This question is one we receive frequently, and today, we have the answer. Yes, MLI's can be installed on boilers AS LONG AS the following Code rules are met:
1. The maximum operating pressure is 900 PSIG (6 MPa). This eliminates the concern for deviations with level accuracy on frequent cycling applications at higher pressure service.
2. The indication scale limitations are between 2 inches above the danger point, as determined by the boiler manufacturer and the low side of the outside diameter of the steam connection exiting the drum.
3. The attachment of any external switches or transmitters to a Magnetic Level Gage for control functions is prohibited.
4. The use of a Magnetic Level Gage does not replace the Code required gage glass.
5. A Magnetic Level Gage may NOT be used to function as a water column. Other accessories such as a gage glass are prohibited from being attached.
6. Magnetic Level Gages must be installed with isolation and drain valves.
7. Refer to Subsections PG-12 and PG-60 in Section 1 of the Code for additional details.
For more information on this topic, download our brochure on "Understanding the Use of Magnetic Level Gages and ASME Code Compliance on Power Boiler Applications" by clicking here.