Fujitsu AOU24RML1 + (2)ARU12RML multisplit installation

[Xringer]

I think the best benefit of Ductless is the lack of losses.
Sheet metal ducts that starts off at the wrong temperature,
is going to be heated (or cooled) when the air flows.
If the ambient temperature outside the sheet metal ducts are difference than
what's inside the ducts, there will be losses. Insulation of the ducts works,
but the total cost in labor (and parts) makes it undesirable in many cases. (Like retrofits).

[mrd]

Yes, duct losses can waste a dramatic portion of energy spent heating and cooling; I recall reading numbers around 20-30%. It is highly recommended to place all ductwork within the conditioned envelope of your home, then you only need to worry about air distribution. That was a major reason I chose to build a conditioned crawlspace.

[Xringer]

That's a great idea. I wish my basement wasn't such a big geothermal slab..
If I wasn't so close to my expiration date, I would insulate the living daylights out of that dank basement!

On the plus side, it's mighty cool down there on a hot summer day..

[AC_Hacker]

Originally Posted by Xringer

If I wasn't so close to my expiration date...

Do not go gentle into that good night.
Renovate, renovate against the dying of the light.

-AC

[BradC]

Originally Posted by mrd

I have seen a refrigerant diagram for another Fujitsu system that is nearly identical, but it indicates a receiver between the two heat exchangers in the outdoor unit. I'm not sure if there is one in my system or not, I've read the receiver is where the unit stores the refrigerant during pump down/shipping.

The receiver is necessary if the combination of all the evaporators + pipework you can bolt to the system have a greater volume than the condenser, otherwise when you pump down you can just store the refrigerant in the condenser.

<edit>I have no idea how this post wound up tacked to this thread!

[mrd]

Well, it appears I neglected finishing documentation of my installation in this thread.

I did finish the installation, and the rest of the home, and we finally moved in at the beginning of the year. The system has been working flawlessly. I installed a washable electrostatic filter in the larger 20x25 return, and the airflow is still good - so that saves a little on filter costs. I haven't tried one in the 14x20 return, as I'm worried it may be too constrictive for the blower.

The system has kept us warm throughout this winter, though it hasn't been terribly cold this season. I keep the tstats around 72/74. The past two months our electric bill is roughly 38 kWh/day for everything. I don't have a meter to only read the HVAC electric consumption. I suspect the electric resistance water heater is a big chunk of that usage. All appliances are electric.

[Xringer]

If you are interested in monitoring just your HP, you might want to try a TED.

The probes on my TED are currently measuring the power used by both my Sanyos.
If you aren't interested in keeping computer files of your power use, the less
expensive models (TED Model 1001) should work okay.
I got the link+software and don't use it much. The TED saves monthly data for at least a year.
It's easy to scroll the data and write it down, by hand..

Which TED works for you?

The winter has been mild here also. The two Sanyos have used $90 to $100 a month when it was pretty cold.
(@ $0.1661 per kWh).

[mrd]

That's funny, the TED logo is almost identical to that of TED: Ideas worth spreading

[Vern2]

TED

I had know experience in the building trade, but built my home. My Build

Vern

[Vern2]

Originally Posted by Xringer

I found the nitrogen test pretty easy, since I already had a paint-ball air tank.
They are cheap and come with a 800-900 PSI regulator built in.
Hooking one up to your manifold isn't much of a problem..

But, there is a work-around, that's fairly common in these kinds of installations.

After you have done your vacuum testing, and everything looks good,
and you are at the 'release the 410a' step. Stop right there.

Read over your manual, it might even tell you how to do this pressure test.
You release 410a into the line-set for 10 or 15 seconds, and then shut off the valve.
If there is a loose fitting, you won't suffer a big loss of refrigerant.
Now is the time to check all your flare fittings with soapy water.
You might also have a stethoscope handy to 'listen' to the fittings.
I use one from an old BP tester. Just removed the big disc on the end of the hose.

Or, you can just use 3' of flexible tubing, holding one end to your ear and the other near the fittings.
That worked very well for me, when I was on the phone with Sanyo,
I was able to 'pipe' the hissing sound to the phone. Making my case for a leak right above the compressor.

Anyways, when you don't detect any leaks, then you can release the 410a for real.

I did this 401a pressure test with my Sanyo (both times I installed) and it
gave me confidence in the flares.

I guess you could do this test with a manifold attached and just watch the pressure for a couple of days..
Since my line-set was pre-flared and was so simple (4 connections),
I tried to keep it simple and not have to waste any 410a in the hoses.

Xringer,

I too have 12 oz paint ball bottles for welding. I picked then up at a sporting goods store, the store even refills them for me, by weight not pressure. Can you explain a little more... Paint bottles come with CO2, but you talk about using nitrogen. Can you link to the adapters or pressure regulator you used to pressurize system, when Co2 bottles have a pressure of 900 psi. What gas did you use and how did you regulate the pressure? My bottles have needle valves and no regulator.

Vern