520 HN. Warning: If the information in this manual is not followed exactly, a fire or explosion may . 10 LIFETIME LIMITED WARRANTY FOR BOSCH TANKLESS .. Gas types. Natural Gas. LP Gas. Venting. Natural Draft. Vent diameter inches. View and Download Bosch 520-HN-N user instructions online. Water Heater Bosch 520-PN-N Operation Manual Water Heater Bosch 250SX LP Manual. Bosch Therm 7703431996; 520 HN LP; Liquid Propane Tankless water Part Number, Model # on unit (Labeled Engraved) See Receipt Box Catalog or Manual Bosch | 520 HN LP | Tankless water heaters | Liquid propane | ResidentialTroubleshoot Therm 520 HN Consult powervent manual for more details. – a. NG is a natural gas unit and; LP is for liquid propane (See chapter 2.2). 2. Bosch installation guide and manuals. BoschTherm 520PN, Formerly GWH 425 PN. GL4Ti · Bosch Therm 520 HN, Formerly GWH 425 HN. GL8Ti. 21. Marz 2016 Verify gas supply is on at Natural Gas meter or Propane Tank. Make sure all manual gas shut off valves are in the open position. Have licensed gas technician Browse Bosch Gwh 520 Hn Natural Gas Tankless Water Heater owner's manuals, user guides, instructional help documents & operating information to learn View and Download Bosch 520-HN -L manual online. Page 19 Installation instructions | 19 FOR LP GAS Maximum Capatity of Pipe in Thousands of BTU per