Thermal Solutions AMP-L condensing boiler and water heater is available in five sizes: 400, 500, 650, 800 and 1000 MBH. AHRI Certified and rated at 97% and 98% thermal efficiency respectively, the AMP-L is available in either a natural gas or propane configuration. Standard AMP-L models save time and simplify planning. Included at no additional cost are the low water cutoff and high and low gas pressure switch making the AMP-L CSD-1 compliant. Also equipped standard with a strength-adding 3-in-1 vent connector which allows for the use of polypropylene, CPVC or stainless steel venting. AMP-L is capable of up to 200 equivalent feet of vent in AL29-4C, polypropylene or CPVC. Modbus communication also comes standard.