how to force an inverter driven A/C split unit to cool deeper

[staf]

Hi I'd wonder if somebody could help me with the following. On a A/C split unit with a Sanyo inverter rotary compressor (type C-6RZ110H1A) I want to be able to cool the room down to 12°C but I'am limited to 16°C on the remote control. It's for a wine storage... Since on/off units are prohibited in the EU as of Jan. 1st., 2013 we need to buy/install inverter units and inverter units are not autorized to cool lower than 16°C (EU legislation lot.10). Is the inverter signal sent to the compressor a 4-20mA of 0-10V signal? Regards, Staf

[Tayters]

It's controlled through the communications wire between indoor and outdoor then the outdoor unit PCB will control inverter module whilst monitoring for any discrepancies in the feedback circuit - good luckj!

Simpler to fool indoor air probe to give an incorrect reading perhaps. Haven't tried it myself but recall reading about it on here somewhere.

Cheers,
Andy.

[Tayters]

This is what I was thinking of

http://www.refrigeration-engineer.com/forums/showthread.php?36055-Retrofittable-air-conditioner-to-refrigeration-conversion-unit&highlight=wine

Cheeky conversion by Mr Bartlett but a fixed speed unit I guess looking at the controller, could be wrong though

Failing that get a cellar cooler!

[install monkey]

find out the resistance of the air sensor in the controller- and stick a say 4k ohm resister to offset the temp by 4 deg, but the system must be well over sized otherwise its gonna freeze up- typically fins are spaced furthur apart and the fan velocity is increased too

[staf]

hmm thanks everybody but I was hoping to read what kind of signal is send to the compressor to control its speed and how I could affect that speed... probably this would create other problems.... oww dear, what am I missing the simple on/off units!

[spannerspinner]

Hi,
Was just randomly browsing here and found an interesting comment regarding off setting the sensor using a resistor in series? Is it fair to say 1 k ohm resistor will offset 1 degree ??

[install monkey]

if you get a table of resistances chart for the sensor- then most are around 10-2000 ohm so a 1k ohm resistor will off set it by about 0.5-1 deg- the chart will show you more accuratly, this is based on being ptc type- positive temperature co efficient
ntc will have a reverse affect

[The Viking]

OK,
Let me be the stupid person to ask the obvious question...

Why not use a cellar cooler designed to run at those temperatures in the first place???

:cool: