Low Water Cutoff Device Needed?

broncosejr

Hi All,

New homeowner here and I'm trying to figure out if I need a low water cutoff device.

Our home inspector wrote in his report "It may be wise to have a low water cutoff device installed. This will help ensure the boiler will not operate without the proper amount of water in it. "

So I don't know if it's necessary or not. How can I determine if it's a smart move or just a waste of money?

CantabHeat

Yes, you should have one and it’s likely required by code. 

broncosejr

Thank you! Much appreciated.

CantabHeat said:

Yes, you should have one and it’s likely required by code. 

bburd

If your heating system is steam, a low water cutoff is a critical safety device and is required by code. The system should not be operated without one.

If your heating system is hot water, a low water cutoff was not traditionally required by code in single family homes. Most hot water systems have an automatic water feeder (aka “pressure reducing valve“) to prevent dry firing the boiler if there is a leak. It would certainly be a good idea to have one, however. Local codes vary.

broncosejr

bburd said:

If your heating system is steam, a low water cutoff is a critical safety device and is required by code. The system should not be operated without one.

If your heating system is hot water, a low water cutoff was not traditionally required by code in single family homes. Most hot water systems have an automatic water feeder (aka “pressure reducing valve“) to prevent dry firing the boiler if there is a leak. It would certainly be a good idea to have one, however. Local codes vary.

Thank you so much. It is a hot water system though. So may I ask.... why would one be necessary if it has the "pressure reducing valve"?

bburd

As a backup safety device. Things occasionally go wrong with pressure reducing valves.

It’s a question of how much risk is reasonable vs the cost of safety devices. The US regulatory environment is increasingly risk-averse, partly driven by the fear of lawsuits. Home inspectors are not immune to this, and tend to recommend upgrades to modern code that are not legally required for existing installations. Sometimes they even cite such things as deficiencies; the most notorious example is when electrical outlets in older homes are ungrounded, which met code  when they were installed.

I have seen low-water cutoffs on hot water heating systems only in large commercial buildings, never in a single-family home. There is additional risk if part of the system is installed below the boiler though, a floor slab coil or radiators in a basement for instance.

broncosejr

bburd said:

As a backup safety device. Things occasionally go wrong with pressure reducing valves.

It’s a question of how much risk is reasonable vs the cost of safety devices. The US regulatory environment is increasingly risk-averse, partly driven by the fear of lawsuits. Home inspectors are not immune to this, and tend to recommend upgrades to modern code that are not legally required for existing installations. Sometimes they even cite such things as deficiencies; the most notorious example is when electrical outlets in older homes are ungrounded, which met code  when they were installed.

I have seen low-water cutoffs on hot water heating systems only in large commercial buildings, never in a single-family home. There is additional risk if part of the system is installed below the boiler though, a floor slab coil or radiators in a basement for instance.

Thank you so much. Massive help!

Steamhead

I think @DanHolohan wrote an article about this a long time ago...............

Ctoilman

If it's a pre-existing hot water boiler, a low water safety control is highly UN-likely necessary.  It's an added luxury that will fail in the future as well.  

EBEBRATT-Ed

@broncosejr

Steam boilers must have low water cutoffs. On hot water they were not required in the past. Some codes require them on new installations.

Every boiler should have one

Look at it this way

A Lwco installes will cost you $$$.00 dollars

A boiler lost to a low water condition will cost you $$$$.00 dollars

STEVEusaPA

I have a lwco on my boiler and leave the feed off. I'd rather not have a pipe burst or a leak with the feed operating constantly, flooding the house.
I also live in a split level and enter/exit thru the lower level, so I walk by the boiler 2x a day and look at the gauge.
I always thought it wouldn't be a bad idea to put one at the top of the system, as a low water warning device. Doesn't have to turn off the burner, just a warning light to let you know you lost a little water and may want to investigate.

HomerJSmith

My jurisdiction was requiring one. Some times a pressure switch is acceptable to the inspector which many boiler manufactures incorporated into their boilers. I have always installed one where the radiation is below the boiler.