Bosch WR 250 -8 K..G Series User manual

with Hydropower Ignition
Gas Instantaneous Water Heaters
WR 250 -8 K..G..
WR 325 -8 K..G..
WR 400 -8 K..G..
Installation and perating Instructions
-THE APPLIANCE MAY ONLY BE INSTALLED BY AN AUTHORISED PERSON.
-Perfect functioning of the ppli nce is gu r nteed only if this specific tion nd the oper ting instructions re followed.
-The customer sh ll be provided with these inst ll tion instructions.
-The fitter sh ll expl in the function nd oper tion of the ppli nce to the customer.
-Servicing m y only be c rried out by uthorised personnel.
-Inst ll tion in m rine environment should be voided.
-Inst ll in ccord nce with AS5601, AS/NZS3500.4.2, NZS5261 nd ll loc l building, w ter nd g s fitting regul tions.
-Not suit ble for pool or SPA pplic tion.
-F ilure to inst ll the ppli nce in ccord nce with these inst ll tion instructions m y void w rr nty.
6 720 606 692 (02.05) JS
Approved for indoor inst ll tion only.
For your safety
If you smell gas:
1. Close gas isolating cock
2. pen windows
3. Do not actuate any electrical switches
4. Extinguish naked flames
5. Contact gas authorities immediately
Do not store or use fl mm ble m teri ls or liquids
ne r the ppli nce.
Do not pl ce rticles on or g inst this ppli nce.

26 720 606 692 (02.05)
W Multipoint g s w ter he ter
R Autom tic power d ption
250 Code number 17,5 kW (250 kc l/min)
325 Code number 22,75 kW (325 kc l/min)
400 Code number 28 kW (400 kc l/min)
-8 Version code number
K Chimney flue
V Connector
1 Temper ture selector
G Hydropower ignition
23 G s code number, n tur l g s H
32 G s code number, LP g s
S2405 Austr li n Execution
P ge
Index
1. Description of Appliances ......................................... 2
1.1 Equipment ....................................................................... 2
1.2 Type Overview ................................................................ 2
1.3 Connecting Me surements .........................................3
1.4 Construction l Det ils .................................................. 3
1.5 Wiring Di gr m .............................................................. 4
2. Technical Data ..................................................................... 4
3. Installation ............................................................................. 5
3.1 Gener l Rem rks .......................................................... 5
3.2 Loc tion ........................................................................... 5
3.3 Connecting Appli nce .................................................. 5
3.4 Remov l of Front Shell ................................................ 5
3.5 W ter Supply ..................................................................5
3.6 G s Connection ............................................................5
3.7 Flue ................................................................................... 5
3.8 Commissioning ............................................................... 5
3.9 HDG Functioning ..........................................................5
4. Servicing ................................................................................ 5
4.1 Setting Appli nce .......................................................... 5
4.2 G s djustments ...........................................................5
4.3 Conversion to Other G ses........................................ 6
4.4 M inten nce ................................................................... 6
4.5 F ult Finding ................................................................... 7
5. perating Guide - Quick Reference ......................... 8
1.2 Type verview
P ge
1. Description of Appliances
Multipoint g s w ter he ters with hydropower ignition nd
built-in dr ught diverters for flued connection.
White pl stic-co ted front c sing.
Autom tic g s d ption by me ns of continuous g s control.
Suit ble for sm ll nd l rge hot w ter consumption.
1.1 Equipment
- fully protected with sensor electrode fl me f ilure device;
- hydropower ignition;
- utom tic power d ption;
- temper ture limiter in power circuit;
- dr ught diverter.
W R 250 - 8 K V 1 G 23
32 S 2405
W R 325 - 8 K V 1 G 23
32 S 2405
W R 400 - 8 K V 1 G 23
32 S 2405

36 720 606 692 (02.05)
1.4 Constructional Details
1.3 Connecting Measurements
1 Front cover
2 G s control slide
3 W ter flow selector
4 G s connection
5 Dr ught diverter
6 Chimney with
dr ught diverter
7 He t exch nger
8 G s v lve ssembly
9 Ignition unit
10 W ter v lve
ssembly
11 Led f ilure indic tor
12 Led indic tor m in
burner condition
1 Pilot burner
2 Sp rking plug
3 Sensor electrode
4 He t exch nger
5 Burner
6 Injector nozzle
7 Me suring point (burner)
7b Me suring point (inlet g s)
8 Hydrogener tor
9 M in g s v lve
10 Di phr gm (g s)
11 Pilot g s v lve
12 Servo v lve
13 Slow ignition v lve
14 Venturi
15 G s inlet
16 W ter v lve
17 Correcting screw for min.
w ter flow
18 W ter flow selector
19 Switch
20 W ter governor
21 W ter filter
22 Di phr gm (w ter)
23 Cold w ter connecting pipe
24 Hot w ter connecting pipe
25 Ignition unit
26 G s control slide
27 Poppet v lve he d
28 Pilot g s pipe
29 Temper ture limiter
Diagram 1
Diagram 2
Dimensions ABC
D
EFG
(mm) LPG NG
WR 250-8 KG 360 680 228 115 462 162 25 R1/2" R3/4"
WR 350-8 KG 400 755 228 140 500 196 30 R1/2" R3/4"
WR 400-8 KG 460 755 334 140 530 166 30 R1/2" R3/4"
H

