Marsh Hawk TRV Installation, Operation and Maintenance Guide - May 20224
and the gasket is adequately compressed to prevent
leakage. Replace if damaged.
8" API
TANK GASKET
4. Inspect the Spider Cage. Ensure that all of the parts are
present and assembled as shown above. All bolts and
screws should be snug.
5. Inspect the springs. They should be under tension/
compression at all times and should therefore hold
the vacuum pallet against the vacuum seal and the
spring retainer against the top washer. If the vacuum
pallet does not stay closed on its own or the pressure
spring is loose when assembled, the springs have lost
their temper and should both be replaced. In severe
conditions Inconel springs may be required.
ENSURE SPRINGS MAINTAIN
TENSION/COMPRESSION
6. Inspect the Marsh Hawk body and inner sealing
surface. Look for signs of pitting, corrosion and wear.
Replace if damaged.
INSPECT BODY AND INNER
SEALING SURFACE
7. If everything clears inspection, apply the
recommended grease in an even coating on both the
pressure and vacuum seals as shown above.
APPLY RECOMMENDED
GREASE
8. Replace the Spider Cage and inject antifreeze agent
(Spider Cage removal in reverse)
C3 TROUBLESHOOTING
PROBLEM: Vent is Leaking of Frequently Opening
Symptom Of Solution
Unlubricated
Pressure / Vacuum
Seal
Perform the inspection and re-
lubrication procedures detailed
in C2. Ensure antifreeze agents
(if used) are compatible with
gasket material (see C4)
Worn or Damaged
Pressure Vacuum
Seal
Set pressure set too
close to operating
pressure
Ensure that the set pressure of
the Marsh Hawk is sufficiently
above the operating pressure
of the tank. Set pressure should
be 2 - 4 ozsi over operating
pressure.
PROBLEM: Vent is not opening
Symptom Of Solution
Debris blocking
action
Open lid and ensure the
vent cavity is clear of debris
and obstructions. If debris
accumulates, consider adding
a TRV Mesh Screen.
Stuck Pressure or
Vacuum Pallet
Remove the Spider Cage
assembly per B1 to ensure the
pressure and vacuum pallets
are free to move and are free
from ice. Ensure antifreeze
agents (if used) are compatible
with gasket material (see C4)
Set pressure set too
far from operating
pressure
Ensure that the set pressure of
the Marsh Hawk is sufficiently
below the desired relieving
pressure and the design
pressure of the tank.
C4 ANTIFREEZE SOLUTIONS
It is not recommended to use any kind of antifreeze
solution on a normally operating Marsh Hawk TRV, even
as a preventative measure unless there is evidence of the
valve icing up.
If antifreeze solutions are used, they must be compatible
with the gasket materials. Consult the chart below to
gauge general compatibility of common antifreeze agents
and Marsh Hawk TRV gasket materials. This list is not
exhaustive.
CAUTION: USING A NONRECOMMENDED ANTI
FREEZE AGENT CAN CAUSE THE MARSH HAWK TRV TO
FAIL TO OPERATE CORRECTLY, BY EITHER VENTING
CONTINUOUSLY OR SEALING CLOSED.
GASKET MATERIAL
ANTIFREEZE
SOLUTION
FKM &
eFKM
FEPM FFKM
Methanol 4 1 1
Ethanol 3 1 1
Isopropanol 1 1 1
Ethylene Glycol 1 1 1
1 - Satisfactory 2 - Fair 3 - Doubtful 4 - Avoid
Contents © Hawkeye Industries Inc. This document is uncontrolled, and is
subject to change without notice. Please refer to www.hawk-eye.com for the
most up-to-date product information.
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Edmonton, AB, Canada T6P 1N6
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