H Hydronic System Classifications by ASME

Low

• Temperature: 250°F or less
• Pressure: 125 PSI or less

Medium

Temperature: 350°F or less
• Pressure: 150 PSI max

High

Temperature: 350°F-450°F
• Pressure: 300 PSI

Boiler

Produces hot water (150°F-180°F) or steam
• Uses:
• Raises temperature in the building
• Provides hot water

Pump

Circulate move water

Heating Coils

Adds heat to the air, making it warmer

1. Pre-Heat

• Tempers outdoor ambient air
• Reduces load on the primary heating coil

Primary Heat

Heat air to desired temperature

Re-heat

• Used for humidity control
• Raises temperature in areas needing
higher output temperatures

Chiller:

• Makes water cold to cool down the building
• Produces cold water (40°F-55°F)
• Temperature/Pressure: 40°F-55°F/125 PSI or less
• Uses - Lowers temperature in the building

Colding Coil

Takes heat out of the air, making it cooler

Dual Temperature Water System

Combination System:
• Dual-purpose/2 in 1
• Does both heating and cooling
• Provides flexibility in temperature control