How do you wire a low water cut-off on a steam boiler?

Connect the neutral side of the boiler transformer to the burner. Using a wire nut, connect the neutral side of the water feeder transformer to the water feeder. Connect the wire from the burner to terminal 1 of the low water cut-off.

How does a low water cut-off probe work?

When water drops below the probe, an electronic “stop” signal shuts down the burner. The control is conductance actuated and relies on the mineral content of the water to complete the circuit. The purer the water, the higher the unit sensitivity needs to be.

What causes low water level in boiler?

A low water condition in a boiler happens when the water level drops below the lowest permissible water level, or even below the top of the tubes, allowing the tubes to overheat. In fact, if the water gets lower than the main firing tube, or “Morrison tube,” the steel itself may fail.

How does a low water boiler cutoff work?

The float mechanism actuates an electrical switch when the float reaches a preset level. Another popular form of low-water fuel cutoff is called a probe type. This variation uses rod-like electrical probes inserted into the boiler or in an external chamber.

How does a low water fuel cutoff work?

The most common type of low water fuel cutoff is a float inside a chamber. The float mechanism actuates an electrical switch when the float reaches a preset level. Another popular form of low-water fuel cutoff is called a probe type. This variation uses rod-like electrical probes inserted into the boiler or in an external chamber.

How to test for a low water condition in a boiler?

1 Simulate a developing low-water condition in the boiler by shutting off the feed pump and feeder valve supply. Allow the boiler water level to drop. 2 Observe the gauge glass. The water level should never go lower than the lowest visible part of the glass. 3 Restore the water level to normal and resume operation.

What happens when a boiler float gets too low?

The float is in an external chamber and it rises and falls with the boiler water level. If the float drops too low, the linkage opens the switch and trips the burner control circuit. If a float gets water-logged, it will naturally sink. When this happens the low water cutoff is tripped.

Why do you need a low water cutoff on a boiler?

Both techniques merely detect a low-water condition caused by some other problem in the boiler. For that reason, inspectors must look beyond a cutoff device failure to find the root cause of a boiler’s low-water condition. “Low-water cutoff devices are like anti-lock brakes,” Mr. Thomson says. “They help prevent accidents.”

Can a low water fuel cutoff be rendered inoperative?

A probe-type low-water fuel cutoff can be rendered inoperative if sludge or sediment is allowed to cover the probes or make contact with the chamber walls. This can occur if the device is installed in a water column or other external chamber that is not flushed out periodically.

Can a closed boiler be tested for low water?

First, a caution that the monthly test of a low-water fuel cut-off should not be applied to hot water heating boilers in a closed system because it requires a shutdown of the heating system (in a single boiler plant), the isolation of the boiler from the system, and drainage of all the water above the cut-off level.

What do you need to know about low water Cutoff controls?

Boiler low water cutoff control service or repair: Here we explain Low Water Cutoff Controls: Guide to LWCOs on steam heating and hot water heating systems and we provide a low water cutoff switch Troubleshooting & Repair Guide.