Issue:
Starter Transition Failure - bF0
Resolution:
UCP1: RTHA
See RTHA-SB-5A for troubleshooting and reference.
Questions to ask:
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Does the compressor turn over or even attempt to start?
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- 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?
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Has the starter Dry Run test been performed?
- Any problems with Dry Run Test?
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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.
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Remote Y-Delta Starter
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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.
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There may be a long run of control wiring from the starter to the chiller with associated voltage drop.
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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.
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Inspect the wiring between the units and look for splicing, corroded terminals at a terminal board and the like.
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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
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.