46 720 606 692 (02.05)
2. Technical Data
1.5 Wiring Diagram
Diagram 3
1 - Servo g s v lve
2 - Membr ne v lve
3 - Pilot g s v lve
4 - Sensor electrode
5 - Sp rking plug
6 - Temper ture limiter
7 - Ignition unit
8 - Hydrogener tor
9 - Switch
10 - Led f ilure indic tor
11 - Led indic tor m in burner condition
Appliance Ratings WR 250 - 8... WR 325 - 8... WR 400 - 8...
Rated output MJ/h (kW) 63 (17,5) 82 (22.75) 101 (28)
Rated input MJ/h (kW) 79 (22,0) 104 (29,0) 127 (35,3)
Gas inlet pressures
Natural gas kPa (mbar) 1,11 (11,1) 1,11 (11,1) 1,11 (11,1)
LP gases kPa (mbar) 2,75 (27,5) 2,75 (27,5) 2,75 (27,5)
Gas consumption
(based on gross c.v. at 15°C/60°F - 1013 mbar - dry
Natural gas
(10,5 kWh/m3- 9000 kcal/m3- 37,8 MJ/m³) m³/h 2,1 2,8 3,4
LP gas
(13,8 kWh/m3- 11800 kcal/m3- 49,6 MJ/kg) kg/h 1,6 2,1 2,6
Water data
Max. water flow l/min. 10 13 16
Temperature rise °C25 25 25
Min. inlet water pressure bar 0.6 1,0 1,3
kPa 60 100 130
Min. water flow l/min. 222
Temperature rise °C50 50 50
Min. inlet water pressure bar 0,3 0,4 0,5
kPa 30 40 50
Burner pressure for maximum output
Natural gas kPa (mbar) 0,89 (8,9) 0,84 (8,4) 0,78 (7,8)
LP gases kPa (mbar) 2,60 (26,0) 2,60 (26,0) 2,60 (26,0)
Burner pressure for minimum output
Natural gas kPa (mbar) 0,15 - 0,25 (1,5 - 2,5) 0,15 - 0,25 (1,5 - 2,5) 0,15 - 0,25 (1,5 - 2,5)
LP gases kPa (mbar) 0,35 - 0,65 (3,5 - 6,5) 0,35 - 0,65 (3,5 - 6,5) 0,35 - 0,65 (3,5 - 6,5)
Main burner injectors
Natural gas Ømm 1,20 1,30 1,30
LP gases Ømm 0,75 0,79 0,76
Pilot burner injector
Natural gas (Identity nr.) 19 19 19
LP gases (Identity nr.) 74 74 74

