40
Test/Reset
Low Water Cut-Off (Model 398A
Only)
The standard 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. Manual
reset is required to restore operation
All-In-One Low Water Cut-Off
(Models 88AR-278AR)
The standard low water cut-off automatically shuts
down the burner whenever water level drops below the
level of the sensing probe.
This device will automatically reset once the correct
water level is restored. The VERSA control will contin-
ue to maintain lockout for 15 minutes (soft lockout).
During that time, press ‘RESET’ to restart the unit.
High & Low Gas Pressure Switches
(Field Add-On)
The low gas pressure switch connection mounts
upstream of the gas valve (on the inlet flange to the
gas valve) and is accessible through the removable
access panels on the front 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/reg-
ulator performance. The low gas pressure switch
automatically shuts down the boiler if the gas supply
Fig. 40: Low Water Cut-Off
Fig. 41: Low Water Cut-Off
pressure drops below the factory setting of 3.0 in. WC
for natural gas or propane gas.
The high gas pressure switch connection mounts
downstream of the gas valve. Special ports are locat-
ed on the backside of the gas valve and are accessible
from the front or top of the boiler (to reset the gas pres-
sure switch), as necessary. If the gas pressure
regulator in the valve fails, the high gas pressure
switch automatically shuts down the burner.
The High gas pressure switch shuts down the boiler if
the gas supply pressure rises above the factory setting
of 3.0” WC for either natural or propane gas.
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. 42 to reset a tripped pressure switch. The LED will
go out when the switch is reset.
These safety devices can emit small amounts of fuel
gas, and must be piped to a safe discharge location
outdoors, per local code requirements.
Blocked Vent Switch
The heater is equipped with a blocked vent pressure
switch to prevent the operation of the boiler when a
significant amount of air flow is blocked at the vent.
The switch is located at the left rear of the unit.
Fig. 43: Blocked Vent Switch
PRESS
PRESS
TO START
PRESS
T
PRESS
TO ST
PRESS
TO STAR
PRESS
TO START
Fig. 42: High/Low Gas Pressure Switch
Summary of Contents for 88AR-398A
Page 18: ...18 Fig 13 MODE 1 Single Boiler Primary Secondary Piping...
Page 19: ...19 Fig 14 MODE 2 Single Boiler Primary Secondary Piping with Indirect DHW on System Loop...
Page 20: ...20 Fig 15 MODE 3 Single Boiler Primary Secondary Piping with Indirect DHW on Boiler Loop...
Page 47: ...47 WIRING DIAGRAM Fig 46 Wiring Diagram...
Page 54: ...54 Fig 55 Boiler Lighting Shut Off Instructions...
Page 65: ...65 ILLUSTRATED PARTS LIST...
Page 66: ...66...
Page 67: ...67...
