My Garage/Shop Heater Install

[Peter 315]

You said the pressure was 11.2 can you bump it up to 12 or 13

 

[BukitCase]

If you have a good DVM, hook the black lead to ground; set range to DC ONLY, and DEFEAT the auto range with manual range selected to around 100 volts - this should allow the meter to NOT see the several hundred volts AC, just concentrating on the approximately 20-30 volts DC, IF it's there - a good flame and flame rod will still bounce around enough to drive autorange CRAZY, hence the manual range/DC ONLY setting.

If all goes well, you should read around 20-30 VDC, but it can go as high as 100 at times. You should use alligator clips, NOT handheld. If this heater follows what I'm used to, that DC voltage will be NEGATIVE (RED lead clipped to center of flame rod, see pic in parts manual - 99% of my experience is with industrial stuff, but this looks like a baby brother so it might actually be true :laughing:

Sounds like we're gettin' to the meat of this... Steve

 

[dragoneggs]

You said the pressure was 11.2 can you bump it up to 12 or 13

Not sure I want to mess with that at the tank regulator. That was installed and set by the propane gas supplier. I would like to though because spec is 11 to 14. Thing is I am getting 9.5 at the outlet during the initial burning. Do you think that would drop significantly once running on its own?

 

[BukitCase]

Peter has another valid point, not all burners/flame rods are created equal :=)

is that 9.5 at the TANK outlet, or at the HEATER while it's trying to run?

 

[Peter 315]

Not sure I want to mess with that at the tank regulator. That was installed and set by the propane gas supplier. I would like to though because spec is 11 to 14. Thing is I am getting 9.5 at the outlet during the initial burning. Do you think that would drop significantly once running on its own?

Troubleshooting mentioned gas pressure to low or to high

 

[BukitCase]

Sounds like that spec is at the heater, not the tank -

"For propane: when the heater leaves the factory, the combination gas valve is set so that the valve outlet gas pressure for a single-stage valve or high fire of a two-stage valve is regulated to 10 IN WC. Low fire on a two-stage valve is set to 5.0 IN WC. Inlet supply pressure to the valve for propane must be a minimum of 11 IN WC and a maximum of 14 IN WC"

Any time there's flow, the downstream pressure will ALWAYS be less, so you may need to bump things up til you can measure AT LEAST 11" WC at the heater gas valve... Steve

And yes, flame shape AND volume will affect flame rod functioning. (I've never found a way to regulate 9.5" WC UP to 11" WC, only DOWN )

 

[dragoneggs]

Peter has another valid point, not all burners/flame rods are created equal :=)

is that 9.5 at the TANK outlet, or at the HEATER while it's trying to run?

9.5 is the manifold pressure. 11.2 is what I measured at the inlet to the gas valve in the heater. Also the same setting at the propane tank with 1/2in with about 15ft of black pipe. I could bump it up at the tank but worried the gas guy might realize I 'dicked' with it. But this is the only other thing I can think of... maybe bump it to 12.

 

[Peter 315]

Baby steps will get it going.......

 

[BukitCase]

Your next "baby step" should be to VERIFY that the flame rod is working, re-read post#112 - I've never seen one work (reliably) if it's putting out less than about 15 VDC - I won't walk away if it's less than a bit over 20... Steve

BTW, yours is EASY - try it on a car bottom furnace with 32 burners - adjacent burners can sometimes blow flame away from their NEIGHBOR's flame rod, it's really fun to work on the WRONG BURNER for a couple hours (Good thing I'm usually a "fool me once" kinda guy )

 

[ultrarunner]

My brother is on propane and when he bought the place as-is he said the furnace sometimes flamed-out.

Turned out when both water heaters fired the flow dropped enough for the furnace to stop.

I bumped the pressure and no more flame out