Thread: Garage hanging heater

This is a personal question some of you inspectors a bit more versed in HVAC maybe able to help me with. I picked up a Reznor XL140 hanging heater for my garage. Its Nat. gas. I hooked it up and and getting a slight blow back when it ignites. After that only three of the burners closest to the supply pipe on the burner rack ignite. (the standing pilot is on the farthest burner from the supply pipe). The "jet" of the flames seams pretty weak as well. I have a 2 psi residential natural gas supply. Are there heaters in the 120K BTU range that use a higher pressure supply? I cant find any info online for this unit as it is a bit older. I did note that the info plate states Nat Gas 3.5" and propane 11". Would that be a 3.5 lb supply needed? any thoughts would be appreciated...

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It sounds like you've picked up a second hand heater which could need cleaning, or it may have been converted to propane (smaller jets). Either way, I advise you to take it down and bring it to a gas heating technician for cleaning and inspection.

Originally Posted by Lanny Freng

This is a personal question some of you inspectors a bit more versed in HVAC maybe able to help me with. I picked up a Reznor XL140 hanging heater for my garage. Its Nat. gas. I hooked it up and and getting a slight blow back when it ignites. After that only three of the burners closest to the supply pipe on the burner rack ignite. (the standing pilot is on the farthest burner from the supply pipe). The "jet" of the flames seams pretty weak as well. I have a 2 psi residential natural gas supply. Are there heaters in the 120K BTU range that use a higher pressure supply? I cant find any info online for this unit as it is a bit older. I did note that the info plate states Nat Gas 3.5" and propane 11". Would that be a 3.5 lb supply needed? any thoughts would be appreciated...

Lanny,

I would not even venture to offer a suggestion. Blow back while not uncommon is unsafe and it should be checked by someone that can physically measure gas pressure, gas valve actuation, orifice sizing, gas line sizing, venting and a host of others things that I can't think of right now.

Are you really running 2 PSI gas pressure? That seems very unusual to me. And no 3.5" does NOT equal 3.5 PSI.

Brother, get help.

I did not install it yet. I disassembled the entire housing to make sure the heat exchangers and orafices were not clogged with debris or a mouse nest. All checked out. I just set it in my driveway and hooked up the gas and electric. No venting was installed at the time. I will see about having someone that specializes in these things take a look. thx

Originally Posted by Lanny Freng

This is a personal question some of you inspectors a bit more versed in HVAC maybe able to help me with. I picked up a Reznor XL140 hanging heater for my garage. Its Nat. gas. I hooked it up and and getting a slight blow back when it ignites. After that only three of the burners closest to the supply pipe on the burner rack ignite. (the standing pilot is on the farthest burner from the supply pipe). The "jet" of the flames seams pretty weak as well. I have a 2 psi residential natural gas supply. Are there heaters in the 120K BTU range that use a higher pressure supply? I cant find any info online for this unit as it is a bit older. I did note that the info plate states Nat Gas 3.5" and propane 11". Would that be a 3.5 lb supply needed? any thoughts would be appreciated...

Check those numbers/assumptions. Doubting 2 lbs. More customary residential average 0.2-0.25 at 6-7" w.c. after the regulator (which is after the meter). Where are you getting this information from? Call Minnesota Energy.

Sizing of supply piping, orafices, compatible regulation, this is not for the uninformed, or DIYer. Get yourself a professional gas fitter.

Installing used equipment without documentation is unwise and risky especially if you don't know the specifications, how to test, analyize, or adjust, let alone evaluate the equipment. Installing an undocumented USED furnace is IMO beyond stupid, more so when don't know anything about what you're doing.

Commercial and shared metered services can run higher pressures - need then intermediate regulators elsewhere to step down for RESIDENTIAL type appliances.

Suggest you consult a pro, and not install commercial equipment or used equipment that has no documentation or performance history/testing to your residence. Yes there are commercial grade and residential grade appliances with similar btu ranges. Why would you do this? What do you need 140K for? (its not 120K)?

If the unit was out for junk or scrap likely there was a reason, possibly due to being a quarter of a century old. Certainly wouldn't meet your local energy codes. 140K?!? for a residential garage?