Armstrong CD72SR User manual

CD72SR
Control Disc Steam Trap
Installation and Operation Manual
IOM-31-V1.0-EN
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these instructions

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2
General Safety Information ........................ 3
Product Information ..................................... 3
Product Installation ...................................... 4
Maintenance Requirements ...................... 5
Trouble Shooting ......................................... 11
Repair Parts ................................................... 12
Table of Contents

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1
General Safety Information
This document should be used by an experienced person as a guide for installing the Armstrong
CD72SR Control Disc Steam Trap. Selection or installation of equipment should always be
accompanied by competent technical assistance. You are encouraged to contact Armstrong
International Inc., or its local sales representative for additional information.
Product Information
Armstrong CD72SR is a disc styled trap designed to control the trap’s cycle rate. The reduced
cycle rate provides Armstrong CD72SR trap with a longer service life than typical disc traps. This
enhanced performance ensures minimum maintenance time and reduced steam costs.
The capacity of Armstrong CD72SR has been engineered specically for the following
applications: large steam main drips, process equipments and HVAC heating equipments at
constant pressure.
Armstrong CD72SR is available in socket weld and screwed connections (anged connections
on request) for the maximum operating pressure range of 600psig@ 486°F (41.4 barg @ 252°C)
and in 1/2”, 3/4” and 1” (DN15, DN20, DN25) sizes.
Note:
• Minimum pressure for satisfactory operation is 5 psig (0.34 barg).
• Maximum back pressure should not exceed 80% of the inlet pressure. If back pressure
exceeds 80% of inlet pressure, the trap may not shut. At 50% to 70% back pressure traps
may become unstable. Therefore, Armstrong suggests limiting back pressure to 50% of inlet
pressure.
Product Installation
1. Before installing the trap, blow down the piping that leads to the trap’s inlet. Use full line
pressure. Be sure that the maximum operating pressure (PMO) of the trap is adequate for the
installation. (The PMO is stamped on the nameplate).
2. Install the trap inlet below the liquid level of the equipment to be drained. Make inlet piping as
short as possible. Use a minimum number of elbows and other restrictions in inlet and outlet
piping. Install a dirt pocket in the line ahead of the trap.
3. To allow for maintenance, install a valve on each side of the trap and a downstream testing
tee (unless test valve is used as the downstream valve). All valves should be full ported type to
avoid restricting ow.
4. If possible, install the trap in the horizontal position. For freeze-resistant applications, inlet
piping must be pitched towards the pipe for gravity ow. Additionally, the trap must be installed
vertically, discharging downward. Discharge piping must be self-draining.

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4
Maintenance Requirements
Wear progresses simultaneously on both the disc and the seating surfaces. Simply replacing the
disc is not sucient to repair a disc trap; both disc and seat must be renewed. In cases of minor
wear causing cycling, the disc may be replaced but the seat surfaces must also be lapped and/
or cleaned again to near atness. If a trap’s seat wear is deeper than .01 (0.25), it has progressed
beyond the depth of the hardened seat surface of most disc traps. If the seat is lapped at, the
softer material is exposed, and additional service life will be shortened. Theoretically the seats
may be lapped or machined, however, any alteration of the internal components of any disc trap
can change its operating characteristics. Armstrong does not recommend re-lapping the seating
area of the Series CD Controlled Disc Traps.
Seat and Disc replacement procedure
CAUTION: This set of instructions is for a complete replacement of repair kit including
cap. It may be noted that, during disassembly of the cap, the cap threads may get
damaged and may not seal properly as intended during reassembly. In such case, the
existing cap needs to be replaced with a new cap.
Please refer to torque requirements for sealing the cap in step no.10 of the “Seat and
Disc replacement procedure”.
DISASSEMBLY
1. Ensure that the pressure has been safely relieved and the trap is cooled out. Secure the trap
rmly with a vise with the cap facing upward.
2. Loosen the cap and unthread it by hand.

