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MECHANICAL SEAL REPLACEMENT
[Start by following steps 1 and 2 of section titled “PUMP REPLACEMENT IN AN EXISTING INSTALLATION”.]
1. Turn off the pump leaving it installed in the line.
2. Ensure electrical power is disconnected and locked out.
3. Close the water supply at the points closest to the pump’s inlet and outlet.
4. Bleed the water pressure from the pump.
5. Place a pan under the pump to collect the drain water.
6. While holding the motor body, unfasten the four bolts that attach the motor to the pump casing (volute). Start with
the two bottom bolts first and remove them, then slowly loosen the top two bolts. Allow the water to drain from the
bottom of the pump. When the water has finished draining, remove the two top bolts. Remove the motor straight
out from the volute being careful of its attached impeller. The motor is heavy, do not drop it!
7. Locate the snap bushing in the centre of the back of the motor housing and pry it out with a screwdriver. Insert a
straight-blade screwdriver into the snap bushing hole and into the slot in the end of the motor shaft to lock the rotor.
8. While holding the rotor (step 7), unscrew the plastic impeller off the motor shaft by hand turning it clockwise (i.e.
opposite to most bolts and nuts!). Place the motor on its back, with its shaft up.
9. Remove the rotary part of the mechanical seal by gently pulling it off the shaft. If too tight use two small flat bladed
screwdrivers. Gently pry it off the shaft by placing the flat side of the blades onto opposite sides of the mechanical seal.
10. Remove the stationary part of the seal by gently prying it off the steel faceplate.
11. Remove any corrosion present on the stainless steel motor shaft with a non-metallic brush or scrub pad. Do not
use a wire brush or steel wool.
12. Install the new stationary part of the seal into the faceplate: first, the rubber cup by firmly pressing it down until it
bottoms, then the ceramic disk. The disk face with a circular groove should be put against the rubber cup (the
visible disk face should be smooth). Press the disk firmly down until it too bottoms into the rubber cup. The
ceramic disk should be clean. If needed, wipe it with alcohol and a soft cloth.
13. Install the new rotating part of the seal by gently pushing it, by hand, onto the shaft (graphite ring first) until its
steel cap stops on the shaft.
Check that:
a) The height of the steel cap over the ceramic disk is between 0.33" and 0.35" (8.4 mm and 8.9 mm). If it is more
than 0.35" (8.9 mm), then try pushing it further down, carefully, but harder.
b) The graphite disk is pressed against the ceramic disk (by a spring inside of it).
If either (a) or (b) is not happening, then contact Armstrong Technical Support:
phone (416) 755-2291 or e-mail [email protected].
14. "Lock" again the motor rotor and shaft as per step 7 above, in order to perform the next step.
15. Fasten the plastic impeller onto the shaft, turning it by hand counter-clockwise until it stops (when it touches the
seal's steel cap). Do not tighten it excessively.
16. Ensure the gasket is properly seated in the pump casing (volute) gasket groove. Holding the motor body, insert
the impeller straight into the volute. Verify the gasket was not dislodged during insertion, and is still seated
properly. Hold the motor body steady while fastening the four bolts that attach the motor to the pump casing
(volute). Tighten evenly and diagonally. There should be a small, even gap of about 0.02" (0.5 mm) all around
between the motor flange and the pump casing (volute).
17. Follow the START UP instructions and check for leaks.
S. A. Armstrong Limited
Armstrong Pumps Inc.
Armstrong Integrated Limited
23 Bertrand Avenue
93 East Avenue
Wenlock Way
Toronto, Ontario
North Tonawanda, New York
Manchester
Canada, M1L 2P3
U.S.A. 14120-6594
United Kingdom, M12 5JL
T: (416) 755-2291
T: (716) 693-8813
T: +44 (0) 8444 145 145
F (Main): (416) 759-9101
F: (716) 693-8970
F: +44 (0) 8444 145 146
© S.A. Armstrong Limited 2010
For Armstrong locations worldwide, please visit
www.armstrongintegrated.com
