Sanyo 24KHS72 AC/HP DIY install project

[Xringer]

I 'think' the problem might be with the indoor unit's firmware..
I'm not sure, but I suspect the controller might 'think' it's talking to a 36,000 BTU (or larger?), and not a 24,000 BTU..
Otherwise, why would it just zoom up to over 3.5kW in a matter of 20-30 seconds. IF, you demand a big temperature change..

My guess: I'm running my 24,000 BTUs of cooling at about 6,000 to 18,000 BTUs.
It might not have the same weak point (at the sensor above the compressor)
but it's Copper, and R410a is High pressure stuff (compared to regular old refrigerant).
When we got this new unit, I did a controlled test,
and I KNOW that High Power mode will take it all the way to a over-load / over-pressure reset.
On the old unit, those resets happened a few times, with no problems. But,
it wasn't able to protect itself last time, so I'm not going to risk it anymore. I'll protect it. Manually.

That means, if we come in an the house is 86, we set the Sanyo for 84,
wait a while. The fan will slow way down. (At 450-480watts).
Then we set downwards another 2 degrees. It takes paying attention,
but it's not a long process, unless the house is way over-heated.

Once the room temp is locked in, it just stays there. And the power used
just drops off to 430 to 800w, depending on the outside temps.
Most of the time, the power usage is low.. July tells the tale..

This thing uses power like my Plasma TV.. Not a lot..

~~~

I did see those pre-charged line sets, when I was shopping.
It wasn't a name I've seen before and it was extra costly.

I'm not sold on O-rings. I've see what CO2 can do to O-rings..

I also read install manuals where there was no pressure testing or vacuum pulled.
They just hooked it up, let some refrigerant pressure into the lineset, closed it, then soap-bubbled it.

To fill the lineset, they cracked the valve again, loosened a flare nut to let out some
mixed gas (hoping to get all the air flushed) and then tightened it down.
It might work, but there are a few questions there..
It just seemed too much like a hack job.. But, in poorer parts of the world,
the still need AC.. And don't have a lot of money to spend on installs..?.

[nw_guy]

It *could* be a firmware glitch but I suspect Sanyo knows what they're doing and perhaps the over limit trips on your first unit were an anomaly? Just a thought, but you might want to put your manifold gauge on and compare the pressure readings in heating mode (perhaps wait until this fall) with those in the service manual? That should tell if it's really stressing itself or if it's working normally?

And perhaps your unit behaves differently, but with mine, if the fan is not set to Auto, and is set to the low or medium speeds, it will *never* run the compressor at full tilt even if the set point is far from the room temp. If yours behaves the same way, that seems like the easy solution? Just never set the fan on high or auto?

For those interested, my 9000 BUT unit cooling runs about 2.5 amps at 120 volts in quiet mode. With power factor correction, that's well under 300 watts which is fairly amazing consider it still cools a fairly large space and is literally nearly silent while doing so. On the low fan speed it's about 3.5 amps, medium is about 4.2 amps and high is 5.5 amps. It's rated at 16 SEER.

I haven't yet run it in heating mode as it's been mild to warm weather here. But hopefully it will be similarly impressive while providing heat.

Again, for those interested, you could easily run my 9000 BTU unit on a relatively modest solar array off grid--especially at the lower fan settings.

[Xringer]

Do you have this one? 09KHS71 - Sanyo 9,000 BTU

I've been thinking about one of these for my daughter's house.


Anyways, when we replaced the outdoor unit, I did a short test and saw
the power increasing to a point where it was getting close to Overload/ Resetting,
so I stopped it. Turned it back closer to room temp.

So, that's why I think there may be a bug in the indoor unit's controller board.

I can't recall right now, but there is a reason that I've been using Auto mode for the fan..
Maybe it's because it slows down to a really low speed a lot and is so quiet.?.


But, you have me curious, so I will try setting the fan to Low and crank down the temp setting.
If it gets up to 2+ KW, I'll back it off..

However, Low is a lot louder than Auto is most of the time..

Wow it worked, It's 74 in here and I used Low-Fan and set for 68F.
The power never got up higher than 980 watts!

When I set the temp back to 74, the outdoor gear went quiet
and the power dropped off to 60 watts.

BUT, the indoor Low-Fan stays on Low! Which makes a lot more noise than
Auto (which uses Quiet mode much of the time).

It's now using 360w in Low-Fan or in Low-Fan + Quiet mode..
I seem to recall there were times when Quiet mode used more power
than Auto mode..

Now in in Low-Fan + Quiet mode:
It just reached set-point and is now cycling down to 60w for a while and
then moving back up to higher power. It's moving a lot in the area of 440 to 730w.
But on average, it's staying in the mid 400s.

One of the things I seem to remember about Quiet mode is the indoor coil seems to get much colder.
I guess to make up for the slow moving fan.. That might be a reason it uses more power.?.

It's night here and the outdoor temp is about 76. (But very humid).
With the Sanyo set for 74, it seems like Quiet mode is costing more to run.

I'm testing in Auto-Fan now and the power use seems to be stuck at 380w.?.

Anyways, the idea that seems to have stuck, is that Auto-fan mode more closely matched the indoor fan to the actions of the outdoor motors, using less power per BTU.. The indoor coil doesn't have to get extra cold
because of low air flow, when Auto can adjust the indoor fan to kinda match the temperature of the R410A..


It seems Auto-Fan is king right now. And Low-Fan is what should be used
when powering-up for a big cool-down task..
Staying under 1kW is sweet!!

It going to be hot tomorrow afternoon, I get some more meaningful testing done then.

In the winter, I think using Low-Fan for large changes (like the morning 66 to 72) will be easier on the power use, but will slow down the speed of the warm-up..
I don't think it's going to extend the warm-up cycle enough to worry about.
I'll just stay in bed for an extra nap..

[Xringer]

It worked again!
We left the Sanyo on 78 when we left this morning.
Came back this afternoon (91 outdoors) and wanted to get cool a bit faster..

Set the indoor fan on Low and the setpoint at 72. Within 30-40 seconds, the power had
stepped up to 1kW and slowly peaked out at 1.6kW before dropping down to a range
of 800W to 1.2kW.

It just hit 76 degs in here, so I set the Fan to medium speed. More cold air than before,
and the power use dropped off from 900w to 680w..

Uh oh.. Just for kicks, I set it for 70d (medium speed) and it worked it's way up to 1.7kW.
So, with medium speed, I'll still have to be careful of how many degrees of change we ask for.
Low speed seems to be the safest way to go..

[nw_guy]

Originally Posted by Xringer

Do you have this one?

09KHS71 - Sanyo 9,000 BTU

I've been thinking about one of these for my daughter's house.

<snip>

But, you have me curious, so I will try setting the fan to Low and crank down the temp setting.
