Hi, back again with more on the Daikin install. This, by the
way, as kind of a sideways comment on the "inverter" thread,
is a 1.5 ton inverter-driven system with an upright air-handler
designed basically as a forced-air furnace replacement. Daikin
was apparently first to market with this sort of thing and the
other makers are *just* starting to get on board with that idea.
As more furnace owners start wanting to move to high-efficiency
heat pumps, I figure there's going to be a huge market for those.
Anyway, today we finally fired the thing up and got it running.
What bothered me is this: the Daikin install manual is up one
side and down the other with a 12-hour leak test at high pressure
with nitrogen, followed by at least a 2 hour vacuum to 500
microns before even *thinking* of cracking the valves to let
the juice out of the condenser. My tech instead hooked up
the vacuum pump and took 'er down to something in the
neighborhood of -13 psig, didn't even have a micron scale
going, and maybe left it there for half an hour. Then, cracked
one valve and then the other to let a little refrigerant in, saying
that just allowing that to come up to 80 PSI or so in the lineset
was "pressure test" enough. Within about ten minutes he had
opened the valves all the way and was trying to start the unit.
I could easily see the "proper procedure" in an install manual
viewed as unnecessary overkill in the real-world industry, but
here the pendulum really seemed to have swung the other way
into very little care given to getting the lineset and evap nice
and clean. Oh, and this was after brazing it onto the AHU
without flowing any nitrogen at all, just put the pipes together
and torched 'em. So does this throw everything I've been reading
about careful startup procedure out the window, or was this guy
genuinely careless on my job? Is it any different with the newer
types of units, i.e. is it okay to leave out what I'd expect to be
normal parts of the procedure for certain types of unit? I don't
think this fella even *owns* a nitrogen bottle.
As a side note, it was clear that he'd never started one of this
particular type of Daikin, as it's got a hard requirement that you
put it through a special test mode once before it will run
normally. Both of us sat there reading the manual and the
paper on the inside of the unit cover until we figured out how
to get the test to run, and all *kinds* of fascinating things
happened in there once it started. Hearing/feeling the compressor
gently ramp itself up and down but really quietly is pretty cool,
and right there's one of the benefits of the inverter systems.