Bosch C 1050 Manual

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Installation instructions11
Fig. 8 Concentric vent kit example 
3.3.2 Vent specifications 
Establish  vent  clearances  that  comply  with  the  vent 
manufacturers  specifications  and  all  applicable
national/local codes. Venting specifications
*
ULC S636-95, UL1738 certified
Condensate drain requirements 
An  external  condensate  drain  (not  supplied  with  the 
heater)  must  be  installed  under  the  following
conditions: 
• All vertical terminating vent installations. 
• Horizontal  terminating  vent  installations  where  th e
total linear vent length is greater than 6 feet (1. 8 m).
• Vent  installations  where  any  section  of  the  exhaus t
vent pipe passes through an unconditioned space.
Minimum combustion air and exhaust pipe  
length 
The  minimum  exhaust  pipe  length  is  1  foot  (0.3m)  of 
straight  vent  pipe.  The  minimum  combustion  air  pipe
length is one 90 ° elbow.
DescriptionLength
Kit part no. 
and quantity
196016
3- In. Rain Cap N/A 1 
4- In. Diameter SDR-26  
Pipe 24 In. long 1
3- In. Y 
Concentric Fitting N/A 1
2- ½ In. Diameter SDR-
26 Pipe 37-1/8 in. 
long 1
3- In. Condensate drain 
Tee N/A 1
1.5- In. Condensate drain 
bushing N/A 1
Table 3 Concentric vent part breakdown
6720608836-27.2V
3 (76mm) 
3 (76mm)
INTAKE
EXHAUST
COMBUSTION  
AIR
MAINTAIN 12 IN. (18 IN. FOR CANADA) 
MINIMUM CLEARANCE ABOVE  
HIGHEST ANTICIPATED SNOW LEVEL.  
MAXIMUM OF 24 IN. ABOVE ROOF.
EXHAUST
ROOF BOOT/
FLASHING (FIELD 
SUPPLIED
DRAIN TEE
(196278)
CONCENTRIC  
VENT KIT 
(196016)
Diam.Aproved terminals
E x
h a
u s t  3 or 4 inches “T” terminal
90 ° elbow
PVC Flue Cap* (ECAP321)
Vertical terminations only 3 diameter only
Concentric
(196016)
I
n t
a k 
e  3 or 4 inches “T” terminal
90 ° elbow
PVC Flue Cap* (ECAP321)
Vertical & horizontal terminations approved 3 diameter only
Concentric 
(196016)
Table 4 Venting specifications for intake and exhaus t 
						

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Installation instructions 
Maximum combustion air and exhaust pipe  
length 
The  following  tables  display  the  maximum  allowable 
straight  pipe  lengths  for  combustion  air  and  exhaus
t
piping  with  consideration  to  the  number  of  elbows
used.  Reduce  the  equivalent  length  for  each  elbow
used from the maximum allowable length depending on
the  system  used.  Refer  to  table 5  if  using  3  diamet er
venting. Refer to table 6 if using 4 diameter venti ng.Use of elbows 
It is recommended to limit the amount of elbows use
d in 
the exhaust and combustion air piping to reduce fri ction 
in the air flow.  The following lists the maximum a mount 
of 90° elbows allowed in either the exhaust or comb us-
tion air piping:
3  
VentingMaximum  
allowable  
Exhaust 
pipe lengthMaximum  
allowable  
Combustion  
air pipe 
lengthElbow  
Equivalency
90°45°
Twin pipe  
system
31ft 31ft 5 ft 3 ft
Concen- 
tric system23ft 23ft 5 ft 3 ft
Table 5 Maximum Allowable Exhaust and Combustion  Air Lengths for 3 venting
4  
VentingMaximum  
allowable  
Exhaust 
pipe lengthMaximum  
allowable  
Combustion  
air pipe 
lengthElbow  
Equivalency
90°45°
Twin pipe  
system
63ft 63ft2.5ft 1.5ft
Concen- 
tric system43ft 43ft2.5ft 1.5ft
Table 6 Maximum Allowable Exhaust and Combustion  Air Lengths for 4 venting
Max. number of 90 °  
elbows3 
venting4 
venting
Twin pipe system 5 7 
Concentric system 4 7
Table 7
i
Two 45° elbows are equal to one 90°  
elbow. Any combination of 45° and 
90° elbows may be used in the vent 
system as long as the combination 
does not exceed the maximum listed 
in table 7 above. 
						

