This article teaches you what to do when your chiller’s microprocessor returns a 999 error code. This error is often cause by a voltage spike that has corrupted the internal programming.
Chiller microprocessor controller shows a “999” error code. In some cases the chillers compressor(s) may remain running below the desired set point.
A high voltage spike or other supply power event to the chiller has corrupted the microprocessors internal programming.
In many cases, this issue can be resolved by running the factory default setup program that will copy all factory programming from the microprocessors flash memory to active memory. In doing so any corrupted programming files will be overwritten by fresh programming.
To run the factory default setup program:
Turn power to the chiller on.
Turn microprocessor on by pressing and holding the power button for 3-5 seconds.
Press and hold (all at the same time) the “UP” and the “ System Pump” buttons for 3-5 seconds. The micro should respond with “CFG” (looks like CF6) in the top screen. If this does not work try the “UP”, “DN” and “ System Pump” buttons. Once you see CFG in the top screen:
1. Press set: DEG – Set for C/F
2. Press set: CP – Set to “1” if you have one compressors or “2” if you have two compressors.
3. Press set: TC – Set to “IN” for NON TANK models and “OUT” for tank model chillers.
4. Press set: SP1 – Set for desired temp. Note: Do not set lower than 45F
unless you are running glycol
5. Press set: SP2- Set for desired temp. Note: Do not set lower than 45F
unless you are running glycol. Note: This setting will not show is CP was set to “1”.
6. Press set: DIF1 – Set for 2
7. Press set: DIF2 – Set for 2. Note: This setting will not show is CP was set to “1”.
8. Press set: HP1 – Set for 375
9. Press set: HP2 – Set for 375. Note: This setting will not show is CP was set to “1”.
10. Press set: LP1 – Set for 54
11. Press set: LP2 – Set for 54. Note: This setting will not show is CP was set to “1”.
12. Press set: HTA – Set for SP1 + 15F
13. Press set: LTA – Set for SP1 – 10F
14. Press set
15. Press set
16. Press set – UPD – Press set. The screen will flash and all updates will
be writing to active memory.
After loading and programming the factory default program, the chiller
should run normally. If above do not resolve the matter, this would indicate that your controllers internal memory has been damaged to the point that it can’t load the updates properly over to active memory. If this is the case the controller will need to be replaced.
Replacement controllers can be purchased through our website at:
All Legacy Chiller Systems models with PSG brand microprocessor controllers.