When you think of March, you may think of full-court press, lucky shots, and of course, the almighty bracket. When water treatment specialists think of March, we think of layups – for your boiler, not on the court. Layups are an essential part of your playbook to keep corrosion from damaging your boiler in the offseason.
Even though your boiler is idle, corrosion isn’t. In fact, more corrosion occurs when your boiler is idle as the oxygen content can significantly increase. Proper draining, cleaning, inspecting, and repairing prior to the layup process is vital to extending the life of your boiler, minimizing future maintenance costs, and preparing your boiler for a smooth re-start in the winter.
Let’s keep the madness on the court, and out of your Water Treatment Program. So, where do we start? First, determine which process will work for your systems.
Layup Lowdown
There are two types of layup processes: dry and wet. Which should you choose? Ask yourself these questions, first.
- How long will the boiler be out of service?
- How much notice will I have before bringing it back in service?
- What temperatures will the boiler be exposed to while out of service?
A dry layup drains the boiler, dries the internal surfaces, and remains empty during the offseason. If your boiler will be out of service for more than a month and temperatures could fall below freezing, dry layups are recommended.
A wet layup treats the boiler with corrosion inhibitors and remains full of water during the offseason. If your boiler will be out of service for less than a month and temperatures will remain above freezing, wet layups are recommended.
So, you’ve decided which is best for you and your Water Treatment Program. What’s next? It’s game time for your layup process.
Whether you’ve chosen a dry or wet layup, both processes have the same initial steps. To start your layup, shut off your boiler and allow the water to cool. Once cooled, fully drain and flush your boiler. Next, thoroughly clean the boiler. During this phase, inspect your boiler for any damage. Pay attention to any signs of leakage, corrosion, or areas that could cause potential future issues. Before moving any further in the layup process, perform all necessary repairs.
And just like man-to-man vs. zone defense, dry and wet layups have different plays once repairs are complete.
Dry Layup
After cleaning and any repairs, thoroughly dry your boiler using warm air. Electric heaters can help speed up this step. Next, place trays of desiccant – a substance that is used to absorb water and maintain dryness – into the boiler. There are different desiccants that can be used, but each require different volumes. Here are our recommendations:
- Quick Lime: 6-10 lbs/100 cubic feet OR 7 lbs/1,000 lbs steam rate
- Silica Gel: 7-10 lbs/100 cubic feet OR 8 lbs per 1,000 lbs steam rate
- Activated Alumina: 7-10 lbs/100 cubic feet OR 8 lbs per 1,000 lbs steam rate
Pro-tip: Trays of desiccant should be raised so air is able to circulate underneath them, avoiding any moisture build up underneath.
Finally, seal the boiler, blocking any openings air or steam could enter to ensure a sustained out of service season. During the offseason, make sure to check the desiccant every two months, replacing as needed.
Wet Layup
After cleaning and any repairs, refill your boiler adding water treatment products to protect against corrosion. There are two recommended treatment options.
Option 1:
- DEHA 20%: 1.5-2.0 gallons/1,000 gallons of water
- Polymer/Dispersant 20%: 1-2 gallons/1,000 gallons of water
- Cyclohexylamine 40%: 1 gallon/1,000 gallons of water, or as needed to maintain pH 10.0
Option 2:
- Solid Blend CLS Sulfite: Maintain minimum residual of 400 ppm as Sulfite, 635 ppm as Sodium Sulfite
- Solid Blend BT 400 Alkalinity Builder plus Phosphate: 1 gallon/1,000 gallons of water to maintain minimum Hydroxide alkalinity of 700 ppm, pH of 10.0 or higher, and Phosphate residual of 75m ppm
Pro-tip: Set your boiler to “low-fire” to circulate the water. Water circulation will ensure chemicals are properly mixed.
Finally, fill the boiler completely to 1 psi above atmospheric pressure. Make sure to block off any outlets to avoid water entering the steam header or superheater. During the out-of-service time, make sure to test your boiler weekly to ensure chemical residuals are maintained.
For a full play-by-play of boiler layups, check this out. Does this have you thinking through your spring-cleaning list? Make sure your cooling tower is at the top of your list. Check out our blog here for the full rundown. Need help with your Water Treatment Programs seasonal processes to avoid any upsets? Contact us, today.