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Installation instructions13
Calculation example for 3 venting: 
Exhaust 
Combustion air
Calculation example for 4 venting: 
Exhaust 
Combustion air
System usedConcentric
Number of 90° elbows needed: 1 
Number of  45° elbows needed: 2
Table 8
Calculation of example 
Max. length 23’ 
90 ° elbow reduction - 5’
sub-total = 18’
45 ° elbow reduction - 6’
Total = 12’
Table 9
i
For this example, the maximum allowable  
exhaust pipe length is  12 feet.
System usedConcentric
Number of 90° elbows needed: 2 
Number of  45° elbows needed: 1
Table 10
Calculation of example 
Max. length 23’ 
90 ° elbow reduction - 10’
sub-total =  13’
45 ° elbow reduction - 3’ Total = 10’
Table 11
i
For this example, the maximum allowable  
combustion air pipe length is  10 feet.
System usedTwin pipe
Number of 90° elbows needed: 1 
Number of  45° elbows needed: 2
Table 12
Calculation of example 
Max. length 63’ 
90 ° elbow reduction - 2.5’
sub-total = 61.5’
45 ° elbow reduction - 3’
Total = 58.5’
Table 13
i
For this example, the maximum allowable  
exhaust pipe length is  58.5 feet.
System usedTwin pipe
Number of 90° elbows needed: 2 
Number of  45° elbows needed: 2
Table 14
Calculation of example 
Max. length 63’ 
90 ° elbow reduction - 5’
sub-total =  58’
45 ° elbow reduction - 3’ Total = 55’
Table 15
i
For this example, the maximum allowable  
combustion air pipe length is  55 feet. 
						

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Installation instructions 
Required direct vent terminal clearances (twin pipe
 / concentric penetration)
Fig. 9
* For clearances not specified in ANSI Z223.1 / NFPA  54 or CSA-B149.1, one of the following shall be indicated:
a) A minimum clearance value determined by testing  in accordance with section 2.20, or;
b) A reference to the following footnote: 
“Clearance in accordance with local installation co des and the requirements of the gas supplier.”
6720608836-23.1Av
Canadian installations1)U.S. installations2)
AClearance above grade, veranda, porch, deck or balc ony 12 in. 12 in.
B Clearance to window or door that may be opened 36 in . 12 in.
C Clearance to permanently closed window **
D Vertical clearance to ventilated soffit located abo ve the vent 
terminator within a horizontal distance of 2 feet ( 61cm) from the 
center line of the terminator *
*
E Clearance to unventilated soffit **
F Clearance to outside corner **
G Clearance to inside corner **
H Clearance to each side of center line extended abov e meter/
regulator assembly 36 in. within a height 15 feet above 
meter/ regulator assembly *
I Clearance to service regulator vent outlet 36 in.*
J Clearance to non-mechanical air supply inlet to bui lding or the 
combustion air inlet to any other application 36 in. 12 in.
K Clearance to mechanical air supply inlet 72 in. 36 in. above if within 10 feet 
horizontally
L Clearance above paved sidewalk or paved driveway lo cated on 
public property 84 in. 
3)*
M Clearance under veranda, porch deck or balcony 12 in . 
4)*
Table 16
1) In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
2) In accordance with the current ANSI Z223.1 / NFPA  54 National Fuel Gas Code
3) A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
4) Permitted only if veranda, porch, deck or balcony  is fully open on a minimum of two sides beneath the floor. 
						

