UPS for A/C unit.

[spark master]

Server room, with about 5 servers. They have a duct-less Sanyo wall mounted A/C unit. One of those mini split systems. It's hard wired, 120volt, 20a breaker. The invertor driven unit is on the roof, and the evaporator is wall mounted in the server room. The power goes from the panel to the roof. Then the power goes from the roof unit, to the indoor unit, with the freon line set.

When ever there is a power surge, or minor power drop out. The A/C unit shuts off, because the electronic controls need to be reset. Then the server room overheats, and they have massive computer problems.

Is there a hard wired UPS (uninteruptable power supply), that I can mount under the roof. that would be capable of handling a 20 amp A/C unit ? Kind of like a massive APC unit, that I have under my desk.

 

[__dan]

Server room, with about 5 servers. They have a duct-less Sanyo wall mounted A/C unit. One of those mini split systems. It's hard wired, 120volt, 20a breaker. The invertor driven unit is on the roof, and the evaporator is wall mounted in the server room. The power goes from the panel to the roof. Then the power goes from the roof unit, to the indoor unit, with the freon line set.

When ever there is a power surge, or minor power drop out. The A/C unit shuts off, because the electronic controls need to be reset. Then the server room overheats, and they have massive computer problems.

Is there a hard wired UPS (uninteruptable power supply), that I can mount under the roof. that would be capable of handling a 20 amp A/C unit ? Kind of like a massive APC unit, that I have under my desk.

If you had a simple control control circuit for the compressor, a relay and motor, I would have looked at putting just the controls on the UPS, with voltage monitoring and an on delay timer for the compressor relay, if approved for change by the manufacturer.

If the inverter powers the compressor, variable speed compressor, the control circuit may not be accessible to intercept and refeed on the UPS. The drive manufacturer may be using the outage with manual reset as a safety, protective limit, device.

My first step would be to contact the manufacturer, see if they offer an auto restart scenario for the controls. Auto restart may be a programmable feature. Check to see if they have two terminals on one of their control boards that you can close to reset/restart. If so you could monitor voltage, current sensing, or temp rise, alarm and trial close to restart the A/C, with an on delay.

I would exhaust the easy solutions first before thinking about putting the compressor on a UPS. A new A/C unit that auto restarts could be cheaper than a right sized UPS, could be cheaper over the long term after factoring in the extra heat and maintenance costs.

 

[broadgage]

Agree, look for other options such as auto re-start before the very considerable expense of putting A/C on a UPS.

You will need a massive UPS.

Another option might be to duplicate the A/C. Set one unit to a higher temperature than the other, such that normally only one unit runs.
If the running unit trips due to a power glitch, then when the room temperature rises the second unit will start. This scheme has the merit of protecting against failure of the A/C unit as well as against power qaulity problems.

 

[Open Neutral]

I went through this. Hopefully, deep inside the unit is a set of contacts that you can close to restart the unit. It will likely take correspondence with the manufacturer to ascertain this.

This is something to look for when spec'ing any future unit.

 

[spark master]

Problem Solved. went back, asked for the package of instructions that came with the A/C unit. Sat outside for a good hour reading the instructions, 3 times. Very sophiscated unit. The remote control, yes, a hand held remote control, that looks like a TV remote control..... communicates with the indoor unit every 5 minutes. It's totally remoted controlled. This remote control must remain within a certain distance of the indoor unit.

When a power failure occurs, the remote still operations on battery; and every 5 minutes the remote sends out a signal. So when the power comes back on,... eventually (within 5 minutes), the remote will throw a signal, and the unit will come back on.

So therefore, the remote MUST have good batteries. Must be mounted and pointed towards the indoor unit. Otherwise it'll work fine.... until a power failure.