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Old 07-26-15, 10:49 AM   #5
Apprentice EcoRenovator
Join Date: May 2011
Location: Tortosa, Spain
Posts: 218
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Glad you like the mod...

The original unit was a fairly generic, probably badge engineered Chinese unit. The actual name/model was a Rainbow Electronics JS3210AH, 12000btu, R22 refrigerant and the indoor unit has an air capacity of 530M3 per hour.

I would imagine that almost any of these mini splits could be modified to work as a fan-coil. Most have little or any connection with the operating conditions of the external unit, at most they may have a wire that goes to a sensor on the evaporator, in the case of this machine it didn't even have that. Most just have power feeds to the compressor, fan and 4-way valve so they should work happily when disconnected from the outdoor unit.

The challenge is more a mechanical one than anything else, you need to make sure the bundle of pipes doesn't foul the existing electronics or motors as normally there are only 2 pipes leaving the unit. In this case I was fortunate as there was quite a bit of space.

You also need to know how to braze. Grouping the 6 x 1/4" tubes together wasn't too bad - I did slightly flange the 18mm reducer and slightly crushed the 1/4" tubes and that made it easier to insert them. To flange it out I used a narrow socket from a socket set and hammered it into the fitting, the shoulder on the fitting created the flange.

Brazing the tubes and sealing the pipe took a couple of attempts (hence the overheated case!). I checked it was all sealed by pressurising it with nitrogen.

At the moment the unit is hanging on my boiler room wall ad the cold feed isn't that cold but it was sufficient to do some basic proof of concept tests.

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