If it gets up to 2+ KW, I'll back it off..

However, Low is a lot louder than Auto is most of the time..

Wow it worked, It's 74 in here and I used Low-Fan and set for 68F.
The power never got up higher than 980 watts!

When I set the temp back to 74, the outdoor gear went quiet
and the power dropped off to 60 watts.

BUT, the indoor Low-Fan stays on Low! Which makes a lot more noise than
Auto (which uses Quiet mode much of the time).

It's now using 360w in Low-Fan or in Low-Fan + Quiet mode..
I seem to recall there were times when Quiet mode used more power
than Auto mode.

Glad it worked. And yes, I have the KHS0971 and I'm really happy with it. As I mentioned earlier, the 12,000 BTU (1 ton) next model up uses the same indoor unit, the same compressor and size outdoor unit. It simply has a bigger coil in the outdoor unit and runs the fans and compressor faster in high. I opted for the smallest one as I'm running mine on a shared 15 amp 120V circuit and wanted the lowest power consumption possible.

I think for a given indoor fan speed the overall efficiency is the same regardless if you manually set the fan or use Auto. It is true, as we discussed earlier, that higher fan speeds are more efficient overall (BTU per watt). So, because Auto sometimes uses higher fan speeds, it is somewhat more efficient at the expense of noise but only when its using the higher speeds.

If you want to get the most BTU's per $ I'd suggest using the Medium fan speed when you need more cooling/heating. That should still keep your peak power down but give you the most efficient operation.

And yes, Auto lets the unit get to the desired set point faster when its either been off or you change the set point. But, you've been deliberately slowing that process down anyway. Again, Medium fan should accomplish the same thing.

I tried mine in heating mode for the first time and it varies the fan speed somewhat even with the fan set to Low or Quiet (which it does not do when cooling). So there's still some "auto" action going on in heat mode.

One other advantage of split systems I forgot to point out to others: At least on the better ones, the room temp sensor is in the remote. That means it's reading the true room temp not the temp near the very hot or cold coil. With window air conditioners/heatpumps the sensor is in the unit itself and hence grossly inaccurate. Typically the compressor cycles on window units even when it should just stay off wasting energy and shortening the life of the unit.

Anyway, I'll say it again. A high quality inverter split system is such a huge improvement over window mount units, and they work so well, I just don't understand why they're not more popular in the USA. Perhaps with the tax credits and higher energy costs more people will now consider them?

[Xringer]

Setting it for Low speed, seems to get the job done pretty fast.
Remember, this is 24k cooling and 36k heating. And a bit over-sized for mild weather.
Medium got it up to 1.7kw.. A bit more than I like.

So, I'm going to try using Low for a while and switch to Auto once the house is at the requested temp.

One thing I really like about auto is the low noise during idle times.
Whereas the manual modes 'Low' speed, leaves the fan cranking all the time.
(At least while I've been in the living room).
In auto, the fan can get down to just a few RPMs. Hardly moving any air at all.
I think the only reason it still turns at all, is just-in-case you have enabled the built-in temp sensor (in the wall unit).

When it's not so hot out, when the R410a isn't being pumped, I don't need to hear the fan running..
I know it's not much wattage at all, but the noise of the indoor fan is still there.
It's not much noise, and the filter is cleaning the air, but that steady drone bugs me.

I guess the quiet times using Auto has spoiled me..

Oh yeah, just a few feet under the indoor unit, is where I like to sit and watch my little LCDTV..
And, I'm a little hard-of-hearing..

In time, these units will become more popular in the USA. People who have them, love them.

I don't think many installers like them at all. Too quick and easy to install.
No way they can send the kid to Harvard if they are installing these in half a day.

Cheers,
Rich

[Xringer]

Total Sanyo power use since 3/26/10:

Month/kWh

3 , 55
4 , 110
5 , 64
6 , 60
7 , 116
8 , 60
9 , 25.9
10, 94.6
11, 117

Total kWh 703 or about $147


Here's the day-by-day data:
Weather Station History : Weather Underground (Charts & daily data)

July was brutal, but August was too. So why the lower kWhs in August?
In July, we were using 72-74 setting and in August, we were more acclimatised and started using 74-76 settings!!

Next summer, I will have to remember what a big difference a slight change can make in the bill..
Just hope I can remember to read these notes!!

Cheers,
Rich

[Daox]

Wow, that is a huge difference for a few degrees. I'm guessing you hit some sort of efficiency wall at that point?

[Xringer]

Originally Posted by Daox

Wow, that is a huge difference for a few degrees. I'm guessing you hit some sort of efficiency wall at that point?

After posting, I looked closer and August was actually a littler cooler than July.
On average, it was about 2 dF cooler. (It didn't seem like it at the time).
Maybe being cooler at night lowered the August average.?.

So, it was likely two factors combined, that lowered the August number.
We were used to hotter weather and it wasn't as hot..

[st2288]

Thanks for such a great post. I am in the process of installing 2 Split unit in my house.
I search high and low on what is the best way to bend the line set, especially the one coming out for the condenser, since you can't slip an external spring bender . They don't sell the internal one here in the state. I thought I will a heavy gauge line power cord inside and bend. I think that should work. I thought of using a regular bender, but the radius is too big.. any thought?

Thanks