Raypak MVB 504A, Installation & Operating Manual

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Fig. 38: High Limit (Manual Reset)
If either the Outlet or Inlet temperature drops below
38°F, the VERSA starts the burner at the minimum fir-
ing rate. The burner cycle will terminate when both the
Inlet and Outlet temperatures rise above 42°F.
Controls
36
Fig. 37: Outdoor Venting
WARNING: Installation, adjustment and service of
heater controls, including timing of various operating
functions, must be performed by a qualified installer,
service agency or the gas supplier. Failure to do so
may result in control damage, heater malfunction,
property damage, personal injury, or death.
WARNING: Turn off the power to the heater before
installation, adjustment or service of any heater
controls. Failure to do so may result in board
damage, heater malfunction, property damage,
personal injury, or death.
CAUTION: This appliance has provisions to be
connected to more than one supply source. To
reduce the risk of electric shock, disconnect all such
connections before servicing.
CAUTION: Risk of electric shock: More than one
disconnect switch may be required to de-energize
the equipment before servicing.
Ignition Control Functions
When there is a call for heat, and all safeties are
closed, then the combustion air blower starts to purge
air from the combustion chamber. After the pre-purge,
the igniter is energized. The standard ignition module
will lock-out after failing to light 3 times during a call for
heat. To reset the lock-out, press and release the
RESET button located on the user interface. The con-
trol will automatically reset after 1 hour. When in
lock-out the control will run the blower through a post-
purge cycle.
The single-try ignition module (part of the CSD-1
option) will attempt to light only one time before lock-
out occurs. To reset the lock-out, press and relase the
RESET button located on the user interface.
Turning off the power to the heater WILL NOT reset
the single-try ignition module.
NOTE: Ignition modules are common for all model
sizes. However, model-specific operating parame-
ters are defined by their respective ID cards.
High Limit—Manual Reset
This heater is equipped with a fixed setting manual re-
set high limit temperature device as standard. It may
also have an additional optional adjustable manual
reset high temperature device.
The optional adjustable manual reset high limit is
located inside the cabinet on the upper left corner
post. Access the limit by hinging the control box open
to view and make adjustments.