Sanyo 24KHS72 AC/HP DIY install project

[MN Renovator]

Originally Posted by AC_Hacker

st2288,

I didn't catch it if you are using a mini-split or a whole-house heat pump.

But I'm using a 9,000 BTU Sanyo mini-split, and it has continued to work just fine down to 12 F. As I recall, the sales literature for mine said that this unit was good down to 17 F, but obviously it'll do better than that.

I have noticed that the COP drops when the outside temp goes way down, but it's still superior to resistance heat.

I've noticed that according to the sales lit, the new 9RL and 12RL Fujitsus are good down to 5 F.

-AC_Hacker

Fujitsu makes HPSF 10 SEER 18 22k BTU(36,200k max heat and 17,800 at 17 F) and 30k BTU(37,500k max heat and 20,200 at 17 F) units that are new this year and rated to operate down to 0 F. To me 5 degrees is small and the extra capacity isn't needed as I'm aiming to cut A/C costs versus natural gas bills and would rather aim for the efficiency of the 12RLS unit even though it may be undersized but it has an economy mode with holds it at 70% which I think might be the 12k nominal cooling and then I would be able to close off part of the upstairs to enclose the unit a bit more for comfort as conditions get more unbearable or fire up the 1986 energy sucking central air if I really need to supplement it for a short period.

[Xringer]

I'm trying to provide some better over-load/over-pressure protection for the Sanyo.
Adding a (Used Ebay) 10A motor protector type breaker. It's a DIN, which will require a new box.



It's installed temporarily on the outside of the box on the left side.
It's wired in series with the old 15A breaker-pair..

Unfortunately, as I was wiring it in, I noticed a problem. Some hacker
has been tweaking the Amp settings. I could tell, because he broke
part of the head off one of the adjustment screws.
A replacement is on the way now.

Anyways, my theory is a 2.5kW breaker (250v X 10A = 2500 watts)
that trips at 125% is way better than a 15A breaker. (3750W).
Since max input during heating, should be 2490 watts. (Sanyo Spec).

I'll bet that 15A breaker would trip, up around 20A. Or 5kW

So far, the hacked breaker hasn't popped. So, my guess is, it's set real high.
I can picture the service guy in the field. He has a motor that's going bad.
It's drawing over 10A. He is too tired or dumb to replace the motor,
so he adjusts the breaker to max current. (29 amps?)
End of problem. He figures any evidence will be destroyed in the ensuing fire.

Edit: Dec 20, 2010
The replacement DIN 10A breaker came today. It looks brand new.
It's installed and seems didn't pop at 1500w, so it might be okay..

[Xringer]

Got the second power surge of the week this morning about 8AM..
Which, coincided with a higher than normal line voltage.. (about 256 vac).
It was a rerun of an early morning alarm earlier this week..

I'm not sure why it shot up to 2.88kW, (setting off both alarms, waking us up).
But since the house was only about 19C (with the Sanyo set for 21C),
with the outdoor temp just above freezing+80% humidity,

I'm assuming that it had been defrosting for at least an hour.
(The outdoor intake coil was moist but completely ice free. w/Water on the pad)
So, between 5-7AM until 8AM, the house cooled to 19C..
When the Heat mode came back on at 8AM, calling for 21C, the line voltage was high!
Which led to a gradual increase to 2.88kW and me shutting the system down..

20 minutes later, it's running like nothing had happened..

It seems to be an unlucky combination of high line voltage at the end
of a long defrost cycle, (cooled house) and a call for a lot of heat..

[AC_Hacker]

Xringer,

Did you put the jacket on the compressor, or did it come that way?

-AC_Hacker

[Xringer]

It came that way. On the bottom, you can see two white cables connected
into the Crankcase heater element, that encircles the base of the compressor.
When I turn the unit off, that heater stays on, drawing 30-40 watts.. 24-7.

~~~

I was just thinking, a lot of these power surges occur right around sunup..
Maybe I should set the remote timer function to shut down the Sanyo at 4:30 AM.?.

[AC_Hacker]

Originally Posted by Xringer

I was just thinking, a lot of these power surges occur right around sunup..
Maybe I should set the remote timer function to shut down the Sanyo at 4:30 AM.?.

Is there any chance that the circuit that you put in especially for your heat pump is under-wired?

Possibly it is not getting the burst-current it needs to do it's thing?

Higher-capacity wire could be a good thing.

Of course, higher-capacity fusing would be a very bad thing, what with LRA being what they are.

-AC_Hacker

[Xringer]

Under-wired? LOL! I hear that's a problem at airports these days..

No, it's a short run of #12. And if it was resistive (dropping voltage) ,
the Sanyo would likely work better.
One of the first things I did was measure the voltage at the disconnect box,
and checked the whole run (under load)with an IR scanner. It's all to code.

