Onan 25.0 DEH-53R Series Operator's Manual And Parts Catalog page 31

COOLANT CORROSION RESISTOR
(Water Filter)
The PAF formula elements can be used with most
permanent antifreezes, but is not recommended for
use with plain water. It is necessary to drain and flush
the system thoroughly when changing from one
element formula to the other if a non-compatible
antifreeze is in use. See Figure 10 for view of the
system.
At each 300 to-500 hour interval of operation,
depending on conditions, service the coolant filter as
follows:
1. Thoroughly clean filter body and surrounding
area.
2. Close coolant inlet and outlet shutoff valves.
3. Remove drain plug from bottom of filter body and
drain coolant.
4. Remove capscrews attaching filter cover to body
and remove cover (Figure 26).
5. Lift upper plate and filter element out of filter
body. Discard filter element.
6. Remove lower corrosion resistor plate and spring
from filter body.
7. Inspect and clean lower corrosion resistor plate,
buffing it to a bright finish. If plate is thin and
pliable, or has developed holes, replace it.
8. Remove and clean sump plate. Clean sump area
in filter body.
9. Install sump plate, spring, and lower corrosion
resistor plate.
10. Install new filter element. '
11. Position upper plate in filter body.
12. Make certain gasket is ih good condition, then
install cover and secure with attaching
capscrews.
13. Replace drain plug and open inlet and outlet
shutoff valves.
UPPER P L A T E
F I L T E R E L E M E N T
CORROSION
RESISTOR P L A T E
SPRING
F I L T E R BODY
MODEL OS
FIGURE 26. CHANGING CORROSION RESISTOR
ELEMENT ANO PLATE
Initially the element should be changed after 150 hours of operation
for borate (PAF) formula filter elements.
Do not use soluble oil or other conditioners in the
cooling system. However, filter efficiency is not
affected by use of permanent type antifreeze in the
system.
P c A U T I O N ^
If a stop-leak is added to the coolant, do not
allow it to circulate through the filter. Shutoff
valves are provided in inlet and outlet lines for isolating the filter
from remainder of cooling system.
Whenever coolant supply is changed (spring and fall), the system
must be drained and flushed.
On an extremely dirty system, the coolant should be
drained and flushed before a new element is installed.
In a few rare cases, additional flushing and change of
filter may be necessary in order to completely purge
the system. Generator sets subject to excessive idling
or frequent start and stop cycles, or units located in
areas with dust, air contaminants, or other noxious
atmospheric conditions, will require more frequent
servicing.
After maintenance has been completed, check flow
indicator if one has been installed to see if air bubbles
(which can cause pump cavitation) are in the system.
If air is present, bleed the system by disconnecting
the filter outlet line momentarily until the coolant
flows in a solid stream.
GENERAL ENGINE MAINTENANCE
Refer to the engine manual furnished with the
generating set for additional details on servicing
procedures not covered by this manual. Refer to
Table 5 for general information on clearing the
electric generating set of any malfunctions which
have developed during the period of operation.
29