EHC SYSTEM CHEMICAL FLUSHING
PROCEDURE
OUTLINE-Fossil Unit
1. Prepare System for Flush
a. Hydraulic Power Unit
i. Remove Side Steam Filter Elements (not used during flush)
ii. Remove Pump Discharge Filters
iii. Clean Pump Suction Strainer/s
iv. Remove and Recondition Accumulators (reconditioning can be
done concurrent with Flush)
b. EHC Fluids
i. Transfer Rinse Fluid from Barrels to Totes
ii. Transfer Final Operating Fluid from Barrels to Totes
iii. Continuously Filter Fluid in Totes until needed.
c. Protective System
i. Jumper around Trip System Valves
ii. Remove and recondition Protective System Accumulators (If
provided)
d. Steam Valve Actuators
i. Remove and recondition hydraulic actuators and jumper hydraulic
lines to be flushed or install flushing valves on hydraulic actuators
in order to flush lines and actuators.
Note it is highly recommended that the hydraulic actuators be
removed and reconditioned during the flush and only the pipes
be flushed. This insured the actuators are thoroughly cleaned
following the flush since it is impossible to get high velocity
flows through the actuators during the flush.
2. Chemical Flush
a. Start One Hydraulic Power Unit Pump and Check Systems for Leaks
b. Start Second Hydraulic Power Unit Pump and Check System for
Leaks
c. Functionally check system (flushing valves and/or jumpers)
d. Bring fluid to 130F (Both pumps running for flushing)
e. Add Flushing Chemistry to existing fluid in Reservoir (Oleylamine-
1% of reservoir capacity)
f. Flush each line while maintaining fluid temperature between
i. 1st cycle = 30 minutes per line
ii. Remaining cycles = 10 minutes per line
iii. Take periodic fluid samples and analyze the fluid (Generally it takes
4 cycles to get all of the gels and varnish dissolved and or dislodged.
It may take more cycles).
iv. When no hard varnish is observed under the microscope and the
particulate counts are no longer increasing (generally we see a
decrease in particulate counts) the Chemical Flush is complete.
3. Preparations for Rinse Flush
a. Shut down lockout and tagout Hydraulic Power Unit Pumps
b. Depressurize the system and open and all flushing valves and or
jumpers
c. Drain and thoroughly clean the Hydraulic Power Unit Reservoir using
non-chlorinated solvent and lint free rags
d. Drain and clean the Side Stream Filter Housing
e. Remove and Clean Pump Suction Strainer/s
f. Install new Pump Discharge Filter elements
g. Install new Air Breather material
h. Drain Hydraulic Power Unit Coolers
i. Drain all low point drains within hydraulic fluid system
j. Fill Reservoir with new filtered Rinse Fluid
4. Rinse Flush
a. Start both Hydraulic Power Unit Pumps and Check Systems for Leaks
b. Bring fluid to 120F.
c. Flush each line for 10 minutes per cycle while maintaining fluid
temperature between 120F-130F.
i. Take periodic fluid samples and analyze (Generally it takes 2 cycles
to get the system clean or residue left behind during Chemical
Flush. It may take more cycles).
ii. When consistently low particulates are observed under the
microscope
the Rinse Flush is complete.
5. Restoring the Hydraulic Fluid System
a. Hydraulic Power Unit
i. Shut down lockout and tagout Hydraulic Power Unit Pumps
ii. Depressurize the system and open all flushing valves and/or
jumpers
iii. Drain and thoroughly clean the Hydraulic Power Unit Reservoir
using non-chlorinated solvent and lint free rags
iv. Drain and clean the Side Stream Filter Housing and install new
filter elements
v. Remove and clean or replace Pump Suction Strainer/s
vi. Replace Pump Discharge Filters with new filter elements
vii. Drain Hydraulic Power Unit Coolers
viii. Drain all low point drains
ix. Install reconditioned HPU Accumulators
x. Fill Reservoir with new filtered Final Operating Fluid
b. Protective System
i. Remove jumpers assembly and reconnect all lines.
ii. Install reconditioned or new accumulator is provided
c. Steam Valve with actuators in place
i. Replace flushing valves with new or reconditioned servo valves and
solenoid valves
ii. Remove, clean, inspect and reassemble all Dump Valves if
equipped
d. Steam Valves with Actuators removed for refurbishing during flush
i. Replace jumpers with reconditioned hydraulic actuators. The
actuators should have either reconditioned or new servo valves,
solenoid valves and dump valves.
6. Restart of System
a. Start One Hydraulic Power Unit Pump and check system for leaks
b. Start Second Hydraulic Power Unit Pump and check system for leaks
c. Reset turbine controls and check system for leaks
d. Stroke all steam valves and check system for leaks
EHC SYSTEM INTACT RINSE PROCEDURE
OUTLINE-Fossil Unit
1. Prepare System for Rinse
a. Hydraulic Power Unit
i. Drain Side Steam Filter housings and remove filter elements (not
used during Rinse)
ii. Replace Pump Discharge Filters with new elements
iii. Clean Pump Suction Strainer/s
iv . Drain and thoroughly clean Hydraulic Power Unit Reservoir using non-chlorinated solvent and lint free rags.
v. Drain Hydraulic Power Unit Coolers
vi. Drain all low point drains within hydraulic fluid system
vii. Fill Reservoir with new Rinse Fluid
2. Rinse
a. Start One Hydraulic Power Unit Pump and Check Systems for Leaks
b. Bring fluid to 110F.
c. Reset Turbine Control System
d. Stroke all hydraulic actuator 3-4 times fully opened and closed
e. Trip Turbine Control System
f. Shut off first Hydraulic Power Unit Pump and start Second Hydraulic
Fluid Pump and check for leaks.
g. Shut down pumps
h. Depressurize the hydraulic fluid system.
3. Restoring the Hydraulic Fluid System
a. Hydraulic Power Unit
i. Drain and thoroughly clean the Hydraulic Power Unit Reservoir
using non-chlorinated solvent and lint free rags
ii. Drain and clean the Side Stream Filter Housing and install new
filter
elements
iii. Remove and clean or replace Pump Suction Strainer/s
iv. Replace Pump Discharge Filters with new filter elements
v. Drain Hydraulic Power Unit Coolers
vi. Drain all low point drains
vii. Fill Reservoir with new Final Operating Fluid
4. Restart of System
a. Start One Hydraulic Power Unit Pump and check system for leaks. Shut
down pump
b. Start Second Hydraulic Power Unit Pump and check system for leaks
c. Reset turbine controls and check system for leaks
d. Stroke all steam valves and check system for leaks