56 720 606 692 (02.05)
3. Installation
Install in accordance with AS5601, AS/NZS3500.4.2,
NZS5261 and all local building, water and gas fitting regu-
lations.
3.1 General Remarks
Any loc l by-l ws nd regul tions pert ining to inst ll tion
nd use of g s-he ted ppli nces must be observed.
3.2 Location
The ppli nce should be inst lled in frost-protected, well
ventil ted room, s ne r s possible to the most frequently
used t p. In order to prevent corrosion, m ke sure th t the
combustion ir is kept free of ggressive subst nces.
Subst nces th t especi lly contribute to corrosion re
h logen ted hydroc rbons (e.g chlorine, fluorine), which re
cont ined in solvents, p int, dhesives, propell nt g ses,
v rious household cle ners, etc.
Cupboard-like Enclosures
Note: Ventil tion requirements s per AS5601.
Minimum v lues:
A ≥10 cm
B ≥40 cm
C ≥30 cm
Diagram 4
G661_014
3.3 Connecting Appliance
Secure he ter to the w ll using the two mounting br ckets
supplied.
3.4 Removal of Front Shell
Remove ret ining nut (below g s slide). Swing the c sing
to the front nd push upw rds.
3.5 Water Supply
Pipes of suit ble bore ccording to loc l conditions nd in
compli nce with pertinent regul tions to be used.
Cold w ter inlet (right) nd hot w ter outlet (left) re m rked
by rrows on the w ter v lve housing.
Use only G te V lve or Full Flow B ll V lve. Non-Return
V lves MUST NOT BE USED.
Cold w ter - flush ll lines prior to connection.
M ke sure w ter filter is fitted to inlet point of w ter v lve.
Fit inline w ter str iner where ppropri te.
3.6 Gas connection
Size g s supply pipe s per AS5601. Note: in dequ te pipe
sizing m y void the w rr nty.
3.7 Flue
Use pproved single or twin skin flue in ccord nce with
AS5601.
3.8 Commissioning
Purge g s piping of ir. Tr pped ir c n result in the pilot
burner f iling to light within 30-40 seconds. In th t c se,
turn off the hot w ter t p nd then turn it on g in. This
rest rts the ignition cycle.
3.9 HDG Functioning
HDG is loc ted in the w ter circuit, between the w ter v lve
nd the he t exch nger. The HDG h s turbine, which
turns with the w ter flow. This movement is tr nsmitted to
n electric gener tor, which supplies the electronic box.
The electric volt ge supplied by the HDG is v lue between
1,1 nd 1,7 V DC. With the HDG, the use of b tteries is no
longer necess ry.
4. Servicing
4.1 Setting Appliance
All he ters re djusted before le ving the f ctory. LPG g s
he ters re djusted for 2,75 kP nd N tur l g s he ters
for 1,11 kP .
Note: M ke sure th t the ppli nce is suit ble for the type
of g s v il ble t the inst ll tion.
4.2 Gas adjustments
Gas burner pressure adjustment for maximum
output
1. Turn off g s supply.
2. Loosen se ling screw D (di gr m 5) nd connect U
tube m nometer.
3. Turn on g s supply nd st rt up ppli nce in ccord nce
with oper ting instructions. Fully open hot w ter t p.
4. Check th t burner pressure is s st ted on the r ting
l bel.
5. If other th n specified test inlet pressure. Turn off g s
supply, remove m nometer, tighten se ling screw, turn
on g s supply nd test for le ks.

66 720 606 692 (02.05)
4.4 Maintenance
When it has been in service for a year, the appliance
should be inspected, thoroughly cleaned and, if
necessary, descaled.
Servicing m y only be c rried out by n uthorised person.
Before c rrying out m inten nce work of ny kind, the g s
nd cold w ter isol ting cocks must be turned off.
Heat Exchanger body
Cle n the flue side of the he t exch nger block. Check
he t exch nger body nd connecting pipes for sc le nd if
necess ry desc le with propriet ry desc ler ccording to
m nuf cturers instructions.
The desc ling is done only to the he t exch nger, the
chemic ls used d m ge the HDG nd other p rts.
Test for le ks t m x. 2000 kP .
Use new g sket when re- ssembling.
Burner
Unscrew burner nd cle n in so p solution if necess ry.
Pilot burner
The fl me should he t the fl me-f ilure electrode (di gr m
3, item 4). If the fl me is too sm ll, cle n pilot burner.
Slow ignition valve
After unscrewing the v lve, cle n out ny dirty p rticles.
The b ll inside the v lve must move freely (check by sh king).
Inspect the O-ring nd repl ce if necess ry. Screw the slow
ignition v lve b ck in. Check ll connections for le ks.
Checking the vacuum chamber
- Push the sliding g s control to the right nd dr w off hot
w ter.
- Disconnect green le d from the servo g s v lve (di gr m
3, item 1). The m in burner should go out nd the pilot
burner rem ins lit. Disconnect the red le d from the pilot
g s v lve (di gr m 3, item 3) - the pilot fl me should
then go out.
- Re-connect red le d, pilot burner should re-ignite.
- Re-connect green le d, m in burner should re-ignite.
Functional Test (does not pply to first time commissioning).
Switch off ppli nce. When hot w ter t p is turned on,
the burner should come on full within 5 seconds. When the
hot w ter t p is turned off, the burner should go out within
pproxim tely 2 seconds.
Diagram 7
G661_009
G661_016
Diagram 6
4.3 Conversion to ther Gases
nly use conversion kits supplied by the manufacturer.
This oper tion must be c rried out by qu lified fitter.
1. Cut off the g s supply by closing the g s isol ting v lve,
nd remove the front cover of the ppli nce;
2. Remove the burner nd repl ce the injectors (di gr m 7,
item 1);
3. Repl ce the pilot g s injector (di g. 7, item 3);
4. Repl ce the v cuum ch mber if converting from LP to
NG. Pressure regul tor lso required.
5. Repl ce the m in poppet v lve he d (di g.2, item 27);
6. Tighten the g s v lve nd check for possible le ks;
7. Note the new type of g s on the ppli nce's r ting pl te;
8. Fin lly, djust the minimum g s flow of the ppli nce
using suit ble method, the most common one being
described below:
) Select m nometer with mb r or mm (H2O) sc le;
b) Loosen se ling screw D in the burner pressure t p-off
point (di gr m 5) nd connect the m nometer;
c) Open the g s isol ting v lve;
d) St rt up the ppli nce with the output slide control t
the minimum output position;
e) Adjust the pressure using screw C (di gr m 6), in
compli nce with Section 2 Technic l D t , p ge 4.
G662_042
Diagram 5
Gas burner pressure adjustment for minimum output
(see clause 4.3, section 8)
Gas inlet pressure adjustment
1. Turn off g s supply.
2. Remove inlet test point screw A.
3. Att ch U tube m nometer.
4. Turn on g s supply nd st rt up ppli nce in ccord nce
with oper ting instructions.
5. Check inlet g s pressure while ppli nce is oper ting.
6. For n tur l g s ppli nces djust pressure t ppli nce
regul tor.
No djustment for LP ppli nces, check cylinder
regul tor nd pipe size.
7. Turn off g s supply, remove m nometer, repl ce se ling
screw, turn on g s supply nd test for le ks.

