Propex HS1800 vs Carver P4

[chase4food]

I have both a Carver P4 and a Propex HS1800 propane furnace. I took some video clips of both in operation with my iPhone together with a Radio Shack sound level meter. All segments of the video were captured with the same smartphone and unedited.

I bought the Carver P4 in 1999, and the Propex HS1800 in around 2000.

The time segments of the video:

00:00 - 00:27 Propex comfort air sound level
00:27 - 00:38 Propex exhaust sound level

00:38 - 01:11 Carver comfort air sound level
01:12 - 01:33 Carver exhaust sound level


Link


I have written a post on this:
http://eat-drink-men-women.blogspot.com/2016/03/carver-p4-furnace-for-isolde-part-4.html

And a tear down first look of the Propex, and a more detail analysis of the Carver design:
http://eat-drink-men-women.blogspot.com/2016/03/inside-propex-hs1800.html
http://eat-drink-men-women.blogspot.com/2015/04/carver-p4-furnace-for-isolde-part-2.html
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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[canasync]

I have never been impressed with the noise level of the Propex heaters myself and always laugh when I see an add that states how quiet they are. I would be interested in seeing how their newer model with the extra insulation compares.

I run a fully rebuilt Espar BN4 in my van. It's a little more bulky than the Propex or Airtronic heaters and has about same noise level as a Propex but puts out about twice the btu's and I'm into it for less than half the cost. The biggest drawback to my BN4 is the power consumption as it uses twice the amps of the modern heaters.

I don't know of anything on the current market with the low noise output, compact form, and low draw of the Carver but sure wish they'd come out with something like that again.
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[chase4food]

[michaelasnider]

I've only heard that the HS 1800 was noisy, and sound levels have been reduced.

I have a HS2211 (mounted externally) and it is very quiet. The vent is right by my head when I'm sleeping and it does not bother me at all.

[chase4food]

[chase4food]

When Truma acquired Carver company shortly after the release of the P4, I thought at the time they will integrate Carver's design into their heaters. Now 15 years later, their heaters look very much unchanged as their original own Truma's. You can tell by the unique housing. In this internal depiction it too is one motor design, and a stainless steel heat exchanger very similar to that used in Propex's. It looks to me now like they eliminated a credible competition that had a superior product by buying it out and buried the design.

Propex burner/heat exchanger; note the similar location of the flue exhaust port

Carver burner/heat exchanger housing - which is one of many elements of the whisper quiet operation

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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[chase4food]

I want to share the finesse operation cycles of the Carver P4 furnace. To cite how quiet it is and how much or little current consumption cannot convey how it was designed to work in the most efficient and unobtrusive ways. It is worth noting that recording video with a common consumer electronics the sound level of the audio cannot be trusted to gauge the true level in situation. These devices, such as the iPhone used here implemented automatic and dynamic recording volume control. The algorithm continuously strives to capture the faintest bits of sound even when it is dead silent. In this video the iPhone really "amps" up the recording volume as it was very quiet in the cabin.

00:00 - 00:17
Comfort air circulation fan runs at a murmur still outing warm air from the residual heat of the cast alloy heat exchanger from the previous burner cycle.

00:18 - 00:32
One of the two micro-controller decides a "call for heat" cycle is required to maintain target cabin temperature; pre-purge ensures; the current jumps from 180mA to 320mA because the combustion blower starts but modulated to very low speed.

00:32 - 02:50
Gas valves (there are two in this mode) for the high BTU setting open and immediately followed by the spark ignition; you can hear the faint pop as the flame ignited; the current ramps from 320mA to 380mA due to the increase load of the gas solenoids. The burner blower also speeds up and the current steadily increases quite quickly, for to around 750mA. Note that during this time the comfort air blower is still running at a murmur, as there is no need to waste energy running it any faster, because the heat exchanger has not built up in temperature quite yet.

