How low-water cutoffs protect your boiler, how often to test them, what a failed test looks like, and when to call for low-water cutoff repair in Houston.
The low-water cutoff (LWCO) is one of the most important safety devices on a commercial boiler. If the water level drops too low while the burner is firing, the heating surfaces can overheat, warp or crack. The LWCO senses the water level and shuts the burner down before that happens.
What a low-water cutoff does
Most commercial boilers use either a float-type cutoff or a probe-type (conductance) cutoff. A float cutoff uses a float chamber that drops with the water level and opens a switch. A probe cutoff senses water through an electrode; when water no longer touches the probe, the circuit opens and the burner stops. Many boilers carry both a primary and a secondary (manual-reset) cutoff for redundancy.
How often to test
Follow the boiler and control manufacturer's instructions and your jurisdiction's requirements. As a general practice, many facilities blow down float-type cutoffs regularly on steam boilers and perform a full operational test, where the water level is lowered and the burner is confirmed to shut off, on a scheduled basis. Keep a written log of every test.
What a failed test looks like
- The burner keeps firing after the water drops below the cutoff point
- Sludge or scale in the float chamber keeps the float from dropping
- A fouled or coated probe still reads water when there is none
- The manual-reset cutoff will not reset, or trips repeatedly
A failed low-water cutoff is a safety issue. Shut the boiler down and have it serviced before returning it to operation.
Inspections and records
Low-water cutoff operation is checked during boiler inspections, and inspectors look for evidence that safety controls are maintained. Keeping a test log makes inspections simpler. See our guide to boiler inspection requirements in Texas.
When to call for repair
If a cutoff fails a test, trips without a clear cause, or the float chamber is heavily scaled, call a qualified technician. Boilers on Demand provides commercial boiler repair 24/7 across Houston and Conroe. If your boiler has to come offline for repairs, temporary boiler rental can keep your facility running.
Call 936-300-4111 or contact us to schedule low-water cutoff testing or repair.