76 720 606 692 (02.05)
4.5 Fault Finding
The following t ble outlines some common problems nd their solutions.
Frost Protection
In re s where the tmospheric temper ture drops below
0°C, the he ter must be dr ined to prevent d m ge due to
the exp nsion of freezing w ter.
Re-commissioning after repairs to the gas supply
Purge g s piping of ir. Tr pped ir c n result in the pilot
burner f iling to light within 30-40 seconds. In th t c se,
turn off the hot w ter t p nd then turn it on g in. This
rest rts the ignition cycle.
Problem Cause Solution
Appli nce does not light. Switch in "off" position. Put it in the "on" position.
Pilot solenoid. Repl ce solenoid.
Over temper ture switch. Repl ce switch.
No power to pilot solenoid. Repl ce ICU.
Pilot lights but no m in burner. Slide control set to off. Turn control to on.
M in solenoid open circuit. Repl ce solenoid.
Smell of g s. Luminous fl me. Cle n burner.
Loose g s connection. Loc te le k with so p solution.
Yellow fl me. Burner venturi blocked. Cle n with venturi brush.
W ter le k on top of w ter v lve lid. D m ged O ring. Repl ce O ring, gre se with Unisilkon
L641# 8709918413.
Excessive pressure. Check w ter isol ting v lve. (Must be g te
v lve or simil r).
Frost d m ge. Dr in ppli nce or fit Exogel exp nsion
v lve # H707060151.
No v ri tion in w ter flow r te. D m ged selector sh ft. Repl ce sh ft.
Excessive w ter pressure. Check w ter supply pressure.
Low burner fl me, w ter does not he t
up.
Low inlet g s pressure. Check supply regul tor nd pipe size.
L.P.G. ppli nces - Check if g s cont iner
freezes while in use. If so, pl ce it in
w rmer loc tion.
Low burner pressure. Check ppli nce regul tor.
Low w ter flow. Check w ter flow r te.
Low fl me. Move slide control to high.
Low w ter temper ture. W ter flow selector set in w rm
position.
Set flow r te to individu l need.
Low g s pressure. Check pressure.
Cross connection. Disconnect hot outlet with cold off.
Correct connection.
Low w ter flow. Low w ter pressure. Check nd djust.
Blocked w ter v lve. Cle n filter.
Blocked he t exch nger. Desc le.
Blocked shower rose or t p er tor. Cle n.
Slow Ignition sp rk. F ulty over temper ture switch. Repl ce switch.
No sp rk. F ulty ICU. Repl ce ICU.
F ulty fl me sensing rod. Repl ce fl me sensing rod.
Pilot burner h rd to ignite. Insufficient w ter pressure. Check nd djust.
Red led fl shing.
M in burners go out during hot w ter
use.
Temper ture limiter ctiv ted. Re-ignite the ppli nce 10 minutes l ter. If
it h ppens g in, cont ct your service
person.

