It’s that time of year when seasonal boilers should be prepared for the heating season. Before flipping that power switch to the “ON” position, however, the entire steam distribution and condensate return system needs to be surveyed to ensure it is ready for safe and successful operation.
- Perform a system inspection tracing fuel lines, feed lines, steam and blow off piping, stack, and regulator vent lines, particularly if work has been done on or near the boiler.
- Check controls and control panels for evidence of damage and changes or loose connections.
- Inspect mechanical assemblies such as burner linkage and safety valve springs for paint, dirt, and rust accumulation which wouldn’t allow easy movement.
- Check all ventilation and combustion air openings for cleanliness and free from debris.
- Review the manufacturer's operation, maintenance, and instruction manual for startup instructions. Become familiar with the timing sequence of the automatic controls.
Standard Startup Process
A review of boiler startup procedures can be summarized in the following list. Your actual system may vary, but this guide provides an outline of common items to check. For a dry start, the boiler will have to be filled with treated water. For a wet layup boiler, the water level may have to be dropped and chemistry adjusted before bringing it online.
- Check all valves and place them in their startup position.
- Open the sight gauge and water column high- and low-water shut-off valves. Make sure the water level safety controls are blown out and operational.
- Close the bottom blowdown valves, then open the upper drum vent valves.
- Start filling with soft water (preferably warm treated feedwater).
- Manually inject boiler water treatment chemicals, including oxygen scavenger chemicals, so the chemicals are added with the fill water.
- Once full to the operating level, open the fuel system and fire the boiler. Observe the burner flame to ensure proper firing and alignment. Carefully bring the pressure up to 10-15 PSIG, with the vent valve open. The boiler's warm-up curve should be strictly followed. The standard warm-up curve for a typical boiler is not to increase the boiler water temperature over 100°F per hour. Check your manufacturers’ guidelines.
- After the pressure reaches 10-15 PSIG, close the drum vent and slowly bring the boiler up to operating pressure.
- Once the unit has warmed, turn the power switch to "OFF". Verify the shutdown cycle, and then restart. Let the boiler come up to full firing rate and open the steam isolation/stop valves to bring it fully online.
- Monitor the boiler throughout the day, looking at the flame, stack outlet, controls, and linkage. Verify gasket tightness for both the waterside and the fireside.
- If any abnormal condition occurs during start-up, turn the power switch to "OFF". Investigate the cause before restarting the boiler.
- Collect a boiler water sample and test for the proper chemical concentrations. Adjust as needed.
After Startup
The entire steam distribution and condensate return system needs to be checked now that the boiler(s) is up to pressure and a walkthrough done to ensure proper operation at all pressure-reducing valve (PRV) stations, steam trap operation, and condensate return system.
Conclusion
In summary, the proper startup of a boiler system is one step of many required throughout the year to keep the boiler operating efficiently and safely. Be it the startup, shutdown, offline layup, or operating throughout the year, each works together to keep a system problem-free for the long haul. Following the proper mechanical and operating procedures is just as important for seasonal start-ups as water chemistry.
Water treatment is a critical part of the preventative maintenance program for any boiler system. Chem-Aqua provides customized water treatment solutions for all types of boiler system designs and applications. These solutions protect boilers from the harmful effects that may cause production losses or unexpected shutdowns, ensuring safe, reliable, and cost-effective steam production for years to come.
Written by: Tony Self