Noritz NC1991-DVC Installation Manual

Also see for NC1991-DVC: Replacement Owner's guide Installation manual Owner's manual Owner's guide

Contents

Noritz NC1991-DVC Installation Manual Manual pdf 14 page image

14Gas MeterSelect a gas meter capable of supplying the entirebtuh demand of all gas appliances in the building.Gas Connection• Do not use piping with a diameter smaller thanthe inlet diameter of the water heater.• Gas flex lines are not recommended unlessthey are rated for 199,900 btuh.• Install a gas shutoff valve on the supply line.• Use only approved gas piping materials.Follow the instructions from the gas supplier.Gas PressureSize the gas line according to total btuh demandof the building and length from the meter orregulator so that the following supply pressuresare available even at maximum demand:Natural Gas Supply PressureMin. 4" WCMax. 10.5" WCLP Gas Supply PressureMin. 8" WCMax. 14" WC9. Gas PipingThe appliance and its individual shutoff valve must be disconnected from the gas supply piping systemduring any pressure testing of that system at test pressures in excess of 1⁄2 psig (3.5 kPa).The Appliance must be isolated from the gas supply piping system by closing its individual manualshutoff valve during any pressure testing of the gas supply piping system at test pressures equal to orless than 1⁄2 psig (3.5 kPa).The appliance and its gas connections must be leak tested before placing the appliance in operation.The inlet gas pressure must be within the range specified. This is for the purposes of input adjustment.In order to choose the proper size for the gas line, consult local codes or the National Fuel Gas CodeANSI Z223.1.Natural GasMeter **See next page for the pipe capacity charts.Noritz Tankless Gas Water Heater(199,900 Btuh)Clothes Dryer(35,000 Btuh)Barbecue(50,000 Btuh)Gas Range Stove(65,000 Btuh)10' (3m)10' (3m)10' (3m)10' (3m)5' (1.5m)5' (1.5m)5' (1.5m)5' (1.5m)Gas Fireplace(25,000 Btuh)Instructions1. Size each outlet branch starting from the furthestusing the Btuh required and the length from themeter.2. Size each section of the main line using thelength to the furthest outlet and the Btuhrequired by everything after that section.Sample Gas LineSample CalculationOutlet A: 45' (13.5m) (Use 50' (15m)), 50,000 Btuh requires 1/2"Outlet B: 40' (12m), 65,000 Btuh requires 1/2"Section 1: 45' (13.5m) (Use 50' (15m)), 115,000 Btuh requires 3/4"Outlet C: 30' (9m), 35,000 Btuh requires 1/2"Section 2: 45' (13.5m) (Use 50' (15m)), 150,000 Btuh requires 3/4"Outlet D: 25' (7.5m) (Use 30' (9m)), 25,000 Btuh requires 1/2"Section 3: 45' (13.5m) (Use 50' (15m)), 175,000 Btuh requires 1"Outlet E: 25' (7.5m) (Use 30' (9m)), 199,900 Btuh requires 3/4"Section 4: 45' (13.5m) (Use 50' (15m)), 374,900 Btuh requires 1-1/4"Section 3 Section 2 Section 1Outlet AOutlet BOutlet COutlet DOutlet E5' (1.5m)5' (1.5m)Section 4Measuring Gas PressureIn order to check the gas supply pressure to the unit, atap is provided on the gas inlet. Remove the hex headphilips screw from the tap, and connect a manometerusing a silicon tube.In order to check the gas manifold pressure, a pair oftaps are provided on the gas valve inside the unit.The pressure can be checked either by removing the hexhead philips screw and connecting a manometer with asilicon tube, or by removing the 1/8" NPT screw with anallen wrench and connecting the appropriate pressuregauge.