Starter Transition Failure bF0 RTHA

Issue:

Starter Transition Failure - bF0

Resolution:

UCP1:  RTHA

See RTHA-SB-5A for troubleshooting and reference.

Questions to ask:

• Does the compressor turn over or even attempt to start?
  • • If there is no attempt to start; check the 2U1 Phase Monitor.
  • Does the failure happen within the first 3 seconds of operation?
  • Does the failure happen within 3-8 seconds of operation?
  • Is the failure a running diagnostic that happens after 8 seconds of operation?
  • Has the starter Dry Run test been performed?
    • Any problems with Dry Run Test?
• Is the problem intermittent?
  • Check wiring, connections, connections on contactors, fuse holders
  • Contactors all working correctly; especially 2K1 and 2K2
  • AUX contacts on contactor(s); especially 2K1 and 2K2
  • Possible internal contacts in the 1U2 (difficult to determine without an oscilloscope)
  • 2K5 (Pilot Relay) is notorious for these types of problems.
  • Check to make sure the HPC is not chattering.

• Remote Y-Delta Starter

  • The 2K2 auxiliary contacts that signal "transition complete" to the 2U1 starter module are often the cause of this diagnostic on a remote starter, too.

  • There may be a long run of control wiring from the starter to the chiller with associated voltage drop.

  • Voltage at the 2U1 from that contact should always be greater than 80VAC to ground at the module but voltage drop in any good installation will be smaller than that.

  • Inspect the wiring between the units and look for splicing, corroded terminals at a terminal board and the like.

Other Question/Problem/Cause Statements:

• Starter Transition Failure - bF0?
• Intermittent Transition failure?
• Momentary Power Loss (MPL) - bE2
• UCP1 controls
• Starter Transition Failure - BFO diagnostic

Facts:

• Water-Cooled Chiller (Pueblo) (RTHA)

Combined the following HUB Documents: DOC-83003 and DOC-86415