02:50 - 03:26
By about 02:45 the current creeps up to 770mA as the comfort air blower speed is modulated up ever so little to transfer more heat energy from the heat exchanger into the cabin. At 03:25 one of the two microcontroller turns off the burner, and the current drops rapidly to 190mA.
03:26 - 04:11 There is a lot going on here. It just coincidental in this situation that when the burner is switched off, the comfort air blower is being modulated up to manage the heat energy that is stored in the heat exchanger by transferring the heat into the cabin, but not all at once in a short time. Because the spread of the actual cabin temperature and the target cabin temperature is small (not super cold outside the Vanagon) the blower fan runs at the murmur, and consumes 190mA.

Note: Please select to play in "720pHD" to see the texts in the display


Link


As you can see in this complete combustion cycle (with the furnace set to high, 2200W), the maximum current consumption is only 750mA, and only when the burner is running at a steady state. There can be time that the entire furnace consumes close to 1.75A, if my memory serves, when the outdoor ambiance is extremely cold, and the burner on cycle duration is very long. During this situation, the comfort air blower also runs at higher speed to transfer much more heat energy (per unit time) from the heat exchanger into the cabin air.

The micro-controller that manages the speed of the comfort air blower by monitoring the temperature downstream of the heat exchanger at the outlet air vent.

This is just one specific combustion cycles out of many possible permutation, dependent upon the temperature spread of the actual vs target, and the rate of heat loss out of the Vanagon.
_________________
- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[chase4food]

I apologize for the crappy video. I composted my blog post and then this forum post using the video that I rendered with Sony Vegas editing software. I view it on my computer and wrote the post, while waiting for the upload to Youtube. I should have know better that Youtube upload manager will apply video quality optimization as well as compress the size of the clip to shit!

Because the ambient light is so low, the crappy Youtube "video optimization" algorithm made the display totally intelligible.

Let me go and try to see if I can sort that out, by outsmarting the stupid upload manager.
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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[chase4food]

Update:

It turns out the Youtube Video Manager uploader and optimization algorithm is not at fault. While it softened the video somewhat, the texts in the display are quite legible. The problem is that embedding it in the forum post it defaults to SD, as opposed to HD. Playing in SD simply does not have the resolution to resolve the small texts.

There is a way to force it to play HD in my own blog but I don't think I can do that here without help from a moderator to go under the Samba's hood.

So the work around for the viewer to manually select "720p HD".
_________________
- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[westyventures]

Just stumbled on this again. On the bench, the HS2000 with no ducting at 12" away runs at 65 dBa. The HS2211 in the same conditions, 60 dBa. I now have acoustical ducting which lowers that by a solid 10 dBa with a 30" piece - that's significant! Barely audible, just a smooth whisper. The 2211 uses a molded composite fan volute which contributes to the decreased sound levels. Oh, and Carver, long gone so there is nothing currently comparable.

[chase4food]

[westyventures]

[westyventures]

Truma E2400 just for comparison.

External PCB, dual jets for high and low output, and very quiet operation - although I have no sound testing done at this point. This is the only other blown-air propane furnace available outside of the traditional crude US-made RV units.

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[chase4food]

[westyventures]

FWIW, the HS1800 design you 'compare' is 12 years old.

The 'Carver' is no longer made so is no longer an option for anyone. It doesn't matter one iota what is does 'better' or not.
Propex has made improvements to their design as has Truma. Go build you own heater and market it, then let's talk. But crapping all over a product I market with no current knowledge of the current versions, that's just over the top. I don't spend my time trying to destroy your livelihood and I expect the same. Thousands sold in many markets, Propex has stood the test of time and is still growing.

[Corwyn]

I know I'm going to get hollered at for saying this, but how soft does your bed have to be to go camping? How quiet does your heater have to be to sleep? Is your porridge too hot or too cold? Man up.
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[chase4food]

Manhood is too overrated. A lot of women are way tougher. Just look around the world at countries where women are still being oppressed. I see you are rough camping with an automobile.
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- Vince 飲食玩睡

what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei

[Corwyn]

[danfromsyr]

I think that points don't exist within the world that cheese4food operates within..
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[chase4food]