Annual Boiler Shutdown & Service Procedures

At Howell Mechanical, we offer boiler maintenance and servicing for residential, commercial, and industrial clients. This means we service both heating boilers and process boilers – two very different beasts with distinct servicing processes. In this article, we’re going to briefly examine how heating boilers are serviced, then examine how process boilers are shut down and serviced.

What’s Involved in a Heating Boiler Service

Heating boilers – those used by residential and commercial clients for central heating – need to be serviced at least once a year. Doing so helps improve the lifespan and efficiency of your boiler, and it’s often required by manufacturers in order to keep your warranty intact.


Your boiler will be shut off when this process begins, so it’s best to do it in spring or fall. Your technician will visually inspect your boiler, then open it up to begin servicing.


Once the boiler is open, your technician will test all components of the boiler to ensure they’re functioning properly. This includes testing the heat exchanger, the burner, and more. Components like the burner will also be cleaned.


Your technician will also test gas lines, ensure that connections are tight and secure, ensure there’s enough corrosion inhibitor, and test and maintain any additional components like magnetic filters. From there, they’ll reassemble the boiler.


Of course, if there are any problems that need to be repaired or more maintenance that’s required (like a power flush), your technician will let you know. Servicing a heating boiler is fairly straightforward if you have the required technical knowledge – but it’s absolutely essential to have it done on a yearly basis.

Servicing a Process Boiler

The most important step

Do not, under any circumstances, shut down a process boiler if you don’t know what you’re doing. Process boilers are extremely hazardous, and the shutdown process is a delicate one. Consult the boiler manual before doing anything, and call our technicians to help. 

Before the shutdown

For two weeks before the shutdown date, you’ll want to double your blowdown rate. In addition, you’ll want to increase the amount of sludge conditioner you use by 1.5x-2x. Keep an eye on water quality during this period. This is an essential part of the process if you don’t want to scrape sludge from your boiler by hand.


The shutdown process

The boiler, piping, and equipment should all be visually inspected before you begin the shutdown process. Look for leaks, hot spots, and other problem areas. Listen for any strange noises. Make sure that everything is properly aligned.


Reduce the load and firing rate of the boiler – blowdown the boiler, as well as the level controls and column. 


You’re going to drain the boiler, so this is an excellent time to perform a slow drain test to ensure your level safety devices are functioning properly. Slow drain tests mimic low water scenarios quite accurately, so this is a perfect time to ensure your level safety device cuts off fuel when water levels are dangerously low.


Once the boiler has stopped producing steam, you can begin the manual shutdown process. This involves isolating the boiler using manual shutoff valves. If there are multiple boilers on the same system, follow Lockout/Tag out procedures to ensure safety.

Let your boiler cool slowly

Sudden changes of heat can cause serious damage to your boiler and peripheral equipment. The boiler maintenance process takes time, and time is money – wanting to rush the process is understandable. But trust us – the amount of money you might lose from a couple of days of downtime to let your boiler cool on its own is nothing compared to the amount you’ll lose if you need to replace your boiler entirely. 

Servicing your boiler

Once your boiler is shut down and adequately cooled, the servicing process can begin. Your boiler will be drained and thoroughly inspected. Any worn parts can be replaced, safety valves can be certified, and components can be cleaned and maintained. Your water treatment company should be part of the inspection, as they can look for pitting, corrosion, and scale and adjust the feedwater treatment plan accordingly. 


During the servicing process, tubes and gaskets will be inspected and, if need be, replaced. Burner baffles and diffusers will also be inspected for warping and cracking and replaced if necessary. The pilot spark electrode may need to be replaced, as may water cutoff probes and safety devices. In short, everything is inspected and replaced if need be. 

Storing your boiler

If you don’t need your boiler inspected, and it’s only going to be shut down for a few days, you can opt for wet storage. With wet storage, your boiler is filled completely with chemically treated water to prevent corrosion and rust, all while reducing startup time and saving a lot of water. 


For boilers that need to be inspected, and those that will be shut down for longer periods of time, dry storage is essential.


Both of these storage methods require you to carefully seal and treat your boiler. Not sure how to store your boiler? Give us a call. We service boilers in Winnipeg, and we can guide you through the process. 


Whether you’ve got a heating boiler or a process boiler, regular maintenance is essential – though one is much more complicated than the other. As always, safety comes first, so always call an experienced technician to help with servicing.