The questions operators ask—and the answers that can save trouble 

By Kevin Marois

We get asked lots of questions every week. That’s great. We love answering questions because it means people are thinking. Plus, they are probably trying to take care of their equipment. Here are some we hear all the time. 

Why is my solvent milky? 

Milky solvent is usually a sign that there is water mixed in the solvent. The water could be coming from the steam coil or a problem with the water separator. Milky solvent can cause dye bleeding, shrinkage, and damaged garments. It can also be a problem when you try to distill that solvent. The solvent and water form an azeotrope, which boils at a much lower temperature and much faster than solvent. It will overload the still condenser and give you a water alarm.

Why do my shirts have yellow stains after I press them? 

This is caused by alkali left on the fabric. The shirt comes out of the washer looking white. After it is pressed, the heat from pressing will turn the alkali yellow, and it will be a very obvious stain. The solution is to just rewash the shirt. Either the washer is overloaded, not rinsing properly, or you are using too much detergent. In each case, detergent or alkali is being left on the fabric. It needs to be rinsed out before you press the fabric.

Why is my press cold and dripping water? 

Steam is used to heat the press. It comes into the press as a vapor, gives off its heat and condenses back to water. The water drains down to the steam trap and is sent back to the return tank. A steam trap that is not working properly will be cold and it will hold water in the press. The press will not be hot, and when you press the steam valve, you may get water or wet steam.

Why do you hit a steam trap? 

This is called percussive maintenance. Sometimes a piece of scale will be stuck in the trap, causing it to stick in the closed position. If you smack the trap a few times with a hammer, you may rattle the scale loose. Sometimes it will start to work again. Careful—if you hit it too hard, we may have to come and replace the trap or the broken pipe. 

Why is the water level in my boiler sight glass bouncing up and down? 

The most common cause for this problem is minerals in the water. When water evaporates, it leaves the minerals behind, and they build up as time passes. When the concentration of total dissolved solids is too high, foam begins to form. The foam carries water out of the boiler and into the machines. The water level in the boiler drops and the boiler shuts down because the pump can’t keep up. Increase the amount of blowdown to prevent this problem.

Why are there white crusty stains left after drycleaning? 

The white crusty marks that blow out very easily with steam are sugars and starches. They are water-soluble, not solvent-soluble. They do not come out in drycleaning, but they come out very easily with a little bit of steam. It is possible to pre-spot or to use some moisture in the machine to help remove them during the cleaning process.

Why do I need combustion air? 

When a boiler or a dryer is operating, it draws air from inside the room to burn the gas. That air is vented out of the building as exhaust. That air needs to be replaced in the room so that you don’t create negative air pressure inside the building. Negative air pressure may cause the exhaust from a water heater to be sucked down the chimney into the boiler room, and potentially expose people in the building to carbon monoxide. 

Why does wool shrink when you wash it? 

Wool fibers have cuticles, like fish scales. When they get wet, they swell up and stick out. When they stick out, they interlock, and once they have interlocked, you cannot release them. Wet cleaning detergents are acid-based and prevent the cuticles from swelling, so the fibers do not interlock. They simply slide past one another. You need three things for wool to shrink: moisture, heat and mechanical action.

Why is there a ring when I finish spotting? 

You have drycleaned a garment, then tried to remove a remaining stain and flushed the area with steam. When you’re done, there’s a ring. What you may actually be seeing is a clean piece of fabric. The rest of the fabric has soil left after drycleaning. It is in a nice even layer, so you cannot see it easily. The spot where you have done additional work has been flushed clean with steam, and in fact, it is cleaner than the rest of the garment that you drycleaned.

Why do I need detergent? (It’s expensive!) 

Detergent helps to remove soil by lubricating fibers. It then helps to hold soil in suspension until it can be removed. Otherwise, there is a possibility the soil may come off the fabric and be transferred to another piece of fabric. In drycleaning, detergent also helps prevent static. In hydrocarbon machines, detergent has a bacteriostat that helps to control bacteria in the tanks and the water separators, so you don’t get that foul odour.

How can I make a crisp crease in wool pants? 

The crease is made by moistening the wool fibers with steam, pressing them into shape with the head, and then vacuuming them dry in that shape. The vacuum is actually more important than the steam. The fibers need to be dried in the shape that you want, and then they will hold that shape. Everett Childers used to say, “A penny’s worth of steam and a nickel’s worth of vacuum.” 

That’s a lot of questions for one session. Next week, I’ll be asking YOU some questions, so stay tuned!

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