Summer’s here, and you’re not the only one who’s ready to take a vacation. Your heating boiler could use some time off from keeping the building toasty all winter. If you want your boiler to remain reliable for many winters to come, at the start of summer you need to perform a boiler layup.
What’s a Layup?
A layup is a procedure that essentially prepares the boiler to not run for a few months. There are two ways to perform a boiler layup: wet or dry. Dry layup is when the boiler is drained and washed out and left drained for an extended period of time. Wet layup is when the boiler steam space is flooded to reduce the amount of oxygen inside the boiler.
When to Use a Dry Layup
When should you do which type of layup? Generally, it’s industry-accepted that when the boiler is scheduled to be off at least a couple months, the dry layup method is best. This method removes the water from the metal surfaces of the boiler that can cause corrosion. When the boiler waterside is washed and dried out, very little corrosion will occur on the metal surfaces. To help keep fresh dry air in the boiler, an incandescent light can be placed in the manway, providing a small amount of heat that will help to keep the surface dry. Another method is to use desiccant inside the boiler. Once the boiler is washed out and dry on the inside, seal up all the waterside surfaces with the normal gaskets but put desiccant bags inside the boiler. These bags will absorb the moisture of the air within, and the bags can be renewed or replaced at intervals when saturated.
When to Use a Wet Layup
A wet layup is generally used when a boiler will need to run again within a couple months. Shutdown time can be as short as a week or as long as an entire summer. The benefit of the wet method is that it keeps the boiler in a state of readiness to operate, as the water only needs to be drained down to allow the boiler to start. In untreated city water, there is a lot of dissolved oxygen that will corrode the boiler’s metal surface. Thus, if you’re doing a wet layup, be sure to get the water warm in order to boil out the dissolved oxygen and increase the chemical level in the boiler. On large boilers, a pump is recommended to circulate the water inside the boiler to prevent stratification of the chemical and to provide even mixing throughout. The danger of wet layup is that the water is that if the waters isn’t treated properly, it will corrode the inside of the boiler causing tube leaks. So, it’s a good idea to consult with your water treatment company before performing a wet layup.
When it comes to which method you should use, there’s no right or wrong. Both options have benefits and are used on a case-by-case basis. If you’re unsure the best method for a boiler layup, contact your local water treatment company or even the boiler manufacturer. Both parties will give recommendations based on the site conditions and the timeline of the layup. The most important part of the whole process is preserving the waterside of the boiler between heating seasons to avoid accelerated waterside corrosion and expensive repairs.