Bosch Greentherm T9800 SEC 199 Installation And Operating Instructions Manual page 20

20 | Installation instructions
4.6.3 Vent specifications
Establish vent clearances that comply with the vent
manufacturer's specifications and all applicable national/local
codes.
Minimum combustion air and exhaust pipe length
The minimum exhaust pipe length is 1 ft (0.3m) of straight vent
pipe. The minimum air intake pipe length is 1 ft or one 90°
elbow or an air intake grill cap to prevent debris from falling into
the appliance.
Maximum combustion air and exhaust pipe length
The table 8 displays the maximum allowable straight pipe
lengths for air intake and exhaust piping. Reduce the maximum
allowable pipe length by the equivalent lengths for each elbow
used and termination used.
PROPER GAS PRESSURE!
The following section assumes the water
heater will receive gas pressure greater than
or equal to 5" WC for the 199kBTU models
(4" WC for 160kBTU models). In cases of gas
pressure below 5" WC for the 199kBTU (4"
WC for the 160kBTU models) the maximum
heat input is reduced.
The values of maximum flue length in
table 8 are before any deductions for
elbows or terminations.
Venting Max equivalent
Exhaust length
2" Twin pipe
3" Twin pipe 280ft
2"/ 4"
Concentric pipe
3"/ 5"
Concentric pipe
Table 8 Maximum Allowable Exhaust and Air Intake Lengths
1) To assure maximum heat input at maximum vent length
minimum gas pressure should be 5" W.C. for the 199 kBTU
models and 4" W.C. for the 160 kBTU models.
Improper gas pressure or vent length may
result in undesired symptoms or errors such
as noisy burner, C1, C2, CF.
6 720 816 815 (2018/08)
Max equivalent
Intake length
1)
60ft 60ft
1)
280ft
1)
60ft
1)
280ft
The vent for this appliance shall not terminate:
1. over public walkways; or
2. near soffit vents or crawl space vents or other areas where
condensate or vapor could create a nuisance or hazard or
cause papery damage; or
3. where condensate vapor could cause damage or could be
detrimental to the operation of regulators, relief valves, or
other equipment.
Greentherm T9800 SE 160/199 | SEC 199