Another way to modify firing is through oxygen trim control. This uses a flue to trim excess air when the boiler is not operating full blast. Excess air regulation control is like a supercharger that maintains a positive air flow for maximum combustion.
More advanced controls combine air and fuel limiters to add safety and increase fuel efficiency when stepping up or down on heating. Drum level control makes dry fire systems a little safer by monitoring drum water levels.
Consult both the boiler manufacturer and your local HVAC contractor to determine which controls are appropriate for you.
All boilers need a reliable water source. This may be connected to the city system or a dedicated well pump. It is important to maintain a steady water supply to keep boiler water levels at safe limits. Hot water boiler systems need the system to be full of water. Steam systems need t regulate water so there is only steam in the mains, not water. In a cold city like HVAC systems should have a ball valve between the water source and the boiler to stop major leaks.
Colorado code requires all HVAC systems to have a back flow preventer keep the water supply from being contaminated by the boiler. A pressure reducer valve is also needed to make sure the heating system does not fail over a certain PSI. If you are worried that your system is not safe, consider calling in a Denver heating repair contractor to inspect your HVAC for safety and local regulations.