So I recently (finally!) setup a my shop with its own dedicated heat source -- a ProCom 75k btu unit with thermostat. One of the last tasks was to install the LP conversion kit and then adjust the gas valve to 1.0-1.5" WC. Tool for the job is a manometer. Not exactly something i keep around, but also something simple to build out of some basic stuff lying around my shop. I used a piece of leftover 8020 extruded aluminum, some 5/16" clear tube, a hose barb with 1/8" thread, a piece of 1/2" ruled log paper, double sided tape, and some dyed water (food coloring). I couldn't find another one on the web with 8020, so thought I'd share. It also stores neatly on its side. =)

1st four pics are rotated (stupid phone).

-Dan A.


PS: AT THIS POINT, I HAD NO IDEA WHAT THE MANIFOLD PRESSURE SHOULD BE. UNDERSTAND I AM NOT A TRAINED HVAC PROFESSIONAL, LOL.

That's cool. How do you use it ??

Never mind, I just looked it up lol.
http://www.rverscorner.com/manometer.html

Made a 2nd larger gage for the incoming LP pressure. Thought I had an issue but ended up just needing to bleed out the air more/longer out of the lines.

11" WC coming in from the regulator, and 2" WC flame adjustment on the gas valve (for efficiency and heat exchanger lifespan).

Good stuff!! Looking forward to some warm project space this winter.



PS: if you came here from a Google search and don't yet own a buggy, check out this site and the For Sale section!


PSS: AT THIS POINT I WAS STILL TRYING TO DETERMINE THE CORRECT MANIFOLD PRESSURE FOR LP.

Nice work, very nice shameless plug for the site. Well done.

Ha, thank you! I couldn't find crap for info on a shop heater install. It's like it's some kind of hocus pocus mojo magic or something (?). Turns out it's actually pretty effing simple!

Now if someone could go ahead and finish hanging the other 20 sheets of drywall for me. This was a winter project from...2 winters ago!

My heater was making a high pitch whistle-sound at the flame and flame seamed pretty orange.

So in re-reading my gas conversion kit instructions, I believe I made an error. The recommended incoming gas pressure is 11-14" WC and then no more than a 2" WC DROP at the manifold (not 2" WC pressure). The target pressure at the manifold is 9.5" WC at my altitude in 0-3500'.

When I re-measured everything I'm consistently getting 11.5-12" WC line pressure and 9-9.5" WC at the manifold. No more whistle + she blows more heat.

Also the heater fan (not exhaust) never shuts off. I've got 4 connections on my tstat when I should only have 3, hence the extra connection is triggering the fan to run constantly. Need to get a roll of 3-wire tstat wire to mount the tstat where I want it (not hanging off the heater with stereo wire like in the pic) and then will have this thing purring on its own. Gonna be 50's-60's next few days, so no hurry.

Oh the joys of DIY!

Two more new issues to remedy:

#1) Regulator is freezing up. Either [A] the regulator isn't big enough (rated for max 75k btu, but my heater is a 75k btu), or [B] I need to tilt it down more so the vent will actually vent (it's horizontal now, but vent hole is on bottom and faces sideways and not down). I have another regulator rated up to 200k btu, but its an indoor type and therefore requires some plumbing changes. My once-worked-for-a-furnace-company-buddy tells me the bottles can freeze u if you use them on a day that was significantly warmer than the day the bottle was filled. Filled it when it was 34, and it was almost 60 out when I fired up the furnace a couple days later.

#2) Had almost a whole day of wind and rain which blew into the vent cap, down the vent duct, and created a small 6" wet spot on my barn floor. Not sure I can do anything about this one. Hoping it doesn't rain with 35mph gusts very often.

I believe you could vent it horizontally out the wall and slant it down so the rain would run out.

The horizontal vent kits cost as much as the dang heater, lol!

I'm replacing the vent elbow on the back of the heater with a tee that's got an aluminum cap on the bottom. It collect about 3-4 cups of water before it can run into the heater and onto the floor. And when it runs it'll burn off.

Also picked up an outdoor 2-stage 11" WC regulator with a huge vent port rated to 225k btu. No more freezing the regulator.

Another $50 of upgrades, but 100% necessary. That should about do it.

*DELETED*

The best advice I have for anyone installing the heater is to read the instructions, lol!

The LP supply pressure needs to be 11-14" WC.

The manifold pressure for my heater should be 8.5-9.5" WC. I'm getting between 8.5-8.8" WC.

ALSO...don't forget all of the parts in the NG-to-LP conversion kit. There should be a change made at the manifold as well as the burner orifices as part of the kit.

Spent all day in a 60'F shop while the high outside was 11'F. Unfortunately for this site, i was working on some built-ins for my house. Wife's priorities rule.