54
supply gas pressure adjustment
Fire and Explosion Hazard
Turn off gas lines during installation.
Contact a qualified installer or service
agency for installation and service.
Excessive gas pressure to gas valve can
cause serious injury or death.
Do not use water heater with any gas
other than the gas shown on the rating
label.
Supply gas pressure shall be measured while the water heater is
not firing (static pressure)
aND
while the water heater is firing at
full capacity (dynamic pressure).
If the supply gas pressure to the water heater is not between the
required minimum and maximum values given in Table 3 on page
12 adjust the supply gas regulator as necessary. Adjust the supply
gas regulator(s) per the regulator manufacturer’s instructions to
achieve the required “static” and “dynamic” supply gas pressure.
multiple water heater installations:
In multiple water heater installations or in installations where
the installed water heater(s) share a common gas supply main
with other gas fired appliances; the supply gas pressures shall
be measured at each water heater with all gas fired appliances
connected to a common main firing at full capacity.
On multiple water heater installations the supply gas line
regulators shall be adjusted to provide gas pressure to each
water heater within the minimum and maximum supply pressure
requirements listed in Table 3 on page 12 with all gas fired
appliances connected to a common gas main firing at full capacity.
note:
A pressure drop of more than 1.5” W. C. (0.37 kPa) when
the main Burner ignites is an indication of an inadequate supply
of gas and can lead to ignition failure, rough starts and/or rough
operation. If a drop of more than 1.5” W. C. (0.37 kPa) in supply
gas pressure occurs when the main Burner ignites, ensure the
supply gas lines and regulator(s) are properly sized and installed.
See the requirements for Supply Gas regulator and Gas Supply
Systems on page 14. See Supply Gas Line Installation on
page 39 and Supply Gas regulator on page 14. Ensure all
requirements and installation instructions are maintained.
manifold gas pressure adjustment
Fire and Explosion Hazard
Gas and carbon monoxide detectors are
available.
Overfiring could result in fire or
explosion.
Under no circumstances should the
input exceed the rate shown on the
water heater’s rating label.
Breathing Hazard - Carbon Monoxide Gas
Breathing carbon monoxide can cause brain damage or
death. Always read and understand instruction manual.
Under no circumstances should
the input exceed the rate shown
on the water heater’s rating label.
Overfiring could result in damage to
the water heater and sooting.
Gas and carbon monoxide detectors
are available.
Ensure the "dynamic" supply gas pressure is above the
minimum requirements in Table 3 on page 12 before any
adjustments are made to the manifold gas pressure. Attempts
to adjust manifold gas pressure during periods of low supply gas
pressure could result in overfiring when the supply gas pressure
returns to normal. See Supply Gas Pressure Adjustment on this
page.
note:
manifold gas pressure is non-adjustable on BTH 199 and
BTH 250 models. The manifold gas pressure on these models
is factory set and cannot be field adjusted. If the manifold gas
pressure readings taken on these models is off by more than ±
0.3" W. C. from the listed values in Table 3 on page 12 call the
technical support phone number listed on the back cover of this
manual for further assistance.
Follow the steps below to adjust the manifold gas pressure
on BTH 120 and 150 models:
1. Follow the instructions for Initial Start Up on page 52
to connect manometers to the supply and manifold gas
pressure taps and to start the water heater.
2. remove the manifold gas pressure regulator cover
screw, see Figure 57 on page 53.
3. Using a small flat tip screw driver turn the adjustment
screw clockwise to increase manifold gas pressure and
counter clockwise to decrease manifold gas pressure.
note:
Turn the manifold gas pressure adjustment
screw in small increments (no more than 1/4 turn) and
allow the manifold gas pressure to stabilize for several
minutes before making further adjustments.
4. replace the gas pressure regulator cover screw.
5. Cycle the burner on and off several times to check
operation.
