO leak. A crack in a POS Chinese casting is another issue.

I hope they are pressurizing the combustion chamber.

Let us know how your’s works. We will let you know how our’s works if we get the chance.

[MsNomer]

From larry barello on the PM forum:

"If Velit ends up a scam it's due to incompetence, not greed.

I met with Will and partially disassembled one of two prototypes he brought over. Of course they use an existing product, it would be dumb to reinvent the basic mechanic that has been cloned for so many years. Will/Velit, aside from finding a higher quality base manufacturer, modified/engineered the burner cup, blower fan and completely replaced the controller with his own design.

Maybe I was being scammed. I am an engineer and WTF do I know. We talked engineering, cash flow, supply chain, UX/UI, and the difficulties of bootstrapping a company from nothing. He sure sounded like a guy who actually uses the stuff wanting to bring a better product to market"

[booster]

Originally Posted by MsNomer

From larry barello on the PM forum:

"If Velit ends up a scam it's due to incompetence, not greed.

I met with Will and partially disassembled one of two prototypes he brought over. Of course they use an existing product, it would be dumb to reinvent the basic mechanic that has been cloned for so many years. Will/Velit, aside from finding a higher quality base manufacturer, modified/engineered the burner cup, blower fan and completely replaced the controller with his own design.

Maybe I was being scammed. I am an engineer and WTF do I know. We talked engineering, cash flow, supply chain, UX/UI, and the difficulties of bootstrapping a company from nothing. He sure sounded like a guy who actually uses the stuff wanting to bring a better product to market"

I am not saying anything is a scam or not but I do have a bit of experience in dealing with invented or majorly improved existing products, including the presentations by the inventors. I am also an engineer, mechanical/manufacturing.


One thing to remember is that nearly all inventors believe thoroughly that their idea is nearly perfect and better than all others. It comes with inventive mind, I think. Many, but not all, are also very good at presenting the product and the theory behind it. But, and this is the one that counts, is that until you get independent or self done testing of it under the conditions it is going to see all the rest is speculation and anticpation. In this kind of thing, in business or as an individual, you always have to be a bit skeptical until the testing is done, IMO. I would guess, in my history of dealing with this kind of stuff, well under 50% of modifications of existing products is successful, and clean sheet inventions are a fraction of that.


In the case of a product that can, literally, kill people and destroy property I would be even more vigilant.



To make sure a heater works at altitude, in very cold weather, without sooting up, without blowing out, and probably a bunch of other stuff I don't know about, including being foolproof safe you have to be cautious and at least a bit of skeptical, IMO.

[GeorgeRa]

Originally Posted by booster

.....................
To make sure a heater works at altitude, in very cold weather, without sooting up, without blowing out, and probably a bunch of other stuff I don't know about, including being foolproof safe you have to be cautiois and at least a bit of skeptical, IMO.

Agree.

This is an extensive discussion about Espar high altitude solutions. A lot of folks on that discussion are engineers. https://sprinter-source.com/forums/i...threads/63606/
For old Eberspacher units there are 3 solutions:

1.Make sure there is no obstruction on inlet and outlet to the combustion chamber, is installation within given guidelines.

2.Lower volume per stroke pump. Installation of two pumps in parallel with simple switch could be an easy solution.

3.HAK (pulse frequency control based on altitude)

The first two are valid for any heater, Webasto or others.

HAK devices are getting difficult to get as all new Eberspachers have altitude compensation built in.

Dennis from Lindenengineering states:
“You can get a HA pump from Summit in Commerce City
They are an off shoot of ATTP & Transwest.

Just off of Hwy 70 east of I 76 and west of Brighton Blvd they keep these in stock'
The pump is good up to about 11,000 ft when it too will start to cause the heater to cut out usually with flame outs !
All the best
Dennis”

[MsNomer]

We took a chance on the 2014 Promaster—ours is one of the first 5,000 built. Just turned 200,000 miles with no major issues. $650 is much less to risk.