1. COMMERCIAL BOILERS

2. HIGH MASS Advantages Flow Indifferent Primary Piping Resistant to low return temperature issues Up to 1200 H.P. 20 plus year life expectancy Disadvantages Least efficient Higher cost per BTU output Big Footprint Thermal shock

3. LOW MASS CFT Advantages Lowest cost per BTU output Small footprint Disadvantages Flow dependent Short cycles Vulnerable to condensate Required primary secondary piping Up to 15 years of life

4. LOW MASS FIRE TUBE Advantages Small Footprint Higher Efficiencies Disadvantages Flow dependent Requires high turndown ratio Primary secondary piping 316L Up to 10 year life

5. MEDIUM MASS FIRETUBE Advantages Flow independent Primary Piping Tolerant to low return temps 20 plus year life Small footprint Resists thermal shock Available in condensing & Non-Condensing No short cycling 5:1 turndown adequate Disadvantages More expensive than low mass

6. SUPPLY/RETURN SYSTEM 2 Way vs. 3 way valves Bypass Minimum Flow Rate High Mass Low Mass Medium Mass Type of Pipe Steel Copper PP-R