86 720 606 692 (02.05)
5. perating Guide - Quick Reference
Purge all water and gas pipes before operating.
Turn off all water taps before adjusting appliance.
Warning - If the ppli nce does not oper te, burns with yellow fl me, le ks w ter or g s smell is evident, turn
off nd cont ct the loc l g s uthority, the m nuf cturer or n uthorised service person.
When ttempting to light the ppli nce ensure th t ll hot w ter t ps re turned off.
Starting and shutting off the appliance
G661_004
G669_097
G085_259 G085_259
G861_189
Temperature regulation
Turn nti-clockwise
W ter flow decre ses,
temper ture incre ses.
Turn clockwise
W ter flow incre ses,
temper ture diminishes
utput control
output
incre se
output
decre se
Red light fl shing:
check w ter pressure
Green light on= M in burner on
Green light off= M in burner off
To shut off the ppli nce, turn the
on/off switch to position "0"
To switch the ppli nce, turn the
on/off switch to position "1"

Warranty Details
Your Bosch Hot W ter Unit is gu r nteed s follows:
For ppli nces used in domestic pplic tions, ie. norm l hot w ter dr wn from household outlets, the w rr nty period is
One (1) ye rs p rts nd l bour. Addition lly, the he t exch nger is covered for period of ten (10) ye rs (p rts only).
For ppli nces used in commerci l pplic tions the w rr nty period is Six (6) months p rts nd l bour including the he t
exch nger.
The w rr nty period commences from the purch se d te. Cl ims for w rr nty will only be ccepted upon suit ble proof of
purch se submitted to Robert Bosch (Austr li ) Pty. Ltd. or n pproved Bosch Service Agent uthorised to c rry out
w rr nty rep irs.
PURCHASER’S STATUT RY RIGHTS
The w rr nty terms set out below do not exclude ny conditions or w rr nties which m y be m nd tory implied by l w, nd
your ttention is dr wn to the provisions of the Tr de Pr ctices Act, 1974, nd St te legisl tion which confers cert in rights
upon consumers. The ROBERT BOSCH (AUSTRALIA) PTY. LTD. W rr nty supplements these.
EXTRACT F TERMS F DELIVERY AND SALE:
W rr nty of products m rketed by Robert Bosch (Austr li ) Pty. Ltd. herein referred to s RBAU.
) RBAU w rr nts products m rketed by it s free from f ults nd defects nd h ving the specified qu lities ccording
to the respective st te of technology. Notwithst nding th t the products m y h ve been sold by description or s mple
the products sh ll be ccepted by the Buyer even though lter tions in design or construction h ve been gener lly
introduced between the d te of contr ct nd the delivery of the products.
b) The w rr nty sh ll be limited to the repl cement or rep ir t the option of RBAU of ny defective products nd of such
p rts of RBAU’s products s h ve been d m ged in consequence of the defect despite proper tre tment. P rts
repl ced will not be returned.
c) i) Rep irs nd m inten nce sh ll not extend the w rr nty period of the ppli nce.
ii) If the product is loc ted outside of the service gent’s re , the consumer sh ll be responsible for the service
gent’s tr velling costs, nd if necess ry the expenses of freight, p cking nd ch rges of simil r n ture.
Without limiting the gener lity of these terms of delivery this w rr nty sh ll not pply to products sold in the following
c ses :—-
i) if the products sold re rep ired or ltered by ny third p rty without RBAU’s consent.
ii) where p rts not m nuf ctured or sold by RBAU re used in nd repl cement or rep ir.
iii) if products re not used with proper c re nd for the purpose for which they re sold nd in ccord nce with ny
specified instruction for use.
iv) if ch nges occur in the condition or oper tion l qu lities of the products due to incorrect stor ge or mounting or due
to clim tic or other influences.
v) in respect of f ulty construction or defects due to the use of unsuit ble m teri ls if such method of construction or
use of m teri l h s been specified by the Buyer.
vi) in respect of surf ce co ting nd gl ss d m ge.
vii) in respect of the repl cement of p rts when such repl cements re p rt of the norm l m inten nce, service or norm l
we r nd te r.
No serv nt or uthorised service gent h s uthority to dd to or lter the terms of this w rr nty.
PLEASE N TE:- If a service call is requested and it is found that it is not a manufacturing fault, you may be charged
for the call even during the warranty period.
ROBERT BOSCH (AUSTRALIA) PTY LTD
(Incorpor ted in Victori ) Phone [phone]
Melbourne
57-63 McN ughton Ro d Cl yton
Victori 3168
Phone [phone]
F x [phone]
S les Hot line: 1300 30 70 37
S les F x: 1300 30 70 38
www.bosch.com. u
New Zealand
14-16 Constell tion Drive,
M ir ngi B y,
Auckl nd 1310
S les Hotline [phone]