~~~

When the NStar guys were first out here a few weeks ago,
they (for no reason they could explain) decided to change the lines from the pole into my house.
I asked them not to fix what wasn't broke, but they would not listen.

I got a little voltage INCREASE! Exactly the opposite of what I wanted!

Then a week or two later, they came back and changed the short transformer leads to the pole 220 lines..
Why? To give me higher voltage? When I was begging for lower voltage?? LOL!



I was talking to the NStar guy on the phone this morning (after our 128+ overvoltage) and it suddenly occurred to me..

I may be retired, but about 80% of the people on this section of the grid might be shedding a LOT of load..
They are going to work in the morning! Many leave at 8AMish..
No more coffee pots, toasters & etc. Heating systems are setback too...

I'll bet you 5 kWh, that's why we are seeing 8AM voltage peaks..

Hey!
Merry Xmas!!
Rich

[Xringer]

From the user's guide:

•High Power Operation
If not in Auto Operation, the unit operates at
maximum output for 30 minutes, regardless of the desired temperature.
The fan speed is 1 step above “High”.

That got me wondering how 'Auto Operation' mode would work in the dead of winter.?.
It would inhibit High Power operation.. Which is nice..

But, will it do anything to inhibit the normal 'Fast Heat Boost' (installed for impatient Americans)??

So, I'm trying out Auto Mode operation this morning.
So far, it hasn't peaked over 1600w.. I'll keep watching it and report on any problems..

It steps up, but it seems not to be stepping so high.. Maybe it's just the
current inside and outside temps.. Or maybe Auto is a way to moderate
the power step-up routine.. (Which sometimes goes over-board).

I hope it doesn't switch to Cooling when the sun comes in and warms us up..
That might not be possible, if the outdoor thermistor is checked,
to see if Cooling mode is even possible.

[Xringer]

Still using Auto mode, so far it's been working pretty well. At least when the line voltage is normal..
Running Hybrid mode, burning a little oil also.


I saw an interesting Sanyo event last night. The snow was getting real bad,
winds were blowing it all over the place. By the late evening, the outdoor
coil was so covered with snow and ice, the air coming out (using 500w),
was barely warm. But we waited for hours and it never went into Defrost mode!

I stayed up late, watching for the defrost mode to start. It never did.
So, at about 12:30AM, I decided to shut it down and go to bed.
The vent closed, the heat LED went off and the power dropped to 60w..

A normal shut down. I sat in the living room reading for a little while longer,
when I heard a little creaking from the indoor unit.?.
But, it was off.?. I looked at the TED and the power was creeping up!
And it was still off! Within a minute, it was at 800w.

Then, I knew! It was doing a Stealth Defrost! Within minutes,
it hit the top at 1280 watts and stayed there for about 10 minutes.
All the while making gurgling sounds. I scanned the indoor coil
and it was 32F.. But, no fan at all.. It was OFF after all..

So, I was getting the standard defrost, (Standard for Auto Mode)
but without any blinking LEDs.. After a while, it started to cut back
on power and slowly ramped down. Back to sleep..

When I looked out the window this morning, (It's still snowing)
I could see where most of ice and snow had cleared.
Only the bottom edge of the coil still had a little ice pack..

It's 28F outdoors and the Sanyo is working pretty well this morning.
But, I'll be turning it off later.. To see if it's going to do another defrost..


What worries me about running up power use while the unit is OFF,
it's not going to respond to remote commands.
I'll have to turn the unit on, and then turn it down, in case of over-wattage..

I hope it can be done fast enough. And Defrost mode doesn't lock out
the remote from calling for less heat..

[Vern2]

About me:
Hay, I'm a new be! I had a stroke at work, so retired at 59 (telephone man)and now 66, life is great! Walk a little funny and have the use of one arm, so typing is slow. One good thing nothing stops me and I'm still tough as nails. I built my own house, took me 6 years to do it, no help. 2200 square feet. No house payment at 30, after coming back from Vet nam, Buck Sgt.

Wow! Finally got to the last post. It says posted today. A couple days ago it was 2009. I can't believe I found a group of crazy guys like me DIYers. I wish I could feel your pain, I'm in Arizona, sorry. We have the same problem with AC techs. $6,000 install for $1000 of equipment.

Great stuff:
It took so long to go through all the posts, because I was building a database for my install for a very hot shop in the garage.

Thanks:
Love you guys, and especially Xringer, for starting the thread , Wait! Got a wife of over 40 years and two great kids, boy, girl.

I see I can't post pictures or links until I have 5 posts, I have an hour til bed time be I'll fix that.

Vern