Boiler Code - 2 LWCO?

Dow Stephens

I need to know at what size new steam boilers requires 2 low water cut offs. This is for New York City. What is the code reference? Thanks, Dow Stephens

tim smith_2

dual low water cutoffs

In Seattle all low pressure steam boilers require 2 low water cutoffs and 2 pressure controls, 1 being manual reset. I think that it's part of the national boiler code and alot of cities adopt this.

Greg Roder

Boiler Code

ASME (Section 4, Article 6) indicates that only a single low water cut-off device is required.

ASME CSD-1 (Part HG) indicates that two LWCO's are required with the lower of the two to be manual reset with lockout. However, there is a note in ASME CSD-1 that if the steam boiler is installed in a residence and is gravity return only one LWCO is required.

Neither of the above have any statments about size (BTU rating, etc.) of the steam boiler.

There are other codes and standards (IMC, ANSI, NFPA, etc.) that have statments about LWCO's but none, to the best of my knowledge, have any reference to the size of the steam boiler.

Keep in mind that local jurisdictions (city, county, state, etc.) can add, delete, or modify code requirements. Insurance companies may also recommend or suggest there be additional controls.

Dale

Insurance co.

If the boiler is over 400K input and not in a residence the insurance company usually has a gas train including LWCO requirement.

Greg Roder

Steam vs. Hot Water

The orginal question is about the 'size' of a STEAM boiler. Codes referenced and information given was for STEAM boilers.

There IS a size break of 400,000btu for HOT WATER boilers.

DO NOT mix the two.