High Altitude Water Heater

[dougemil]

i'm shopping for a power vented LP water heater and recently found one that is rated for up to 7,700' of altitude. anybody know what's up with that? i've never seen a water heater rated for altitude before but am interested because i live at 9,300'.

 

[Jay H]

I'm guessing it has to do with the LP... LP is pressurized in a tank that gets delivered to you at some interval. At elevation, the reduced air pressure and the colder temps affects the pressure of the propane feeding your water heater such that either the propane (in liquid form) doesn't gassify properly or efficiently, leading to either an inefficient burn (if it burns at all) to either a low simmer versus a nice flame.

At least this is coming from a mountaineering standpoint and trying to burn canister stoves at altitude which are an isobutane mixture. I am not an expert in water heater systems but my guess is the physics is roughly similar.

Jay

 

[Highbeam]

Air is less dense at altitude and has less oxygen per cubic foot to burn. If you tune a water heater to burn nice and clean at sea level and then go to 10,000 feet then the flame will burn yellow and rich because there is too much fuel and not enough oxygen. A high altitude burner will have smaller orifices to release the gas or use a lower pressure regulator to accomplish the goal of limiting fuel.

The vapor pressure of LPG will be a little bit different in the tank at altitude but the pressure regulator will fix that before being introduced to the water heater.