Continuing the search for “low hanging fruit,” this month I’ll cover some boiler room items
then get on to reducing electrical consumption.
Now brave reader, let us enter
that Stygian cavern: the abode of a
hellish trio of monsters Waste-A-
Watt the Boiler, It-Sucks the Vacuum
and Hiss the Compressor. Yes I’m
alluding to your boiler room.
In most cases it’s hot, humid,
dirty, poorly lit, painfully noisy and
can be dangerous. These are reasons
the boiler room equipment (despite
the fact that probably at least 70 cents of your utility dollar is spent there)
attention in the form of routine inspection and preventive maintenance that it’s entitled to.
Before getting further into this article I want to stress that boilers are one
of the few devices
in a drycleaning/laundry operation that can actually kill you so never do any mechanical
work on a boiler that is hot or is under pressure!
Last month, steam traps were the “perps.” This month, the first thing we’re going to check
out are the blow valves on the boiler.
Here’s why. Watch how long it takes for a slight flow of water to fill a five-gallon
doesn’t take long — about 30 minutes, or 10 gallons per hour.
If this same volume of water was leaking from your boiler through these blow
you’d be wasting about 120,400 BTU’s/HR. That’s around 3.5 boiler horsepower being thrown
The following will explain how to identify this type of loss.
Ever think about why the
elbows in the blow down lines
seem to spring “pin hole” leaks
more than other piping? When
you observe the faulty part, it
almost seems like the hole was
drilled because the area is so
small and well defined.
The cause of this problem is the
same process that created the
Grand Canyon — erosion.
In the case of the boiler piping,
this erosion takes on the
properties of “sand blasting.”
When you blow down the boiler,
hard particles of scale, rust and
other detritus are exiting the
boiler at high speed and keep
moving in a straight line (see
Newton’s first law of motion)
slamming into the elbow near the
90° bend. This impact blasts away metal.
Now let’s take a look at the valves used in the blow down piping.
In most boiler installations there are at least two “ball valves.”
Look carefully at a ball valve; it’s really a marvel of machining and chemical engineering. The
ball itself is usually polished stainless steel or chrome-plated brass rotating
inside a Teflon seat.
In order for these valves to seal properly, tight tolerances must be maintained
rotating ball and that seat.
When the valves are being opened or closed, the sand blasting effect erodes away
edges of the passageway through the ball as well as scouring the Teflon valve
As the spacing between the ball and seat increases, small abrasive particles
enter, adding to
the deterioration of the ability to contain the water and steam inside the
Unlike the testing for faulty steam traps, this test is an easy slam dunk. Wet
your finger or
take a spray bottle with water and test the pipe on the outlet side of the
valves identified in the
next steps. If the water flashes off or rapidly evaporates, that valve is faulty
and needs to be
Step 1: After the boiler is up and running for at least two hours with the back up,
the globe valve (these valves are generally found on boilers rated for over 80
pressure and will have a round handle on it. If it is not present go to Step 2).
Step 2: Check the temperature right after the water column blow down valve.
Step 3: Check the temperature right after the boiler shell blow down valve.
Valves used on boilers should be rated at the next higher level of the rated
For example if the rated operating pressure (usually found on the name plate
attached to the
boiler) is 150 PSI, then the valve should be steam rated for at least 200 PSI.
This rating usually appears on the body of the valve after the SWP abbreviation
working pressure” (you won’t find these valves at Home Depot or Lowe’s). These are not the
numbers following the abbreviation WOG which stands for the pressure rated for use with
In order to comply with code, piping and fittings between the boiler and blow
down tank must
be Schedule 80.
Well that’s about it for this issue, we’ll be dealing with more easy-to-fix, dollar-wasting
conditions next month.