Flowserve recommends replacement of 
all soft parts whenever the valve is disassembled for reconditioning. Replacement 
parts can be ordered in kit form.
4. Reassembly
A.  Put one seat (10) in body (14).
NOTE: Seats (10) are to be installed 
with concave surfaces positioned 
against the ball.
CAUTION: The high-pressure valve 
Model E790K is a uni-directional (oneway) valve and it is extremely 
important that the unslotted 
downstream seat and the slotted 
upstream seat be positioned properly.
The unslotted downstream seat is placed 
in the solid end of the body and the slotted upstream seat is placed in the spacer 
end of the body.
B.  Lightly grease the stem seals (17) and
the seal area and threads of the stem (2). 
Insert stem seal(s) (17) into the lower 
stem seal cavity with the raised outer 
edge facing into the counterbore. (The 
1
/
4"
thru 
1
/
2" size and all sizes of the FIRE-
GARD seals are square cut seals.) Insert 
stem (2) through the installed stem seals 
(17) and the body (14). Place the travel 
stop (5) on the stem (2) so that it rests 
on the top surface of the body (14). 
Thread the adjusting nut (18) on the 
stem (2) and torque to 
3
/
4 of the final
torque value for the adjusting nut (18). 
Remove the adjusting nut (18) and the 
travel stop (5) without moving the stem 
(2). Place the grounding washer (19) into 
the upper seal cavity with the raised fingers pointing up. Push the upper stem 
seal(s) (17) into the counterbore with 
raised outer edge pointing into the valve. 
Add the gland ring (6), the travel stop (5) 
and the adjusting nut (18). Make sure the 
travel stop (5) is installed so that the 
valve can close in a clockwise direction 
and open counterclockwise. If the rotation is not correct, the travel stop (5) 
must be inverted. Torque the adjusting 
nut (18) to the value shown in Figure 3. 
Cycle several times and check the stem 
nut torque.
C.  Turn the stem (2) to a position with the
stem tang flats inside the body parallel 
to the cavity. (Ball will be in the closed 
position and stay in this position through 
steps D, E, F and G.)
D.  Install the ball (9). NOTE: Ball should be
carefully examined for nicks, scratches, 
pitting or corrosion and replaced as 
necessary.
E.  Put other seat (10) into seat socket (8)
and fit up against shoulder in body (14). 
(See note in paragraph 4A.)
F.   Install spacer seal (16).
G.  Install threaded spacer (7) using appro-
priate allen type wrench or hexagonal 
bar. (See Figure 1 on page 1).
NOTE: In order to achieve proper seat 
preload against ball, threaded spacer (7) 
must come to a complete stop when 
screwed into body (14).
H.  Press body seal (11) and end seal (15)
and threaded spacer (7) into grooves on 
face of body and threaded spacer.
I.  Place body (14) back into line position
and tighten union nuts (12).
J.  Install travel stop (5), if required (see
Figure 2), handle (1) and handle retainer 
nut (4).
5. Testing
Prior to placing valve back into line position 
test as follows:
A. Place the closed valve in a vise with the
pipe run in the vertical position and connect air pressure to lower port. 
Introduce 50 to 100 psig air. Pour water 
into upper port to cover the ball and 
visually check for bubbles. If bubbles 
appear, pour the water out, cycle the 
valve several times and recheck. To 
check for leakage in the other port, 
reverse the valve and introduce air pressure to the port just checked.
B. In the event of stem seal leakage, adjust
as described in Section 2 “Stem Seal 
Adjustment.”
Flow Control Division
McCANNA/MARPAC Valves
Flowserve Corporation has established industry leadership in the design and manufacture of its products. When properly selected, this Flowserve product is designed to perform its intended function 
safely during its useful life. However, the purchaser or user of Flowserve products should be aware that Flowserve products might be used in numerous applications under a wide variety of industrial 
service conditions. Although Flowserve can (and often does) provide general guidelines, it cannot provide specific data and warnings for all possible applications. The purchaser/user must therefore 
assume the ultimate responsibility for the proper sizing and selection, installation, operation, and maintenance of Flowserve products. The purchaser/user should read and understand the Installation 
Operation Maintenance (IOM) instructions included with the product, and train its employees and contractors in the safe use of Flowserve products in connection with the specific application.
While the information and specifications contained in this literature are believed to be accurate, they are supplied for informative purposes only and should not be considered certified or as a guarantee of 
satisfactory results by reliance thereon. Nothing contained herein is to be construed as a warranty or guarantee, express or implied, regarding any matter with respect to this product. Because Flowserve 
is continually improving and upgrading its product design, the specifications, dimensions and information contained herein are subject to change without notice. Should any question arise concerning 
these provisions, the purchaser/user should contact Flowserve Corporation at any one of its worldwide operations or offices.
For more information about Flowserve Corporation, contact www.flowserve.com or call USA 1-800-225-6989.
FLOWSERVE CORPORATION 
FLOW CONTROL DIVISION
1978 Foreman Drive 
Cookeville, Tennessee 38501 USA 
Phone: 931 432 4021 
Facsimile: 931 432 3105 
www.flowserve.com
© 2003 Flowserve Corporation, Irving, Texas, USA. Flowserve and Worcester Controls are registered trademarks of Flowserve Corporation. MMAIM2002 (Part IM005)
Stem Nut 
Torques (lb-ft) Number of Seals
SIZE TORQUE UPPER LOWER
1
/
2"5 11
3
/
4" to 2" 10 1 2
NOTICE: McCANNA Valves are designed and manufactured using good workmanship and materials, and they meet all applicable industry standards. Flowserve Corporation is anxious to avoid 
injuries and property damage which could result from misapplication of the product. Proper valve selection is imperative. Examples of the misapplications or misuse of a valve include but are not 
limited to use in a service in which the pressure/temperature rating is exceeded or in a chemical service incompatible with the valve materials; use of undersized valve actuators; use of extremely 
fast valve actuation and/or continuous valve cycling on standard valves; making modifications of the product of any kind; failure to use caution in operating valves in high temperature, high pressure, or highly hazardous services; and the failure to maintain valves as recommended. The right is reserved to change or modify product design or construction without prior notice and without 
incurring any obligation to make such changes and modification on products previously or subsequently sold.
Figure 3
Printed in USA 11/03