Maximize Boiler Efficiency with The PST System

The PST System - How to Maximize Boiler Efficiency

Boiler piping design that worked well in the times of monster boilers and cheap energy does not work for today’s small high-efficiency boilers. Our PST system is your solution. PST stands for ‘primary-secondary-tertiary’ pumping. This is a way to pipe the boilers that:

  • Saves energy by eliminating overheating in the spring and fall ... up to 25% over conventional systems;
  • Allows for different send-out temperatures for different zones;
  • Allows for much lower send-out temperatures which prevents overheating in mild weather for energy savings and greater resident comfort;
  • Keeps the temperature of the return water to the boilers high enough to ensure long boiler life.
  • Save capital and maintenance costs by eliminating separate boilers for multiple zones that require different temperatures including domestic hot water.

High-efficiency boilers require two things. They need a constant flow of water through them and they need return water temperature that is, in most cases, no lower than 130°F. The PST boiler system was designed to accommodate these needs.

This system has a boiler loop that always maintains a high temperature (typically 180°F to 220°F) and a constant flow. Each distribution zone is a closed loop. The injection loop has a variable speed pump or 4-way valve to meter hot water from the hot boiler loop into the distribution zone as needed. This gives accurate and immediate control of the supply temperatures.

In the PST system, the distribution loop can be any temperature. In fact, different zones can be different temperatures. Because of this, we can use the one boiler plant to heat zones with different requirements. We can also use the same boilers to heat domestic hot water, rooftop makeup air units, garage ramps, heated walkways or any other hydronically heated device.

More information on the PST System is available in this PDF article.