Raypak Xfiire 300B Installation And Operation Manual page 47

The fixed-setting manual reset high limit is built into the
PIM, and utilizes a dual thermister sensor located on the
outlet.
H 200ºF (93ºC)
WH 180ºF (82ºC)
To reset a high limit lock-out, press and release the RESET
button located adjacent the user interface or the RESET
button located on the face of the optional MRHL.
High Limit - Auto Reset (Optional)
This heater may be equipped with an optional adjustable
auto-reset high limit temperature device.
The optional adjustable auto reset high limit is located
inside the cabinet on the upper right corner post. See
Figure 2. Adjust the setting to approx. 20°F (11°C) above
desired outlet temperature.
Figure 49. Adjustable High Limit (Auto Reset)
Flow Switch
This standard, dual-purpose control, mounted and wired in
series with the main gas valve, shuts off the heater in case
of pump failure or low water flow. See Figure 1.
Low flow causing the flow switch to open during operation
will create a soft lockout that will automatically reset after
15 minutes. This functionality will prevent short-cycling of
the burner due to marginal water flow.
Figure 50. Flow Switch
F10494
Low Water Cut-Off
The low water cut-off automatically shuts down the burner
whenever water level drops below the level of the sensing
probe. See Figure 1. A 5-second time delay prevents
premature lockout due to temporary conditions such as
power fluctuations or air pockets. The low water cut-off
control is located in the control box.
Figure 51. Low Water Cut-Off
High and Low Gas Pressure
Switches (Optional)
The optional low gas pressure switch mounts upstream of
the gas valve (on the inlet flange to the gas valve) and is
accessible through the removable access panels on the
top or front of the heater to reset the gas pressure switch,
as necessary. See Figure 1. It is used to ensure that
sufficient gas pressure is present for proper valve/regulator
performance. The low gas pressure switch automatically
shuts down the heater if gas supply drops below the factory
setting of 3" WC for natural gas or propane gas.
The high gas pressure switch is standard, and is mounted
downstream of the gas valve. See Figure 1. If the gas
pressure regulator in the valve fails, the high gas pressure
switch automatically shuts down the burner.
The low gas pressure switch must be set at 3" WC for either
Nat or Propane Gas. The high gas pressure switch must
be set at 3" WC for either Nat or Propane Gas. Scales
on switches are approximate. Use manometer to set the
switch settings.
Operation of either the High or Low Gas Pressure Switch
will turn on an LED inside the switch housing. Push the
top of the plastic switch housing as shown in Figure 52 to
reset a tripped pressure switch. The LED will go out when
the switch is reset. No bleed line is required.
Figure 52. High/Low Gas Pressure Switch
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