No I live in the USA....you've just been doing it wrong since 1975.




"Stretch" wrote in message
oups.com...
26. Anthony Berlin Sep 9, 6:26 pm show options

Newsgroups: alt.home.repair
From: "Anthony Berlin" - Find messages by this
author

I do it for a living, and NG should be delivered out of the gas valve
at
10"wc.



Anthony,

I also do it for a living and have been since 1975. I have worked on
Lennox gas furnaces that list 8.5" WC as the manifold pressure on the
nameplate for LP furnaces. If Lennox designs it to run at 8.5" that is
what I set the Manifold pressure for. If there is no pressure listed I
use 11" WC. A few years ago I installed a Carrier gas pack and
installed a LP conversion kit. The kit stated the manifold pressure
was set for 3.5" Wc. I thought it was a typo and called Carrier. They
designed it for 3.5 Inches manifold pressure and the orifices were
sized to work at that pressure. I have seen atmospheric gas burners on
hgh pressure steam boilers for dry cleaners that were designed to work
at 4 inches water column manifold pressure.

If there is no rating on the nameplate, I use 11 inches water column
for LP and 3.5 inches water column for natural gas. This has been the
standard since at least 1975 in the USA. Do you live outside the USA
by chance? There might be different standards elsewhere. If the
manufacturers name plate says something else, then I follow the
manufacturers instructions.

Stretch