Ring No. 1Optimum Working Pressure: 0.5 psig/35mbarConsumption Per Hour: 0.820 KGSRated Heat Output: 36000 BTU/HR Ring No. 2Optimum Working Pressure: 0.5 psig/35mbarConsumption Per Hour:1.270 KGSRated Heat Output: 56000 BTU/HR Ring No. 3 Optimum Working Pressure: 0.5 psig/35mbarConsumption Per Hour:1.730 KGSRated Heat Output: 76000