Daikin 1.5HP Cooling Only Non-Inverter (model FTD35F) compressor on/off

Hi everyone, this post is related to the thread:

refrigeration-engineer.com/forums/showthread.php?t=10925

Thankyou to everyone who provided some help in the last thread. The a/c was installed yesterday, along with the Daikin Wiring Adaptor for Stop/Start Interface (model KRP413A1S).

Everything works as I expected, the KRP starts and stops the inside unit as exepcted, and I am very very happy from that perspective.

Of course now I face others hurdles. :)

The inside unit is mounted at the top of a stairwell that leads down into a cellar, which is about 4m down. I have the vertical vent positioned completely downwards (as far as it will go). and the horizinal vent away from the closest wall it was positioned next to as suggested in the user manual.

The cellar is very well insulated, and is completely sealed apart from an exhaust fan at the top of the stairwell and a fresh air vent in the bottom of the cellar. Even the door is sealed.

For now I have had the a/c working at full capacity, to bascially see what it is capable of, I have managed to bring the core cellar temperature down about 4-5 degreesC (19degC in the cellar). Good news is it has had little impact on humidity which is stable between 70-75%.

I have measured the air coming out of the indoor unit directly at 13degC so its certainly delivering nice cool air. I have a few questions?

1. How can I get more of that cooler air down into the cellar? Perhaps the vents need to be pointed in a different direction? I would have thought the cold air would drop into the abyss of the cellar.

2. How can I keep the compressor running for longer without it cutting out when the temperature in the stairwell hits 18degC (the setting on the remote)? The temperature in the stairwell is about 2-3DegC cooler than in the guts of the cellar, so the compressor on the a/c stops long before I need it to. Is there anything I can do to trick the indoor unit it is warmer ? Can I insulate the thyristor in the unit ? Cover up the holes at the front of the unit for the temperature sensor? Is there a way to stop the compressor turning on/off like this ?

Any advice would be appreicated.

I also have the manual for the KRP413A1S, so if anybody does need it, just PM me, I'll happily forward it on.

Does a KRCS01 Remote Sensor override the indoor unit sensor that controller the compressor?

If so, perhaps installing one of these and placing it in a "warmer" location will prevent the compressor from turning off.

Any suggestions?

Your exhaust fan is where the evap is, and you're bringing in warm air from ouside at the opposite end of the celler?
Congratulations, you put the a/c in the worst possible spot.
Making the thing run longer will just ice up the coil. Splits aren't designed to go below 21C at the unit inlet for long periods of time. edit: 20C = 0C evap temp = icing up
small units like you have have piddly fans that don't move much air, where you mount it is really important. They might blow some air out, but they are sucking air in from the same area as well.

Well thanks for that mate. The fan does not run all the time, it runs for 30 minutes at 6 in the morning to recirculate some air, I find it doesn't alter the temp at all, but it good for humidity.

It wasn't possible to mount the head unit inside the cellar, its underground.

It's possible to mount the indoor on any flat wall, you just run the pipes along the inside wall, then up and out with a condensate pump for the drain at the same place the pipes exit the cellar now.
It's a cellar, it doesn't have to look pretty, and if running insulated pipes around the cellar looked bad, you could cover it in pipe ducting,
The exhaust fan may not be running all the time, but outside air can get in at those points even without the fan running.

Just covered the fan hole up, process of elimination.

ummm no way im having ugly pipework in my cellar.

I fully covered the fan hole up and disabled it. I used a flow meter, i did measure 0.5 m/s air flow going through the fan at about 28 degrees, so no doubt that had an effect.

It's an air conditioner, function is more important than form if you're doing it on the cheap, (which you are by using a wall split to cool a cellar).
You really should have had a professional look at what you were planning before you did anything.
We do heaps of cellars, yes you can use an air con, but not a wall split. We use commercial grade gear with humidifiers that stand the test of time and can repair same day. Not proprietry import splits that you have to wait days for parts to be delivered from sydney or overseas. We do some pretty large collections.

Anyway, you aren't using the right equipment in the first place, as mentioned in your last thread. And now you are at another disadvantage by putting it where it's wouldn't work very well and you expect lower than 21C temperatures.

Also something else is wrong there, you say cellar temp 19C, air con evap off temp 13C.
Getting a 6K differential isn't very good, you should get at least 10K differential from a wall split, I aim for 12K when testing them, 15K isn't unusual.
Then again maybe that's why your humidity hasn't suffered, because the a/c isn't running as good as it should. I gues you're going to have to live with poor cooling, or fix that and get low humidity.
Anyway, that's me done, whether you take my advice or not I'm sure you'll find a way to make it work to your ideas.

As I remember it, my first reply to your previous thread was:

Quote:

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Originally Posted by The Viking

Here comes the bad bit. (assuming that you like to drink your wine)

The Daikin unit is designed to provide comfort cooling.
(No big deal?)

First of all it is designed to keep a temperature of about 21-22 Degrees C, far too warm for your wine (which ideally would be stored around 15 degrees C).

Secondly, and more important, in order to keep humans comfortable you keep the moisture levels low. As a result, units designed for comfort cooling removes a lot of moisture (compared to refrigeration units). Your wine should ideally be stored in humidity above 70%, there is no way a comfort cooling unit will leave that much moisture in the room and still maintain the temperature.

What you need is a cellar cooler (which due to different design doesn't dehumidify as much as an air conditioner). Possibly together with a humidifier.


Good luck.

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So, sorry to say it, but sometimes. just sometimes, I do know what I'm talking about.....

I can't remember which model remote controller that you have but with most Daikin split controllers you can select whether the unit is controlled by a sensor in the unit or within the remote controller.

If you have this option then perhaps you could move the controller down into the cellar, only a small cable on show.

The core cellar temperature is currently at 18.5degC (and were having a spell of rather hot days), it drops to 16degC in winter, hence I'm achieving a 2.5degC temperature differential throughout the year. So it is achieving less than 21degC. Humidity is constant at around 70-75%.

I don't intend on keeping anything longer than 10 - 15 years in the cellar, so the result is ideal.

Brian, the model number of my remote control is ARC433A55.

The ARC, that's an infra red one, isn't it?
So no option to use the remote's sensor, sorry.

What you might get away with doing if you are electronically minded, is to relocate the the sensor in the unit. It is possible (but bad practice) to cut the sensor lead and extend it. this would allow you to fit the sensor externally to the unit.

But, be aware, you are opening a whole can of worms with all types of problems entering the arena.

I have spoken to a local a/c mechanic who modifies the temperature sensor circuit to trick the indoor unit its a few degrees warmer than what it really is, perhaps this is an option.