Raypak XTherm Series Installation & Operating Instructions Manual page 39

High & 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 pan-
els on the side or front of the heater 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 pressure switch
automatically shuts down the heater if gas supply
drops below the factory setting of 3.0 in. WC for natu-
ral gas or propane gas.
The high gas pressure switch is standard, and is
mounted downstream of the gas valve. 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. 47 to reset a tripped pressure switch. The LED
will go out when the switch is reset.
Fig. 47: High/Low Gas Pressure Switch
Blocked Vent Switch
This heater is equipped with a blocked vent pressure
switch to prevent the operation of the heater when too
much of the vent is blocked. This switch is located on
the right side of the heater near the right rear corner.
Fig. 48: Blocked Vent Switch
Proportional Two-Way Valve
Fig. 49: Proportional Two-Way Valve
NOTE: Always have the actuator set on 'normal'.
Do not use the 'master' or 'slave' settings. On the B
side, have the actuator set on 'RA 0-10'.
The XTherm is equiped with a proportional two-way
valve to provide flow control for CWP (for more infor-
mation see VERSA IC cat. 5000.72). Factory default
settings shown in Fig. 50.
For applications using CWP, ensure the most appro-
priated setting selection for MIX TYPE setting. This
setting is located at the setup menu in the VERSA
display. For detailed information see VERSA IC Cat.
5000.72.
Placing 2-way Valve into Service Position
1. Identify the tie strap that fastens the actuator to
the mounting bracket.
2. Cut the nylon tie strap and discard the strap.
3. Loosen the 7/16" nut, lock washer and bolt on the
bottom of the anti-rotation bracket.
4. Slide the bracket away from the shaft to clear the
39
H model
MASTER
SLAVE NORMAL
CAL
2 - 10 2 - 10
RA DA
0 - 10 0 - 10
Side B of Actuator
WH model