The atmospheric gas fired "T" Models are capable of 300,000 to 6,800,000 BTU input, temperatures up to 400 ° F., and pressures up to 300 PSI. Inside the "T" models' heavy insulated steel cabinet, staggered tubes provide 10-pass self baffled heating surface for high efficiency. Designed with flexability in mind - the "T" model permits free expansion and contraction, eliminated warping and leaking. An automatic burner controls provide 100% flame safeguard with manual reset, dual electric gas valves and gas pressure regulator.