Cleaver-Brooks LOW WATER: Cleaver-Brooks Cleaver-Brooks H...

Symptoms

The Cleaver-Brooks Hawk 6000 controller displays a Low Water alarm. The water level in the boiler has dropped below the low water cutoff setpoint, causing an immediate safety shutdown to prevent boiler damage from firing with insufficient water.

Possible Causes

Boiler feedwater pump failure or feedwater valve malfunction
Makeup water supply interrupted due to low city water pressure or valve closure
Boiler blowdown valve leaking or left open after manual blowdown
Low water cutoff switch or water column float stuck or faulty
Leak in the boiler tubes or shell causing water loss

Troubleshooting Steps

Step 1: Check the boiler water level gauge glass to confirm the actual water level
Water level is visible in the gauge glass at or above the minimum safe level
Step 2: Verify the feedwater pump is running and the feedwater valve is open
Pump runs and feedwater valve admits water to the boiler
Step 3: Check the makeup water supply pressure at the boiler room
Makeup water pressure is adequate (typically 30+ psi)
Step 4: Inspect the blowdown valve for leaks or being partially open
Blowdown valve is fully closed with no leakage
Step 5: If the water column or float switch is suspect, blow down the water column to clear sediment
Water level in the gauge glass responds quickly and matches the actual level

How to Reset

To reset: 1) Restore the water level to normal. 2) Fix the feedwater or leak issue. 3) Press the RESET button on the Hawk 6000. Caution: Never restart a boiler that has overheated due to low water without a thorough inspection. Adding cold water to an overheated boiler can cause a steam explosion.

Common Replacement Parts

750-291: Cleaver-Brooks low water cutoff switch (Use a McDonnell-Miller or equivalent rated for the boiler operating pressure)

Frequently Asked Questions

Q: What is the low water cutoff?
The low water cutoff (LWCO) is a safety switch that monitors the boiler water level. When the water drops below the safe minimum, it opens the safety circuit, causing the Hawk 6000 to shut down the burner. This prevents the boiler from firing with insufficient water, which can cause severe overheating and potential explosion.
Q: What should I do if the water level is low?
Do not add water to a hot boiler immediately. If the boiler is hot from firing, allow it to cool before adding water to prevent thermal shock. Once cooled, restore the feedwater system, fix any leaks, and verify the water level is stable before restarting.

Cleaver-Brooks Cleaver-Brooks Hawk 6000 Controller Error Code LOW WATER