Steam boilers require a closed loop to carry high pressure steam around a building for heat and then back to the boiler. The beginning of the loop starts where the water is heated inside the water jacket. When the thermostat calls for heat, the pump kicks in and pushes superheated water through the loop supply line. The loop supply line is connected to the floor heating pipes, coils, or radiators like in old systems found in heating in Denver high schools built before central heat and state money. As the steam flows through these devices, it drops off its heat. Then it flows back into the impeller which pushes it back from the circulation pump into the heating element. Most commercial boilers have the circulation pump on the hook&loop return side, although some residential systems may have it on the supply side.
When working with and HVAC contractor, make sure they install the pipes for easy servicing. A professional HVAC service tech should install all the boiler pipe systems in accordance with Denver HVAC regulations. Isolation valves should be closeable so the circulation pump can be replaced without effecting the loop. Maintenance on boilers is much easier when air does not violate the integrity of the heat loop. If the loop is not breached, maintenance can be easily preformed and the air purge drains will quicken startup by eliminating the need to bleed air from the baseboards or radiators. HVAC technicians will be able to get routine repair work done much easier if these features are installed. Air trapped in water loops is a main cause of problems.
Hydronic lock, or air block prevents water from circulating in pipes if an air pocket forms. To fix this, contact a Denver boiler repair company to drain all the air. This can be a large job. Properly configured piping installed by a HVAC professional will be easy to flush, while older systems may take disassembly to fully drain all air pockets. A good HVAC job will allow air purge through simply hooking up a water hose and filling the system. Air purge devices can also malfunction and let air in instead of out. In Colorado, all boilers must carry ASME certification. All commercial boilers should carry this certification and will pass inspection. High performance commercial boilers take more thought to install, but once properly configured, your Denver HVAC technician should not need to do anything beyond routine maintenance.