P-266 Fan Speed Control
I was just wondering if anybody has had problems with the J/C P-266 fan speed controls. I have a customer that has six new Koolant Koolers chillers with P-266 controls on the remote condensers. They are only around two years old and two of the P-266's have been replaced. I found another one today that isn't working. The fan runs at full voltage & speed with a call for cooling. They don't seem very reliable for the cost.
The place I work uses these for all single phase condenser fan motors. If they running at full speed I would expect to have had a transducer failure rather then a failure of the p-266. If you unhook the pressure transducer it will run at full, and thus if the transducer is not working the fan will run at full. You can test one of these via hooking a 0-10vdc supply to c and p and modulating between 0 and 5 volts. I would also confirm that the programming is set up correctly.
Most of the times I have seen these fail the p-266 will not send any voltage to the fan at all.
Mind you I am working with brand new controllers in a factory setting. I have not heard of any massive warranty issues with them though. We have shipped them for the last 4-5 years.
I was also thinking it could just be the transducer. When one of the other chillers had a problem, the P-266 wasn't putting out any voltage to the fan motor. At that time I purchased both the P-266 and the transducer. It is very hard to get a shutdown for these process chillers and the parts were not in stock anywhere I called. So I ordered and replaced both when I had the chiller down. I didn't have a long enough window to do much testing.
Well if you can get access to it while the system is running you could just disconnect the p terminal and see if the transducer is supplying any voltage at all. Should also check the v and c terminals on the controller to make sure its supply 5v out. I think it's 5v. I don't know if the controller is accessible during operation on your equipment or not.
I checked it again the other day and had 5 vdc between terminals v & c, 2.8 vdc between terminals p & v and nothing between p & c. I ordered a new control and tranducer and installed them today. I just replaced the tranducer to start with and had the same condition, the fan ran at full speed. Changed out the P-266 control and that fixed the problem. I checked voltage again and had 2.5 vdc between terminals p & v and p & c.
Originally Posted by Elfshadow