How Bottom Blow Downs Work With Miura Boilers


To keep a Miura boiler running for as long as possible at optimal levels, there are a number of maintenance chores that must be performed every now and then. One such piece of upkeep is called a bottom blow down. This is something that must be done intermittently in order to remove particles, sludge, and any other type of sediments that may have settled at the bottom of the boiler and started to accumulate in the piping.

One of the benefits of a Miura boiler is that the BL controller will let you know when it’s time to perform a bottom blow down. When it’s time to perform the bottom blow down, it’s sometimes wise to allow the pressure inside your boiler to drop below 30 PSI. However, this step can sometimes be optional. As long as the piping for your bottom blow down is secure, you can perform the blow down at full pressure. Just keep in mind that you also have to follow any local codes or regulations that may exist in your area before starting the bottom blow down.

Also, before starting your bottom blow down, it’s important to be aware of your equipment. Every Miura boiler has one fast-opening blow down valve. Some models will also have a second slow-opening blow down valve. This second valve is required for boilers that have a maximum pressure that exceeds over 100 PSI. If this describes your boiler, make sure you note the position of both blow down valves.

The fast-opening valve is what isolates the blow down piping so you can dispose of the sediment that has built up over time. The second valve, if it’s there, is for safety purposes. It will help to start and stop the flow during the bottom blow down, reducing the risk of water hammer in the blow down piping.

Once you’re ready to perform the bottom blow down, the first step is to turn off the operational switch on your Miura boiler. You also have the option of closing the main steam vale. The next step is to slowly open the fast-opening valve and then do the same for the second valve. Doing this will drain the boiler of any particles or sludge. You will want to keep the valves open until the flashing B on your Miura boiler’s control panel disappears. Once the water level drops below the conductivity probe, the flashing B should disappear to confirm that the bottom blow down has been completed.

Once the flashing B is gone, you can close the valves in the reverse order in which they were opened. That means the slow-moving valve should be closed first and then the fast-moving valve. If the valves aren’t left open long enough, the flashing B won’t disappear, letting you know that the blow down is still necessary. Of course, if the vales are open too long, you risk draining too much water from your boiler. When your boiler is refilled, it could experience a low pH, making it vulnerable to corrosion.

Once you have confirmed that the blow down is complete and closed the valves, the main steam valve can be opened. Then you can turn the operational switch on your boiler on again and resume normal operations. As long as you follow these steps, performing a bottom blow down on your Miura boiler can be done without any hassle.