Owner's Manual
37
3.16.3 Coupler Installation
Install both V-couplings, encompassing the
retainer, gasket and sleeve. Do not tighten either
coupling until entire joint has been assembled.
Tighten nuts of 4” couplings to 280-300 inch-lbs.
and 1½” and 2” couplings to 140-160 inch-lbs., or
to a minimum of 1/16” clearance between coupling
lugs, whichever occurs rst. Retightening of the
coupler will be necessary if leakage occurs. A
completed V-coupling installation is shown below.
3.16.4 Special Notes
a) Assembly of gaskets can be made easier by
dipping gaskets in water or wiping them with a
small amount of liquid hand soap. Other rubber
lubricants cannot be used.
b) To simplify installation of the self-restrained
gasket, install the lower half of the gasket rst,
leaving the split area in the steel retaining ring free
at the top. Then, stretch the gasket and split area of
the retaining ring until they slip over the pipe and
into position as shown below.
c) These self-restrained joints are recommended
for use on elbows and tees because they are
capable of supporting end loads caused by internal
pressure up to their rated operating pressure of
80 psi. Recommended assembly torque must be
maintained to withstand these end loads.
d) The gaskets supplied with the ex couplings are
specically formulated for boiler water service
(—20°F to 275°F) and are compatible with
antifreeze and corrosion inhibitors. Use of other
gasket materials is not recommended and may
result in loss of seal!
3.16.5 Laying Length of Coupling
The axial spacing, or gap, between pipe ends joined
by the optional ex couplings is variable within
these limits:
Pipe Size
Laying Length (Gap)
Nominal Max. Min.
1-1/2" 3/4" 1-3/16" 1/4"
2" 1" 1-5/8" 3/8"
4" 2-3/8" 3" 1-3/4"
3.16.6 Misalignment
In addition to the axial misalignment tabulated
in 3.16.5 the ex couplings permit a 4° angular
installation misalignment at each end.
3.17 Installation notes for V-groove couplings.
3.17.1 Pipe End Preparation
a) 4" ends of fabricated manifolds: since the 4" pipe
of the manifold is schedule 10, the ends should be
roll-grooved. DO NOT cut-groove the 4" ends of
the fabricated manifolds.
b) 1½" or 2" laterals of fabricated manifolds: with a
manual pipe cutter, cut 1½" off each of the 4" long
laterals to remove the pipe threads. Do not cut
the threads off the shorter 2½" long lateral, as this
connection is intended to be piped rigid to locate
the manifold during installation. If the manifold
is to be used for parallel pumping, do not cut the
threads off the laterals that are to be capped. The
laterals are schedule 40 so those intended for
V-groove couplings may be roll-grooved or cut-
grooved.
3.17.2 Gasket Material
Selection of a gasket material is of utmost
importance! It must maintain a leak tight seal for
many years at the temperatures and pressures of
a hot water boiler and withstand the attack of the
corrosion inhibitors and antifreezes common to hot
water system. In general neoprene, nitrile, Buna-N,
EPDM, and butyl are not acceptable gasket materials
because they either are not resistant to the uids or
are not capable of continuous use at 250°F.
3.17.3 Gasket and Coupling Installation
Specic installation procedures vary from one
coupling manufacturer to another. Follow the
coupling manufacturer's recommendations for
installation.
3.18 STRAINERS—A start-up strainer is recommended
for practically all modular installations (new and
replacement alike) to prevent system debris and
sediment from ending up in the boilers where it will
inhibit heat transfer and may eventually cause a cast
iron section to crack from overheating.
3.19 OXYGEN CORROSION:
3.19.1 Oxygen contamination of the boiler water will cause
corrosion of the iron and steel boiler components,
which can lead to failure. As such, any system
must be designed to prevent oxygen absorption in
the rst place or prevent it from reaching the boiler.
Problems caused by oxygen contamination of
boiler water are not covered by Burnham's standard
warranty.