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Installation instructions15
Required other than direct vent terminal clearances
 (single pipe penetration)
Fig. 10
* For clearances not specified in ANSI Z223.1 / NFPA  54 or CSA-B149.1, one of the following shall be indicated:
a) A minimum clearance value determined by testing  in accordance with section 2.20, or;
b) A reference to the following footnote: 
“Clearance in accordance with local installation co des and the requirements of the gas supplier.”
6720608836-23.1Av
Canadian installations1)U.S. installations2)
AClearance above grade, veranda, porch, deck or balc ony 12 in. 12 in.
B Clearance to window or door that may be opened 36 in . 4 feet below or to side of opening; 
1 foot above opening
C Clearance to permanently closed window **
D Vertical clearance to ventilated soffit located abo ve the vent 
terminator within a horizontal distance of 2 feet ( 61cm) from the 
center line of the terminator *
*
E Clearance to unventilated soffit **
F Clearance to outside corner **
G Clearance to inside corner **
H Clearance to each side of center line extended abov e meter/
regulator assembly 36 in. within a height 15 feet above 
meter/ regulator assembly *
I Clearance to service regulator vent outlet 36 in.*
J Clearance to non-mechanical air supply inlet to bui lding or the 
combustion air inlet to any other application 36 in. 4 feet below or to side of opening; 
1 foot above opening
K Clearance to mechanical air supply inlet 72 in. 36 in. above if within 10 feet 
horizontally
L Clearance above paved sidewalk or paved driveway lo cated on 
public property 84 in. 
3)84 in.
M Clearance under veranda, porch deck or balcony 12 in . 
4)*
Table 17
1) In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
2) In accordance with the current ANSI Z223.1 / NFPA  54 National Fuel Gas Code
3) A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.
4) Permitted only if veranda, porch, deck or balcony  is fully open on a minimum of two sides beneath the floor. 
						

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Installation instructions 
3.3.3 Vent configuration examples 
Below are approved examples of vertical and horizon
tal 
venting installations. 
Fig. 11 Vertical venting system (single pipe penetra -
tion)
Fig. 12 Horizontal venting installation (combustion  air
piping not shown)
Warning: Single pipe penetration should be used in  
non-freezing climates only! Fig. 13 Horizontal venting system (concentric vent) 
Fig. 14 Horizontal parallel venting system (twin pip
e 
direct vent)
6720608836-24.2V
3 (80mm)
INTAKE EXHAUST
MAINTAIN 12 IN. (18 IN. FOR CANADA)
MINIMUM CLEARANCE ABOVE
HIGHEST ANTICIPATED SNOW LEVEL. MAXIMUM OF 24 IN. ABOVE ROOF.
DRAIN TEE
4
HORIZONTAL RUN
DOWN TO
TERMINATOR.
SIDE OF
WATER
HEATERNOTE: 
MINIMUM1FT OF 
STRAIGHT VENT PIPE 
REQUIRED
6720608542-10.1V
6720608643-11.2V
3 (80mm)
3 (80mm)
INTAKEEXHAUST
MINIMUM
1”
EXHAUST
COMBUSTION AIR
DRAIN TEE
6720608836-25.1Av 
						

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Installation instructions17
Fig. 15 Horizontal venting system (single pipe pene-
tration)
*Warning: Single pipe penetration should be  
used in non-freezing climates only! 
3.3.4 Vent connections
Attaching the exhaust and air inlet connection  
adaptors to the top of the heater B Attach the flue gas exhaust accessory to the top of  
the unit Fig. 16 (position 1) using the 4 screws an d 
gasket provided, and fully insert vent pipe into th e 
accessory. If using 4 venting, a 3 to 4 increase r 
should be installed directly after this accessory. Fig. 16 Exhaust connectionB
Attach the combustion air inlet accessory to the to p 
of the unit Fig. 17 (position 2) using the 3 screws  and 
gasket provided, and install 3 air intake pipe ove r the 
accessory.
Fig. 17 Inlet connection 
3.3.5 Connecting the condensate water drain
i
NOTE:  Vent  pipe  must  be  completely 
vertical  when  inserting  or  blue  gasket
inside  exhaust  accessory  can  become
displaced.  Exhaust  accessory  can  be
removed with vent pipe attached to check
gasket position.
6720608643-12.2V
3 (80mm)
INTAKE
EXHAUST
4” Min.
DRAIN TEE
i
NOTE: The combustion air accessory can  
be installed on the top right or on the top 
left side of the heater. The combustion air 
inlet that is not used must be kept sealed. 
Warning:  B Failure to properly install condensate  
drain can damage the appliance and will 
void the warranty.
Warning:  BDo not install condensate drain tubing in  
areas where it may freeze.
6720608836-26.1Av
1. 
						

