airefresco
18-09-2007, 12:16 PM
Got called out on Friday to a Tango cassette system, which runs for 7 minutes and then slows the fan into a super low speed (irrespective of what the fan speed is set for on the controller) for a further two minutes and then goes into fault. There was not a service valve on the suction side at the outdoor unit so I couldnīt take a reading there. Checked and cleaned the filters. At first i suspected a possible fault with the fan, because when it slowed right down the suction line would start to freeze back to the compressor and then the unit would trip.
I wired the fan so it ran in high speed all the time, just to check it was nothing to do with that, and the unit still went in fault after 9 minutes. Although the freezeing didnīt happen.
Went back again yesterday and brazed a 1/4 stub on the suction side. So now i know the gas charge is right and theres nothing wrong there. Disconnect the compressor and ran the unit. Exact same fault occured. Started looking back to the indoor unit. With the compressor disconnected, I disconnected the indoor fan, just to make sure it wasnīt that, still the same fault. Disconnected the drain sensor and the unit tripped straight away. I took the drain pump and sensor out, (which wasnīt easy) and the drain sensor is a design I havenīt seen before. It looks like a coil sensor, but has 4 wires coming out of it (2 black, 2 brown). Across the two of the wires I had 80ohms and open circuit between all the other wires. I put the sensor in some water at various different levels and the result were exact to when the sensor was dry. Tried warming the sensor the up and cooling it down and again, no change in the readings. So i reconnect the sensor and left it hanging in mid air and disconnected the drain pump. Started the unit up and theres 240v to the drain pump.
I think itīs a faulty drain level sensor and the pump is continually running for 9 seven minutes, which causes the unit to go into fault. The thing is, I donīt think Iīm going to be able to get a new sensor for it. I think the best thing would be to just rip out the old internal pump and fit a aspen or something, but i need to know how the old sensor works before I can do that. If unplug the sensor the unit goes straight into fault.
I donīt believe itīs possible to get fault codes from the indoor unit with these units, but maybe someone can prove me wrong here? You can get faults from the outdoor unit, but that doesnīt show a fault, so I think thats only for faults on the outdoor unit. If i knew how the sensor worked, i could make something to fool the indoor unit into thinking the drip tray was empty and use a external pump to get rid of the condensate water.
I would be most grateful if anybody could help me with the sensor issue or spot something that i might have missed.
The model of the in indoor unit is Tango, KFR-112Q/A (theres a second number on the data plate also, KFR-112QW/SA). Gas is R22.
Many thanks
Paul.
I wired the fan so it ran in high speed all the time, just to check it was nothing to do with that, and the unit still went in fault after 9 minutes. Although the freezeing didnīt happen.
Went back again yesterday and brazed a 1/4 stub on the suction side. So now i know the gas charge is right and theres nothing wrong there. Disconnect the compressor and ran the unit. Exact same fault occured. Started looking back to the indoor unit. With the compressor disconnected, I disconnected the indoor fan, just to make sure it wasnīt that, still the same fault. Disconnected the drain sensor and the unit tripped straight away. I took the drain pump and sensor out, (which wasnīt easy) and the drain sensor is a design I havenīt seen before. It looks like a coil sensor, but has 4 wires coming out of it (2 black, 2 brown). Across the two of the wires I had 80ohms and open circuit between all the other wires. I put the sensor in some water at various different levels and the result were exact to when the sensor was dry. Tried warming the sensor the up and cooling it down and again, no change in the readings. So i reconnect the sensor and left it hanging in mid air and disconnected the drain pump. Started the unit up and theres 240v to the drain pump.
I think itīs a faulty drain level sensor and the pump is continually running for 9 seven minutes, which causes the unit to go into fault. The thing is, I donīt think Iīm going to be able to get a new sensor for it. I think the best thing would be to just rip out the old internal pump and fit a aspen or something, but i need to know how the old sensor works before I can do that. If unplug the sensor the unit goes straight into fault.
I donīt believe itīs possible to get fault codes from the indoor unit with these units, but maybe someone can prove me wrong here? You can get faults from the outdoor unit, but that doesnīt show a fault, so I think thats only for faults on the outdoor unit. If i knew how the sensor worked, i could make something to fool the indoor unit into thinking the drip tray was empty and use a external pump to get rid of the condensate water.
I would be most grateful if anybody could help me with the sensor issue or spot something that i might have missed.
The model of the in indoor unit is Tango, KFR-112Q/A (theres a second number on the data plate also, KFR-112QW/SA). Gas is R22.
Many thanks
Paul.