On Boiler Maintenance for Steam...

JohnNY

The change of seasons is such a beautiful part of life in New York.



Except for that boiler thing.



Did you forget about what it takes to keep your boiler running safely and efficiently throughout the heating season?



Here’s a primer for your gas-fired, steam-heating boiler:



Burner tubes

In most gas boilers, fuel flows into horizontal tubes, mixes with air and is burned to heat the water contained in what is called the heat exchanger.

When dirt and dust build up on those burner tubes, efficiency declines because complete combustion of the air/fuel mixture is impeded. As a result of rising levels of unburned fuel after the combustion process has taken place, carbon monoxide begins to rise proportionately.

The heat exchanger may also become coated with carbon brought on by the burning impurities creating far greater carbon monoxide risks.



Low water cut offs

There are two basic types of low water cut off devices: the float-type (most often used is the McDonnel-Miller model # 67) and probe-type (yours would probably be the PS-800 series also by McDonnel-Miller). The float type should be blown down (flushed) weekly. It is made to last for ten years. After that, get a new one. Bad things can happen when they fail.

The probe type should be disconnected from the boiler and cleaned and inspected annually. It is made to last fifteen years.





If you think you’ve been maintaining your boiler because every week or so you push down on that lever that lets out that dirty cruddy water, you’re wrong. You haven’t done much of anything for the boiler at all. That valve is there only to maintain the low water cut off device to which it is directly connected.

Fresh water corrodes a boiler. Every time you flush it out, you’re creating the need to add more fresh water. If that new water doesn’t boil right away, it corrodes the cast iron and steel that surround it.



Flue and chimney

Flu piping and chimneys need to be looked at by someone who knows how a problem presents itself. Surface rust and discoloration are signs of something going wrong.

The causes are often one or a combination of the following: inadequate intake (or make-up) air for combustion, a collapsed or compromised chimney, or a serious issue inside the boiler.

The grey, metallic flue piping should connect to the boiler, its lowest point, and continue upward from there to the connection to the chimney. There it should be sealed to the bricks without gaps or holes in the penetration.



Skimming

Newer boilers need to be skimmed to get rid of the oil used in manufacturing that lies on top of the water, which prevents steam from rising and moving toward the pipes and radiators.

Every boiler contains an installation package naming a very specific connection, factory-installed in the boiler called a skim port or surface blow-off location where the skimming procedure is best performed. It is the installer’s duty to screw a pipe and valve into that connection to allow for the safe and effective removal of oils from the boiler water.

If this is not done, efficiency, boiler longevity and system balance suffer.

In the boilers I see, about one in four has any provision for skimming installed.



Pressure

Steam heating systems operate on the principle that steam pressure created in the boiler moves the steam to areas of lower pressure throughout the building. Areas of low pressure are created by adding air vents in places like the ends of radiators and piping runs. It doesn’t take a lot of pressure to do this, little more than just enough to be different from one end to the other of the system. That being the case, having the boiler run long enough to make more pressure than is necessary is nothing but an expensive waste of fuel and money.

A trained boiler mechanic and technician knows how to set the pressure regulating device, found on every steam boiler, properly.



The device is mounted on a curled length of pipe called a pigtail which protects it from the hot steam in the boiler. The pigtail should be made of brass (yellow metal) by Code as of July 2008. If yours is made of steel (black in color) have it replaced. They inevitably clog and fail.



Insulation

The NYC Building Code now requires all *new* boiler piping to be insulated.

But, there are two schools of thought here: one is that the heat produced by the boiler is best utilized if carried to the heat emitters (radiators, etc) in its hottest form with minimal transfer losses. The other is that heat lost in transfer to within the envelope of the building is not lost at all.

There are some valid reasons to insulate or not insulate sections of piping, but right now new boiler piping should be insulated after a reasonable period of being in operation and observed to be free of leaks.



While I'm on a roll (rant?) here:



A word on Water Feeders

Increasing occurrences of having to add water to a steam boiler is NOT a reason to buy an automatic water feeder.

If your boiler is less than 400,000 BTUs (in your 1-to-3-family building, your boiler is probably less than 400,000 BTUs) and you’re adding water more than about every two weeks, you’ve got a problem that needs to be identified and repaired. Adding a water feeder to deal with it would be like putting a band aid on a gunshot wound. You haven’t solved your problem.

Water feeders have their place and their people.

I happen to be a fan of the Hydrolevel VXT model.

There are countless benefits to their digital display (in number of gallons fed) and their flexibility made possible by their settable flow rate options (how much water per feed cycle) and its lockout feature which effectively prevents things like flooding a house while the family’s away.

BobC

Maintanence

Great information that is well laid out.



I've always used a valve to feed water into my boiler, automatic water feeders are just an avoidable point of failure IMHO. The auto feeders tend to make people ignore the boiler till something happens, and by then it can be expensive.



Because I have a ETI on the oil burner, I'm downstairs every day anyhow to fill in the log. I always feed any needed water at the very start of a firing cycle, while boiler is relatively cool.



Bob

JohnNY

Oddly,

I've got people on local homeowner's forums online explaining to others that there's really nothing you need to do to a boiler to keep it running.



And just because it still warms radiators and has yet to flood the house or burst into flames, they use this to prove their point.



So this was my two cents to them.



It's fun once you start writing :-)

jpf321

nice picture...

I like the idea of the super-low LWCO.

Is it NYC Code now to have 1 LWCO as manual reset as well as 1 pressure control be manual reset? Maybe you want to point that out in your picture?



The only critique I have of the picture is the use of Black on thepressure tree, I think that NYC now requires all pressure tree components in brass (and yes, I have a black tree right now on my new system http://is.gd/gqumT, which I haven't quite completed the install on and I will be changing it to brass as well) I understand that you put the pressure cleanout on there, but I think NYC says brass now.



Gorgeous header by the way, is this one of yours?

I try to stay away from Brownstoner if at all possible, although that is how I found you initially, too bad you don't service my hood.

JohnNY

Black steel or cast iron is permitted.

Code requires brass pigtails and cleanout tees on the black nipples into the boiler.



I don't love what my guys did with that secondary low water cut off, but the inspector seemed to like it too.