For reference, the max pressure of my "low pressure" burner, is 0.5psi , at least that's what the regulator says.

Wow, I never would have thought you'd find silicone in the internal loop of those sensors. Somewhere in the last week, maybe it was that ABP datasheet, I remember reading something about o-ring seals. I think maybe they had the dimensions you'd need if you were going to use them.

This may work for getting outside of the project case:

Through-Wall Straight Connector, 1/8 NPT Female

Straight Adapter for 1/8" Hose ID, 1/8 NPTF Male



-J

Yeah, it was the datasheet that talks about using o-rings -- page 37. It complicates the design slightly in that you have to secure the pressure manifold and potentially a ring retainer to the board and case, but doable.

aabud wrote:For reference, the max pressure of my "low pressure" burner, is 0.5psi , at least that's what the regulator says.

Wow, I never would have thought you'd find silicone in the internal loop of those sensors. Somewhere in the last week, maybe it was that ABP datasheet, I remember reading something about o-ring seals. I think maybe they had the dimensions you'd need if you were going to use them.

Worked like a champ with actual gas:
Now to start working on my servo that I'll use to turn the needle valve. The goal for me is to send a desire KPA value from Artisan to this arduino, and have it dial the needle valve to that KPA value.

ira wrote:I don't like the hose stretched over the 1/8" fitting and wouldn't use that long term. I'd try soldering a piece of close fitting brass tube into the hole in that fitting to get something closer to the right size. and if that's to small, you can just solder another piece of brass tube over that.

Ira

Good idea - here's version 2 of the adapter - had to make the last quarter inch of the nipple just a whisker bigger, but then a 1.8mm (od) brass tube was a good snug fit. Soldered in place, seems good and air tight - passes a soap test with lots more pressure than it will see in use.

Much better, now you just need a couple more soldered loops to make sure it stays lined up and doesn't pull free or maybe a loop of hose for strain relief.

Ira

Slightly off topic here, but I am likely going to go with an Omega Engineering pressure transducer for measuring boiler pressure.

Pressure sensor combined with servo to control the gas:

jpbbden wrote: It'd be an interested homebrew project, but I've settled on the 267 Series from Setra and am just waiting for one with suitable range to show up on ebay.

@jpbbden Any update on the Setra 267? How's this working out for you?

I'm looking to do the same thing. Been scouring the forums looking for tips. This thread is pretty insightful. Like you, I've identified a handful of options, namely those from Dwyer and Sensocon. The big wild card is how compatible these are with propane. One guy I've been in touch with has been use a Dwyer indicating pressure transmitter, and it's been working pretty well for years. Dwyer has ones similar to the Setra 267, but I need to compare the specs.

@Arlo - rather than wait for that Setra to show up on eBay, I ended up doing something similar to @aabud and designing my own equipment that uses an Amphenol AllSensors ELVH differential pressure sensor. I'm operating at natural gas pressures (they make ELVH series sensors that can handle propane pressures) and am getting really steady data at a precision of .01 mBar and a sample rate of approximately 3 Hz. My software samples at about 90Hz, but averages approximately 30 readings to smooth things out.








I still have a handful of the PCBs I had made to handle the Modbus communication and OLED display output (tying everything together). They are populated with the RS-485 transceiver, and connector, but not the ESP8266 D1 Mini, OLED, or pressure sensor. I also have CAD files for the enclosure and information about getting the process stream into the sensor. These work for differential exhaust airflow too, provided you use an ELVH in the correct range. If anyone is interested in a PCB please send me a DM -- I can't make any warranties about their suitability for use, but I'll do what I can to help.