Circulation Pump - Water Switch Pump Nuisance Tripping - Bosch SHI4302 Manual

VIII. Troubleshooting
VIII. Troubleshooting
Circulation Pump
Circulation Pump
There have been some nuisance tripping of thermal motor protectors on
three-winding circulation pumps for use with water switches (# 239129).
To prevent nuisance tripping, use pumps with upgraded thermal
protectors (# 437345). If upgraded pumps (# 437345) aren't available,
use original circulation pumps (# 239129) with new (PTC) motor starters
designed to prevent nuisance tripping (# 423023).
IMPORTANT: Using new & original
pumps & motor starters:
• Use "new" circulation
437345 (with 135ºC OVLP) only
with "original"
182318 (4.7 – 4.8Ω).
• Use "original" circulation pump #
239129 (with 120ºC OVLP) only
with "new" motor starter # 423023
(15Ω).
TECH NOTES: New motor starter # 423023 (15Ω) has a larger resistance to limit current
draw through pump motor start windings. Winding temperatures are reduced, but starting
torque is reduced as well. So, new motor starters (# 423023) should never be used with new
circulation pumps (# 437345).
HINTS: Typical repairs will involve either replacing "original" circulation pump # 239129 with
"new" circulation pump # 437345 (preferred) or replacing "original" motor starter # 182318
with "new" motor starter # 423023.
TECH TIPS: All circulation pump motors use auto-reset thermal protectors.
windings cool below a preset temperature, protectors reset and pumps will work again.
thermal protectors fail to reset, replace pumps.
- Water Switch Pump Nuisance Tripping (1)
- Water Switch Pump Nuisance Tripping (1)
pump #
motor starter #
73
Once motor
If