Raypak MVB 504A Installation & Operating Manual

Raypak MVB 504A Installation & Operating Manual Manual pdf 22 page image

22The MVB 504A-1504A heaters are wired for 120 VAC,12 amps while the MVB 2004A heaters are wired for120 VAC, 18 amps. Consult the wiring diagramshipped with the heater. Before starting the heater,check to ensure proper voltage to the heater andpump.Pumps must use a separate power supply and run thepower through the pump contactor, which is located inthe rear wiring box. Use appropriately-sized wire asdefined by NEC, CSA and/or local codes. All primarywiring should be 125% of minimum rating.If any of the original wire as supplied with the heatermust be replaced, it must be replaced with 105°C wireor its equivalent.All high voltage wiring connections to the MVB heaterare made inside the rear wiring box as shown inFig. 20. Power for indirect DHW pump not exceeding5 amps should be taken from terminals 4 (Hot), 5(Com), and 6 (Gnd). Power for system pump notexceeding 5 amps should be taken from terminals 7(Hot), 8 (Com), and 9 (Gnd). Power for boiler pumps3/4 HP and smaller should be taken from terminals 1(Hot), 2 (Com), and 3 (Gnd), and must be routedthrough the pump contactor; 30A supply is required.Power for pumps larger than 3/4 HP must be a sepa-rate circuit wired through the pump contactor. Powerto the MVB heater should be connected to terminals 1,2, and 3 as noted in Fig. 20. All low voltage wiring,including sensors, interlocks, enable/disable, and var-ious options are wired into terminals 1–24 on the frontwiring panel as noted in Fig. 25.Electrical Power ConnectionsInstallations must follow these codes:• National Electrical Code and any other national,state, provincial or local codes or regulations hav-ing jurisdiction.• Safety wiring must be NEC Class 1.• Heater must be electrically grounded as requiredby the NEC.• In Canada, CSA C22. 1 C.E.C. Part 1.Natural Gas – 1,000 BTU/ft3 , 0.60 specific gravity at 0.5 in. WC pressure drop•Propane Gas – 2,500 BTU/ft3 , 1.53 specific gravity at 0.6 in. WC pressure drop•Table I: Maximum Equivalent Pipe LengthNOTE: Manifold pressures should be ±0.2 in. WC.Table J: Manifold Gas Pressure SettingsModelNo.1 in. NPT 1-1/4 in. NPT 1-1/2 in. NPT 2 in. NPT 2-1/2 in. NPTN P N P N P N P N P504A 15 35 65 150 130 360754A 5 15 65 100 75 180 2501104A 35 55 35 90 125 300 3001504A 10 15 15 25 60 150 150 2752004A 35 90 85 210ModelManifold Gas Pressure SettingHigh Fire Values (in. WC)Natural Gas Propane Gas504A -4.1 -4.4754A -4.6 -5.81104A -4.6 -7.21504A -7.0 -9.22004A -4.4 -8.1