Our gas meter is rated 5" w.c. and 175 cu.ft/hr. We have two furnaces
rated 120k BTU/hr, 3.5" w.c. min pressure, 13.8" max. So that's all fine
and good. Now add in our Generac at 316k BTU/hr and 5" min, 14" max.
Obviously that meter isn't enough. But we're going back and forth with
our rep about pressure. She says we can get 1/4 PSI and a 425 meter. Or
2 PSI, but that has to go through engineering, and I fear it's going to
take a long f'n time.
So we need like 556k BTU. Is it safe to assume that we can get that out
of a 425k meter and accept the pressure drop (a little over 600k @ 2"
drop, I assume anyway)? The Generac demand regulator can't run lower
than 5", so I just don't know if the standard 1/4 PSI / 7" meter is
going to be enough. The generator is less than 20 feet from the meter
though. More like 12 feet.
Only one furnace is wired to the generator. However, I can see a
scenario where the generator controller wants to run when utility
voltage is sagging (starts at 192 volts or less), but the furnaces may
be fine at say 90VAC. So we could potentially have both furnaces and the
generator running at the same time. In reality, the furnace thermostat
that's on the generator will be cut off by one of the transfer switch's
smart contacts, so the furnace won't run. But we might have to disable
the lockout in the winter if power is out for days and the building
starts to freeze.
I'm thinking just do the 2 PSI delivery now in case we need a bigger
generator later, but I can't wait months for the gas co. to get their
heads out of their asses.
Probably should just call a plumber, but I'm lazy, and cheap.