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Installation instructions 
Appliance condensate drain installation 
The  appliance  comes  equipped  with  an  internal 
condensate drain and siphon. This drains condensati
on
formed  in  the  secondary  heat  exchanger.  Piping  must
be  installed  under  the  condensate  drain  outlet  on  t he
water heater and piped for disposal in accordance w ith
local codes. 
Fig. 18 Appliance drain installation External condensate drain installation 
If an external condensate drain (installer supplied
) must
be  installed  (Section  3.3.2),  the  following  is 
recommended: 
• 1. Install condensate drain on a horizontal sectio n of
the exhaust pipe as close to the heater as possible .
• 2. The condensate must be disposed of according to local codes.
• 3.  To  install  condensate  drain  in  vent  system,  use PVC 3 X 3 X 1.5 tee (part# 196278) and reduce 
for drain connection.
Fig. 19 External condensate drain installation 
3.3.6 Freeze prevention 
In cold climates, components of a tankless water he ater 
can freeze and burst from negative draft. A leading  
cause of negative draft is combustion appliances in  the 
building not being supplied with sufficient combust ion 
air. A wood stove or furnace can pull its combustio n air 
from the water heater‘s vent pipe, allowing the col d 
incoming air to freeze the cold water in the heat  
exchanger. Supplying more combustion air for all co m-
bustion appliances is the solution. A HVAC speciali st 
should be consulted to design solutions for providi ng 
more combustion air. 
Listed below is an additional measure designed to f ur-
ther limit backdraft in extreme conditions assuming  all 
other possible causes have been addressed.
i
The  condensate  must  be  disposed  of  in 
accordance with local codes.
See  chapter 3.11  “Filling  the  condensate
trap”.
i
Use materials approved by the authority 
having jurisdiction. In the absence of other 
authority, PVC, and CPVC pipe must
comply with ASTM D1785, F441 or 
D2665. Cement and primer must comply 
with ASTM D2564 or F493. For Canada,
use CSA or ULC certified PVC or CPVC 
pipe, fittings and cement, see table 2.
Leave min. ¼ air gap
1 ½ x ½ PVC Reducer
Trap required
6720608643-17.2V
Dispose of condensate in  
accordance with local codes
4” Min.
Condensate drain 
						

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Installation instructions19
Backdraft reducer 
The Heat Fab backdraft reducer (9301BFP) is the pre
-
ferred option for limiting backdraft (see Fig. 20).
Note: The following solution is available only for  
3 diameter venting. 
Fig. 20 Part nr 9301BFP 
Installation 
For this solution to be effective, the internal fla pper must 
be 100% closed when the water heater is not running . 
Refer to Figures 22 and 23 for preferred installation  
positions in the vent system. 
Installation considerations:
• Install damper per the supplied manufacturer‘s  instructions.
• The damper is only to be used in the exhaust vent  piping.
• Ensure directional arrow on damper label faces in  the 
same direction as exhaust flow.
• If installed horizontally, the axis must be horizo ntal or 
slightly pitched up towards termination to ensure  
damper closes 100% when heater is not running.
• To allow accessibility, damper must not be install ed 
in an enclosed section of vent pipe.
• Do not install damper in unconditioned spaces (e.g . 
attics) Condensation can build up while the heater  is 
running which can later freeze and potentially bloc k 
the flapper.
Fig. 21 Blackflow reducer (9301BFP) installed Fig. 22 
Fig. 23
6720608643-18.1V
6720608643-19.1V
6720608542-06.2V
Preferreddamperpositionforverticalterminations
Unconditioned space.Donot
installdamper.
Enclosedventpipe.Donot
installdamper.
6720608836-30.2V      
						

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Installation instructions 
3.3.7 Fan speed adjustment 
! IMPORTANT INFORMATION: 
Natural  gas  heaters  with  installation  altitudes
below  2,000  ft  above  sea  level  disregard  this
section. 
Installation adjustment: 
After installing the tankless water heater, the fan
 speed
values  for  minimum  power  (P2)  and  maximum  power 
(P1)  may  need  adjustment  due  to  variations  in  altit ude
and  vent  pipe  length.  Failure  to  make  necessary
adjustments to fan speed values may result in impro per
operation of the appliance. 
First  calculate  the  total  equivalent  vent  length.  T his  is
the straight pipe length of both exhaust and combus tion
air  plus  the  number  of  elbows  used.  To  determine  th e
length equivalency of each elbow refer to tables 5 a nd
6. 
Use  the  equivalent  vent  length  value  to  determine  t he
appropriate fan speed values found in table 18 and 19 .
Refer to page 22 on how to adjust the fan speeds if  an
adjustment is necessary.  After changing fan speed  val-
ues, proceed to section 6.5 to confirm CO2 values a re
within specified ranges.