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3. Gently remove the seat, disc, three alignment pins and the inner gasket.
4. If the trap is to be rebuilt, inspect the top surfaces of the body (highlighted below) for steam
cutting, nicks, gouges or any other visible signs of damage. Also inspect the exposed
threads of the body for any damage.
Inspect surfaces

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REASSEMBLY
1. Firmly secure the trap body with a vise and exposed threads facing upwards.
2. Gently clean the surfaces on the seat and the body (as shown in pictures below) with a soft
damp cloth. Inspect the surfaces for any nicks, gouges or any other visible signs of damage.
CONTENTS OF REBUILD KIT
CAP - 1 NO.
(with name-plate embedded)
DISC - 1 NO. SEAT - 1 NO.
ALIGNMENT PINS - 3 NOS. INNER GASKET - 1 NO.
Clean and inspect surfaces

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3. Apply anti-seize paste to the cap threads on the body.
4. Place the alignment pins (3 nos.) and the inner gasket in th body as shown below:
5. Place the seat on the top of the body as shown below. Ensure that the alignment pins line up
with the holes in the bottom of the seat. Note that, when placed over the pins, the seat should
be free to move and small gap be visible between the seat and the body.
Anti-seize paste

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6. Gently clean the surface with a soft damp cloth as shown below. Inspect the surfaces fro any
nicks, gouges or any other visible signs of damage.
7. Place the disc on top of the seat. The groove in the disc should be facing downwards. Ensure
that the disc is centered on the seat.
8. Apply anti seize paste to the inside of the cap on the surface, spread out evenly. Do not
apply any other lubricant on the surface.
Clean and insect the surface.
Apply anti-seize paste

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1
9. Slowly slide the cap over the seat and disc. Gently thread the cap down by hand until it stops
and tighten it. Gently shake the trap and look for sound of disc moving inside the cap. Now
proceed to the next step. If the disc cannot be heard moving inside the cap, it may be caught
between the cap and the seat. Slowly remove the cap, recenter the disc on the top of seat and
gently re-tighten the cap by hand. Repeat this procedure until the disc can be heard moving
inside the cap.
10. Using a manual torque trench, tighten cap to 220lb-ft (300N-m). Never use an impact tool.
Troubleshooting
Problem Causes Solution
Steam Loss 1. Control disc damage
2. Seat damaged
Replace it.
No Condensate
Discharge.
1. Dirt or sediment in screen.
2. Screen damaged and scale lodged in
the passage.
3. Control disc or seat damaged.
1. Blowdown by pipe plug.
2. Replace the screen and
clean the passage.
3. Replace it

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10
Repair Parts
To order for replacement of Control disc, Seat and Screen please specify the model details and the
size of the trap. For further assistance contact Armstrong representative.
The repair components and their respective part numbers are listed in the table below:
Model Size Control
Disc
Seat Gasket Cap Dowel
Pin
Name
plate &
screw
Screen Retainer Plug
CD72SR
1/2”
3/4”
1”
(DN15,
DN20,
DN25)
D96002 D96003 A8906 D96001
D96004
(3 nos.
per
piece)
D10932
&
A6091
A22290 D9198 D13834
Repair
Kit D107738 Not applicable

Limited Warranty and Remedy
Armstrong International, Inc. or the Armstrong division that sold the product (“Armstrong”) warrants
to the original user of those products supplied by it and used in the service and in the manner for
which they are intended, that such products shall be free from defects in material and workmanship
for a period of one (1) year from the date of installation, but not longer than 15 months from the
date of shipment from the factory, (unless a Special Warranty Period applies, as listed below). This
warranty does not extend to any product that has been subject to misuse, neglect or alteration after
shipment from the Armstrong factory. Except as may be expressly provided in a written agreement
between Armstrong and the user, which is signed by both parties, Armstrong DOES NOT MAKE
ANY OTHER REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, BUT NOT
LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR ANY IMPLIED WARRANTY OF
FITNESS FOR A PARTICULAR PURPOSE.
The sole and exclusive remedy with respect to the above limited warranty or with respect to any
other claim relating to the products or to defects or any condition or use of the products supplied by
Armstrong, however caused, and whether such claim is based upon warranty, contract, negligence,
strict liability, or any other basis or theory, is limited to Armstrong’s repair or replacement of the
part or product, excluding any labor or any other cost to remove or install said part or product, or
at Armstrong’s option, to repayment of the purchase price. As a condition of enforcing any rights
or remedies relating to Armstrong products, notice of any warranty or other claim relating to the
products must be given in writing to Armstrong: (i) within 30 days of last day of the applicable
warranty period, or (ii) within 30 days of the date of the manifestation of the condition or occurrence
giving rise to the claim, whichever is earlier. IN NO EVENT SHALL ARMSTRONG BE LIABLE FOR
SPECIAL, DIRECT, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING, BUT NOT
LIMITED TO, LOSS OF USE OR PROFITS OR INTERRUPTION OF BUSINESS. The Limited Warranty
and Remedy terms herein apply notwithstanding any contrary terms in any purchase order or
form submitted or issued by any user, purchaser, or third party and all such contrary terms shall be
deemed rejected by Armstrong.
Armstrong International
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IOM-31-V1.0-EN
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