Bosch Model GWH 425 manual

GWH 425 PN INDOOR MODEL Flow Modulate d with St anding pilot Suit able for heating pot able wat er only - Not approved for spac e heating purpose s (Intended for variable flow applications with steady cold water inlet temperatures) GWH- 425-PN-N GWH- 425-PN-L 6 720 608 034 U S (06.05 ) AL Warning: If the informatio n in this manu al is not followed[...]

6 720 608 034 2 Index Index 1 Warning 2 2 Appliance d etails 3 2.1 GWH 425 PN specifications (Tech nical data) 3 2.2 Unpacking the GWH 425 PN hea ter 4 2.3 General rules to follow for safe ope ration 4 2.4 Dimensions an d installation clea rances 5 3 Installation instructions 6 3.1 Introduction 6 3.2 Proper location for installing you r heater 6 3.[...]

6 720 608 034 Appliance detai ls 3 2 Applian ce details 2.1 GWH 425 PN specifications (Technical data) Approved in US/Canada Capacity GWH 425 PN: 4.3 GPM Maximum out put GWH 425 PN: 91 525 Btu/hr Maximum in put GWH 425 PN: 117 000 Btu/hr Efficiency in % Recovery effic iency 78% Min. Output GWH 425 PN: 23 906 Btu/hr Gas Requi rement Gas connecti on [...]

6 720 608 034 4 Appliance de tails 2.2 Unpacking the GWH 425 P N heater This heater is p acked securely. Before installing the unit, be certain you have the correct heater for your type of Gas - Propane or Natural Gas. Ide ntification labels are found on the shipping box, and on the rating p late which is located on the right side panel of the cove[...]

6 720 608 034 Appliance detai ls 5 2.4 Dimensions and installation clearances Fig. 3 Dimensions in Inches and (mm ) 4 Heat exc hanger 5 Burner 10 Tempe rature cont rol 11 Water valve 20 Gas con nection 26 Outpu t control 36 Front cover 37 Hole f or fixing to wall 38 Exhau st pipe to w all 39 Draught diverter w ith flue g as monitor 40 Gas val ve 49[...]

6 720 608 034 6 Installation instructions 3 Installa tion instru ctions 3.1 Introduction Please follow t hese instru ctions. Fa ilure to follow instructions may result in: B Damage or injury . B Improper operati on. B Loss of warrant y. If you are unable to perform the tasks re quired to install this heater properly, please contact a locally licens[...]

6 720 608 034 Installation instructions 7 3.4 Mounting Heater Remove cov er and inspect. B Remove the temp erature control. B Unscrew the c over fixing screws, see Fig. 6. B Remove the ou ter case by sliding it forwards and then lifting upwar ds. B Ensure that the flue terminal is clea r. B After inspection , replace front cover and tighten screws.[...]

6 720 608 034 8 Installation instructions 3.5 Combustion air requirements The BOSCH PRO wate r hea ter holds cold water in its copper heat exchanger and water valve when n ot in u se. Because of th is, any cold air that comes down through the unit's vent p ipe is capable of freezing these components. Thi s Installation Manual spec ifies the mi[...]

6 720 608 034 Installation instructions 9 3.6 Venting B Minimum vent p ipe diameter: 5 inch es B Minimum vertic al vent height: 6 fee t, with no elbows B Establish 12 in ch rise before any e lbow The heater mu st be vented to t he ou tside following a ll local ordinanc es and spe cifications for installin g a gas appliance vent or chimney. Th e hea[...]

6 720 608 034 10 Installation instructions Masonry chim ney Masonry chimne ys shal l be built and install ed i n accordance with NFPS 211 or local codes. A minimum 5" diameter gas ven t pi pe (me tal do uble wall T ype B), or an approve d clay flue lin er or a listed c himney lining system must be used when ve nting into a naturally drafting, [...]

6 720 608 034 Installation instructions 11 3.7 Gas piping & connections Before connecting the gas supply, check the rating plate on the right side of the he ater to b e sure that the heater is rated for the same gas to which it will be connected. In the United States: The installation must conform with local codes or, in the absence of loc al c[...]

6 720 608 034 12 Installation instructions FOR NA TU R AL GAS Maximum Cap acity of pipe in Cubi c Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and a Pressure drop of 0.3 in Wate r Column (0.75mb ar).(Based on a 0.6 0 Specific Gravity Gas) Btu numbers given in thousands. Cop per tubing is prohi bited for use w ith Natural Gas in the C o[...]

6 720 608 034 Installation instructions 13 3.8 Measuring gas pressure Connectin g manometer B Shut off gas. B Remove front cover and locate inlet gas pressure measuring point o n the right side, se e Fig. 15. B Loosen screw from test point o n the right side and connect manome ter tube on test poin t. Fig. 15 G as pressure mea suring point A Inlet [...]

6 720 608 034 14 Operation inst ructions 3.10 Recirculation application Since recirculation through the h eater is not permissible, the following drawing is provided t o outline a p roper recirculation application using the BOSCH PRO water heat er wi th an Ariston minitan k. Th is schematic is for illustrati on o nly and mu st not be used for actua[...]

