View Full Version : McQuay RPS045
I have a McQuay RPS045CSY (Micro tech II) that is having a problem with the condensor fan motors not coming on. The compressors run but the board will not bring on the motors ( both circuits are doing the same thing) another company replaced the relay boards for the compressors and fans and one communication board. This did not solve the problem, I think the problem is in the main board. Does the main board tell the fan motors when to cycle on and off? This unit is only about 4 years old and it just blew a fan wheel yesterday. I had the condensor fans jumped on to keep the unit running (until yesterday, now it is off) but I want to get this thing fixed once and for all.
Any suggestions are appreciated.
10-18-2007, 06:51 AM
The condeser fans turn on and off through the CCB based on ambient temps that can be adjusted in the units controller. The first stage fan will come on with a call for compressor operation. Was anything done to the main board?
The main control board has not been adjusted, I went through the menu and nothing jumps out at me as far as the condensor fan settings. It seems strange that both ccb boards are doing the same thing, the old ones are still in a box in the unit, they were swapped out in the summer, there was a communication board on site so I swapped it a couple weeks ago but it did not make a difference. It does show in the menu (forget where) the boards are not communicating.
Thanks for the reply.
10-18-2007, 08:48 AM
Weird, That both circuits are doing the samething! The only thing they have in common is the motherboard. The CCB's are recieving comm from the motherboard because the compressors are coming on.
I assume the communication to bring on the fans comes from the mother board, there is another unit with a bad mother board on the roof, we are trying to get the customer to buy one and see if ti fixes the condensor fan problem if not we will use it in the other unit. I just don't like this trial and error stuff.
10-18-2007, 05:28 PM
Did I read that correctly? You have 2 units doing this? Are you going to upload the Config string into the motherboard yourself with your laptop?
Did you try and do a cold reset on the motherboard?
Has anyone else tinkered with this unit? The motherboard automaticaly performs an Archive every night at midnight for updated changes that have been made to it (i.e. setpoints, schedules, yada yada)?
You are not doing trial and error.......you are troubleshooting. Why not take the board out of the one unit and put it in the one with the bad board and see if it works, only takes a few minutes.
10-18-2007, 08:40 PM
call McQuay service to reprogram
Thanks for the replies, I will try to swap a board out now that the weather is cooler, the last time I was up there looking at the boards it was very hot and I was very busy. The tech on site called McQuay service a while back and he tried to reset the board in another unit by removing the battery and cycling power. We swapped that board out with another and it is running (other unit is still down). I don't know if he tried to reset this unit however.
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