New furnace install

[Tstang429]

Ok hope I can get some help. I have someone willing and says they know how to install a propane furnace in the garage. Persons a general contractor I trust. But I like to learn myself and he’s not great at explaining. What I’m looking to learn and understand is plumbing the propane from a 100lbs tank to the unit. There are so many types of regulators it’s confusing ms then sizing the hose as well. It’s a 50k btu downflow from a modular home that we are installing in a 20x20 garage. Any help with how to plumb this would be appreciated.

 

[75gmck25]

For most natural gas appliances I've installed, the regulator is part of the appliance, so I assume it's the same for HVAC using propane. I'm not sure how propane regulators differ from natural gas, since most city NG operates at really low pressure.

I would have to look it up to be sure, but I think 50k but should be fine with 3/4" or maybe even 1/2" line, and you can mix black gas pipe and gas-approved flexible pipe. Use black pipe where it needs physical protection, and CSST where space is tighter and at the ends to make the connection easier.

The one confusing part I found when I installed a gas fireplace is that CSST gas pipe is made by different companies and the process for terminating (adding the end to the pipe) will differ between brands. If you buy your pipe from HD or Lowes you may get one brand of pipe and connectors, and when you go to the HVAC supplier it will be a different brand and different connectors. Both brands will want to you go through training and be "certified" to terminate and install their pipe. In my case, the end connectors were not interchangeable between brands.

 

[PoorUB]

For most natural gas appliances I've installed, the regulator is part of the appliance, so I assume it's the same for HVAC using propane. I'm not sure how propane regulators differ from natural gas, since most city NG operates at really low pressure.

Pretty much every gas valve will regulate the pressure, BUT there is a maximum gas pressure to that gas valve, 11" of water column for LPG, 7" for natural gas.

LPG tank pressure can be a lot, it varies with the outdoor temp, up to 150 PSI or more. There needs to be a regulator a the tank. This regulator can drop that pressure to 10 PSI, or all the way to 11" or 1/2 psi.

Often we will put a 10 PSI regulator on the tank, run a line to the building and put a second regulator on the outside of the building to 11" and run pipe to the appliance.

Sometimes we will put a 2 PSI regulator on the building and a third regulator, 11", at the appliance.

It all depends on your gas demands, and how how far you are running pipe. More pressure will flow more gas in a smaller pipe.

 

[fitter30]

Tank to furnace how many feet of pipe?

 

[Firebrick43]

PoorUB covered the basics pretty well.

More the specifics.

I work with Rego products everyday which is why I am going to site their products.

I prefer a seperate first stage and second stage in almost every situation but a twin stage will probably work in yours as well.

You will need to tie (2) 100lbs cylinders together to get good vaporization in your location when really cold with that BTU load. To POL hoses to a POL Tee, and then a POL pig tail to the first stage regulator.

First stage would be a compact LV3403TR9.

LV3403TR9

The output would be a 1/2NPT to 3/8 SAE flare (45 degree). 3/8 copper tubing for that BTU load would be sufficient as long as your not running 100's of feet.

At that point you would plumb into a second stage regulator such as a LV3403BR44

https://www.regoproducts.com/lpgproductpdfs/lv3403br.pdf

Vent facing down, black iron 1/2" schedule 40 stub out from the building 18" off the ground.

Clearances of the regulator to windows/AC/other ignition source



from that point 1/2 black iron schedule 40 with yellow Teflon tape and a good gas dope such as rector seal #5 or gastite should be used together IMHO. I would advise against CSST

At the termination point a drip leg should be plumbed and a 1/2 turn shut off. From the shut off use an appliance connector to the furnace. Piping needs to be leak checked before use. You really should leak test with a sensitive gauge/manometer.


Most all info is included in the serviceman manual.

https://www.regoproducts.com/PDFs/L-545_Servicemans_Manual.pdf