Manifold Gas Pressure - Bosch Greentherm 9800 SE 160/199 Manual

50 | Troubleshooting
2. Improper venting. Ensure venting is in accordance with
specifications in chapter4.6, page 15.
3. Lack of adequate combustion air. Drawing combustion air
from a room area of inadequate size will result in unstable
burner flames and noise. Ensure adequate combustion air
is provided to the unit in accordance with specifications in
Section 4.6.6, page 26.
4. Cross contamination. Ensure that intake and exhaust
terminations maintain required clearances as stated in
chapter 4.6, page 15. Cross contamination between intake
and exhaust may cause unstable burner flames and noise.
5. Lack of gas pressure. Inadequate gas pressure will cause
the fuel-to-air mixture (CO
will result in unstable burner flames and noise. Ensure gas
pressure is in accordance with specifications in
Section4.13, page 36. A gas pressure reading is needed to
proceed further. Contact your original installer or a local
certified gas technician to obtain this reading.
6. Verify proper CO readings per chapter 8.9, page 51. CO
2
adjustments must be done by a certified gas technician
with a calibrated combustion gas analyzer.
8.8

Manifold gas pressure

▶ Turn Off the appliance.
▶ Remove the front cover of the appliance (see page 10).
Fig. 47 Pressure head points
[A] Air pressure head in the box
[B] Gas pressure head in the burner
[C] Tee (installer supplied)
6 720 816 815 (2016/10)
) to be out of adjustment. This
2
▶ Loosen the set screw of the pressure head point [B].
▶ Connect the pressure gauge connection "+" to the test
point [B].
▶ Loosen the set screw of the pressure head point [A].
▶ Connect the pressure gauge "-" to the pressure head point
[A].
▶ Turn On the appliance.
▶ Position the front cover near the appliance and make sure
the cable for the display is connected.
▶ Open all hot water taps to achieve a flow rate of at least 6
gallons per minute. (1 tub and 2 sinks should be sufficient).
If heater goes back to P2, open more hot water fixtures to
allow sufficient flow and access to P1 menu.
▶ Record the manifold gas pressure reading in table 22.
Manifold gas pressure refers to the relative pressure
between gas manifold nozzles inlet and outlet [A]-[B].
2 Manifold gas
pressure
Table 22
▶ Turn Off the appliance.
▶ Disconnect the pressure gauges from the pressure heads
points [A] and [B].
▶ Tighten the shutter screws of the pressure heads points [A]
and [B].
▶ Reassemble the front cover onto he appliance.
▶ Turn ON the appliance to return to normal operation.
Value Date
Greentherm 9800 SE 160/199 | SEC 199