Download  Print this page

Measuring Gas Pressure - Bosch Pro Tankless GWH-450-ES Series Manual

Temperature modulated with electronic ignition - normal duty suitable for recirculating potable water only
Hide thumbs


Installation instructions
National Fuel Gas Code requires that a sediment trap
(drip leg) be installed on gas appliances not so
equipped. Also, a manual gas shut off valve must be
installed on the gas supply line within close proximity of
the water heater and be visible from the water heater.
Warning: The water heater must be
disconnected from the gas supply
piping system during any pressure
testing of that system at test pressures
equal to or more than 0.5 psig.
The water heater must not be piped with gas supply
pressures in excess of 0.5 psig. If overpressure has
occurred, such as through improper testing of the gas
lines or malfunction of the supply system, the gas valve
must be checked for safe operation.
When connections are made, check for gas leaks at all
joints. Apply some soapy water to all gas fittings. Soap
bubbles are a sign of a leak.
Danger: If you have a leak, shut off the
gas. Tighten appropriate fittings to stop
leak. Turn the gas on and check again
with a soapy solution. Never test for gas
leaks using a match or flame.

Measuring gas pressure

Connecting manometer
B Turn power off.
B Shut off gas supply.
B Remove front cover and locate the inlet gas
measuring point (see Fig. 22).
B Loosen screw inside test point fitting (do not remove)
and connect manometer tube on test point.
Fig. 22 Gas pressure measuring (lower tapping)
Static pressure test
B Turn gas supply on.
B Operate all other gas appliances on same gas piping
system at maximum output.
B Record static pressure reading in table 7.
Operating pressure test
B Press On/Off button to turn heater On.
B After 10 seconds, press and hold the reset button
B Rotate the recirculating water temperature selector
(left knob) to the minimum and then to maximum.
B Release the reset button and the display should
show * blinking.
B Place a demand for heat by turning thermostat
control to maximum.
B Record operating pressure reading in table 7.
Note: after verification tight the screw
inside the test point.
Operating gas pressures lower than 5" W.C. for natural
gas or 11" W.C. for LP will result in improper operation
and must be corrected. See Chapter 3.7 for gas line
sizing requirements.
Static Gas Pressure Reading (see Chapter 3.8)
enter here: ___________________
Operating Gas Pressure Reading (see Chapter 3.8)
enter here: ___________________
Table 7
6 720 607 915



  Related Manuals for Bosch Pro Tankless GWH-450-ES Series

This manual is also suitable for:

Pro tankless gwh-450-es-nPro tankless gwh-450-es-l