Flow Switch
This standard, dual-purpose control shuts off the boil-
er in case of pump failure or low water flow. The flow
switch ships mounted and wired.
Fig. 33: Low Water Cut-Off
Flue Temperature Limit
The heater is equipped with a fixed setting manual
reset high limit temperature device on the vent, for use
with non-metallic vent material. The high temperature
limit is located inside the unit near the vent adapter.
The VERSA monitors the limit and displays any fault
associated with the limit on the user interface. To reset
the limit, access it and press down on the red button.
The unit is provided with a limit rated for PVC vent
material. A higher rated limit is provided when using
Centrotherm™ polypropylene venting. The limit is
removed when using Category IV stainless steel vent-
ing.
Low Water Cut-Off (Optional)
The optional low water cut-off automatically shuts
down the burner whenever water level drops below the
level of the sensing probe. A 5-second time delay pre-
vents premature lockout due to temporary conditions
such as power fluctuations or air pockets.
Fig. 31: Flow Switch
Fig. 32: Flue Temperature Limit
High & Low Gas Pressure Switches
(Optional)
The optional low gas pressure switch connection
mounts upstream of the gas valve (on the inlet flange
to the gas valve) and is accessible through the remov-
able access panels on the front or top of the boiler to
reset the gas pressure switch, as necessary. It is used
to ensure that sufficient gas pressure is present for
proper valve/regulator performance. The low gas pres-
sure switch automatically shuts down the boiler if the
gas supply drops below the factory setting of 3.0 in.
WC for natural gas or propane gas.
The optional high gas pressure switch connection
mounts down-stream of the gas valve. Special ports
are located on the backside of the gas valve and are
accessible from the front or top of the boiler (to reset
the gas pressure switch), as necessary. If the gas
pressure regulator in the valve fails, the high gas pres-
sure switch automatically shuts down the burner.
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
Fig. 34 to reset a tripped pressure switch. The LED will
go out when the switch is reset.
36
Summary of Contents for XFyre 300A
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