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.
call the owner and complain yes he was careless .and dumb to do it like that as he was being watched by the person that just cut a big check and had the install manual in his hand
Unfortunately, the guy *is* the owner ... who offered the usual
sort of "been doin' this for a lotta years, it's fine" excuse. Yes, I
*did* ask before he started -- not really insistently, since he's
supposed to be the pro, but trying to get a sanity check. Hmmph.
Well, I'd like to collect a bunch of y'all's opinions on this and get
a feel for how lax one can be about this kind of thing and not be
back repairing a unit in six months or a year. And this is R410a,
of course -- that's more sensitive to contaminants, right?
These systems are not your "usual" systems. There are a lot of special requirements; the pressure tests, flowing nitrogen (which is good practice regardless) and a good vacuum critical because there are NO filter driers to catch the contaminants. Think of running your car engine without an oil filter.
What you can do now that all of this has already happened is a good question....I hope someone has some phone numbers that you can call and get a resolution to your issues.
Call the manufacturer and ask them what there opinion is of the lack of procedures followed. They will be faced with the warranty cost.
Originally Posted by hobbit
gope this guy was dankin sertified or they will have nothing to do with it
there is a two part class for these units
instalation class and a service class and the service class i went to was involved and technical
there are reasons they want it done thier way as was explained already
i feel in this case the only option is to recover all the refrigerant and fill the system with nitrogen and then a evacaution to 500 microns
if he wont do it then maybe dankin will step in and find someone that will
been doing this a lot of years doesnt mean a thing if you been doing wrong
It is always frustrating to me to read a post such as this from such a smart homeowner who still has something like this happen. The residential HVAC industry is a free-for-all joke. Do a google map search for HVAC contractors in your area, then do a google search for BPI certified HVAC contractors and you will see the numbers go from hundreds to single digits. I did it for for the state of Texas and I came up with about five BPI certifed HVAC contractors. I believe this method is the best to sift the chaff from the wheat.
The old "I've been doing it this way for 25 years is why over 50% of A/C systems in American are oversized by as much as 1 to 2 tons, and only 1 in 10 duct systems are sized & designed properly enough to allow the new high efficicency systems to operate at even 80% of their rated levels.
An answer without a question is meaningless.
Information without understanding is useless.
You can lead a horse to water............
I looked at bpi.org and it came up with a list of contractors
in my area which *all* say yes, they're certified for all possible
aspects, building-analysis, manufactured housing, heat/hvac ...
I'm not sure I quite buy that when there's apparently no
distinction across the entire listing. I'll bounce all this
[and several other system-specific questions I now have] off
Daikin's "applications group" and see what they think; a couple
of people over there already know who I am because I've called
in some questions already.
THis guy has probbly found that a lot of the newer 410a equipment he's installing seems ot fail within 5 years. R22 equipment was far less sensitive ot moisture, so you coudl get away with lazy, improper vacuuming and leak test techniques.
I don;t care if its' a 1/2 ton window unit or a 2000 ton chiller. The procedure is virtually the same. You pump it down to a measured micron level, then leak test by either pressurizing it, or seeing if it will hold a vacuum (equipment dependant) then charge the unit by first weighing in the charge, then checking superheat/subcooling.
The only thing that changes, is a 400 Ton centrifugal chiller takes just a little longer ot dehydrate and pump down than a residential 1.5 ton condenser. Like sometimes days to get a full vaccum on a large chiller and get all the moisture out.
Yes 410A is a horrible knee jerk response to environmental mandate.
Its stupid wrapped in dumb as* and the full consequences of phasing out R22 and replacing it with puron crap havent begun yet
As for the OPs concern yes it was a bit sloppy and quick. NEVER use refrigerant alone to test for leaks. Nitrogen is so much cheaper anf it helps dry out the line set and evaporater.
Is it effective to throw in questions on a slightly different issue
onto an older thread? After playing with the system for a few
days now, I've found that the blower *always* runs when the
system is on, which is annoying and in cooling mode, flat-out
dumb because if room temp falls under setpoint [which it could
for any number of reasons, night comes, a cold front blows in]
then all that nice water loaded up on the coil and the drain tray
gets blown right back into the house.
Daikin hints that there's a field setting to fix this, which is in none
of the manuals. I found more info kicking around the net but we
know how reliable *that* can be and it seems like by giving the
consumer no clear options on when the fan runs, they're doing their
customers a massive and possibly mold-inducing disservice.
If a Daikin pro has dealt with this and wants to offer some sage
wisdom, I'm all ears. I don't think "call a pro" is the right answer
here because my contractor doesn't seem like the kind of guy who's
willing to dig into a few system settings.
Sorry, was away over a long weekend...
Outdoor unit is RZQ18PVJU9 inverter type,
indoor is FTQ18PAVJU upright ducted air handler,
remote-controller is BRC1E71 "Navigation" panel.
AHU will have a HKR03 three-kw heater added once
the supplier manages to get it shipped.
I've been back and forth with Daikin applications
engineering and they've given me a few more
field-setting charts including the ones to turn the
fan off outside of setpoint. Strange that it's not
documented, let alone being the default behavior.
Daikin is being quite helpful on this, and of course
their stuff is changing all the time so someone whose
training is a year or two old might not be aware of
some newer tweaks one can do.
I'm still wondering if by-the-book vs. real-life
git-'er-done startup procedures is like the difference
between a full stop at the stop or gently rolling
through when it's judged safe. I don't want to think
that non-thorough practice on an R410A system is
going to mean major work five years down the road.