Pentair UltraTemp Brownout Alarm
The BROWNOUT alarm on a Pentair UltraTemp indicates the 24 VAC supply voltage to the control board is low. This typically points to transformer issues or insufficient supply voltage to the heat pump.
This alarm requires electrical troubleshooting and may need a licensed electrician for resolution.
Understanding the Power System
The UltraTemp power system consists of:
- Line Voltage: 208-260V AC to the heat pump
- Transformer: Steps down to 24-28V AC for control board
- Control Board: Operates on low voltage from transformer
If transformer output drops too low, the control board triggers a BROWNOUT alarm.
Common Causes
Transformer Issues
- Transformer failing or failed
- Loose transformer connections
- Transformer undersized for load
Supply Voltage Problems
- Utility voltage too low
- Voltage drop in long wire run
- Undersized wire gauge
- Phase loss (for 3-phase units)
- Tripped breaker or blown fuse (one phase)
Connection Issues
- Loose wire connections creating resistance
- Corroded connections
- Damaged wiring
Troubleshooting Steps
WARNING: High voltage checks require extreme caution. If not qualified, contact a licensed electrician.
Step 1: Check Supply Voltage
- Use voltmeter rated for line voltage
- Measure voltage at heat pump disconnect
- Should read 208-260V AC
- Check each leg to ground (should be ~120V each)
- For 3-phase, check all three legs
Step 2: Check Transformer Output
- Turn off power to heat pump
- Locate transformer in electrical box
- Turn power back on
- Measure transformer secondary (output) voltage
- Should read 24-28V AC
Step 3: Evaluate Results
If Supply Voltage is Low (below 208V):
- Check for loose connections at breaker panel
- Verify wire gauge is adequate for distance
- Contact utility if voltage is consistently low
- Consider boost transformer if needed
If Transformer Output is Low (below 24V):
- Check transformer connections
- If connections are good, replace transformer
If Both Are Normal:
- Check wiring between transformer and control board
- Control board may be faulty
Voltage Requirements
| Measurement | Required Range |
|---|---|
| Supply Voltage (to heat pump) | 208-260V AC |
| Transformer Output | 24-28V AC |
| Each Leg to Ground | ~120V AC |
When Boost Transformer is Needed
If supply voltage is consistently low:
- Long wire runs from panel (voltage drop)
- Multiple large loads on circuit
- Utility voltage at low end of range
A boost transformer installed near the heat pump can raise voltage to acceptable levels.
When to Call Electrician
- Supply voltage is out of range
- Phase appears to be missing
- Wiring needs to be upgraded
- Boost transformer installation needed
- Any uncertainty about electrical troubleshooting
Prevention
- Ensure proper wire gauge for distance
- Use dedicated circuit for heat pump
- Have electrical connections checked periodically
- Monitor for recurring issues during high-demand times