6 720 608 034 Operation inst ructions 15 4.2 Lighting instructions B STOP! Read t he previous safety infor mation. B The gas valve must be turned off b y sliding the gas valve button to all the way to the le ft. Fig. 18 B Wait five (5 ) minutes t o clear ou t any gas. If you smell gas, STOP! Follow “B” in chap ter 4.1. If you don’t smell gas,[...]

6 720 608 034 16 Operation inst ructions 4.4 Setting the water temperature The GWH 425 P N has a gas control that modulates burner input in response t o flow. Its purp ose is to ensure that t he ho t wa ter temperature will rem ain steady, a lthough the wa ter flow demand might vary. The output temperature can be adjusted with eith er the temperatu[...]

6 720 608 034 Maintenance a nd service 17 5 Mainten ance and servic e 5.1 Maintenance intervals The GWH 425 PN requires periodic maintenance. The below time ma intenance interva ls should kept the un it operating for m any years. Every year B Inspect inlet w ater filter screen ( 5 .2) B Inspect pilot as sembly and flame ( 5.3) B Inspect burner a ss[...]

6 720 608 034 18 Maintenance and service 5.4 Main burners The ma in burn er fl ames shou ld be blue, w ith a more intense blue c one in the center core. Ye llow flames could be a sign of wrong size gas orifices or dirty burners, a block age on the heat exchangers fins. If some b urners have yellow flames whil e others have blu e flames, it is li ke[...]

6 720 608 034 Troubleshooti ng 19 6 Troubles hooting 6.1 Introduction Many of the q uestions custome rs ask regarding operation of this uni t can be a nswered b y following t he troubleshoot ing steps as outlined below . Visit our w eb site at www.boschpro.c om for more d etailed troubleshoot ing. F or best results, perform each step before proceed[...]

6 720 608 034 20 Troubleshoot ing 6. Verify pilot f lame completely engulfs the thermocoupl e tip. If pilot is too small, cl ean pilot orifice (see chapter 5. 3). 7. If the water has a high mineral con tent, t he h eat exchanger may be scaled internally. T his restri cts th e water path , causing the water to over h eat which shuts all gas off to t[...]

6 720 608 034 Troubleshooti ng 21 6.7 Water is too hot 1. Verify gas type indi cated in rating sticker located on right-hand side of cover, coincides with t he gas typ e you are usin g. NG is a na tural gas unit and L P is for liquid propan e. 2. Adju st the gas control slide b utton fro m three flame position towards the one flame posi tion for co[...]

6 720 608 034 22 Troubleshoot ing the way cl ockwise, the flow rate should b e close to 2gpm, filli ng the jug in 15 seconds. With the temperature adjustment kn ob set all the way counterclockwi se, the flow rate should be close to 4gpm, fillin g the jug i n 7 second s. If the fl ow rate is n ot adequate, i nspect and c lean the inlet filter scre e[...]

6 720 608 034 Protecting t he environment 23 7 Protectin g the en vironmen t Packing The p acking box may be fully re cycled as confirmed by the recyclin g symbol . Componen ts Many parts in th e heater can be fully recycled in the end of the produ ct li fe. Contact your city authorities for information ab out the disposal of recyclable produ cts. [...]

6 720 608 034 24 Interior compon ents and diagr am parts list 8 Interior compone nts and diagram parts list 8.1 I nterior components Fig. 28 F unctional scheme 4 Heat exc hanger 5 Burner 10 Tempe rature adju stment sel ector 11 Water valve 20 Gas con nection 22 Flexibl e hot outlet 26 Gas con trol slid e 30 Pilot g as tubing 102 Piezo[...]

6 720 608 034 Interior compon ents and diagr am parts list 25 8.2 Components diagram Fig. 29 C omponents Diag ram 43 50 49 32 48 46 45 28 29 30 31 25 17 18 19 20 21 23 26 24 27 33 34 35 13 36 37 22 38 39 40 41 42 44 47 8 9 11 12 13 14 15 16 10 6 4 5 51 1 2 3 7 672 060 8126 -02.1 JF 52[...]

6 720 608 034 26 Interior compon ents and diagr am parts list 8.3 Par ts list Item Description R eference 1 Front cover 8 705 431 246 0 2 Shield 8 705 506 817 0 3 Temp control knob 8 702 000 295 0 4 Draft Diverter 8 705 505 442 0 5 Exhaust pipe union Ø128 8 705 504 046 0 6 Angle bracket 8 708 003 192 0 7 Trade mark badge 8 701 103 135 0 8 Heat exc[...]

6 720 608 034 Fifteen Y ear Limited Warrant y 27 9 Fifteen Year Lim ited War ranty General BOSCH PRO wa ter heaters are warra nted by t he Manufactur er (BOSCH ) through BBT North Americ a. BBT North America (BBTNA) w ill furnish a repl acement heat excha nger and will fu rnish a replacement of any other part which fail s in no rmal use and service[...]

Recycled pape r © 200 6 B BT NO RTH AM E R I CA CO R P O RA TI O N, W aitsf ield, V T all rights rese rved VU L CANO T ermodomésticos S.A . Estrada de C acia 38 0 1 - 85 6 Aveiro - PO RTUG AL BBT NORTH AMERICA Bosch Group Bosch Water Heating 340 Mad River Park Waitsfield, VT 05673 Phone 866-330-2730 Fax 802-496-6924 www.boschpro.com techsupport@b[...]