18
Series 49
Installation, Operating & Service Instructions
111368-04 - 1/22
7
Steam Piping
NOTICE:
Do not use copper for steam piping for the following reasons:
1. High coefficient of thermal expansion can induce mechanical stresses and cause expansion/ contraction
noises if not accounted for in piping system design and installation.
2. High heat transfer rate (heat loss) of uninsulated copper piping must be included in normal piping and
pickup factors used to size the boiler.
3. Soldering or brazing pastes and fluxes that end up in the system can cause poor heat transfer, surging, an
unsteady water line and wet steam if not thoroughly removed during the skimming procedure.
4. Galvanic corrosion of adjoining metal may occur due to dissimilar metals in certain water
chemistry if dielectric unions are not used.
General Piping Notes
Primary purpose of this near boiler piping is to
separate tiny water droplets from steam exiting
the boiler so that “dry” steam is sent to distribution
system. If near boiler piping is not correct, wet
steam will enter distribution system and the
following problems may occur:
•
Short cycling on low water in boiler
•
Boiler or system flooding
•
Water hammer
•
Failure to heat one or more radiators
Avoid three common piping mistakes shown in
Figure 7-1. This applies even if existing boiler has
one of the piping mistakes shown in Figure 7-1
and appears to be working. If two or more steam
mains must be connected to boiler, connect a
separate take-off for each main into the header
between riser(s) and equalizer. Also note the
following points:
1. A size reduction must be made to connect header
and equalizer. This reduction must be made in the
equalizer line. Do not make this size reduction in
the horizontal header.
2. One pipe steam systems require air vents on
each radiator, as well as at the end of each main.
For system to work properly, these vents must
be properly installed, sized, and be in good
condition. Inspect and replace any defective
vents. If there are no vents at ends of the mains,
install them.
3. For installations with condensate or boiler feed
pumps, follow pump manufacturer’s piping
instructions. Such systems generally do not
require Hartford loops.
4. Do not use a check valve in place of, or in
addition to, a Hartford loop on a gravity return
system.
5. Pipe fill connection from a clean source of water.
When water supply is from a well, make sure that
a strainer is installed in the well system.
WARNING
•
Do not use softened water in steam boilers. Accelerated boiler corrosion will result. Tie in fresh water supply
to boiler upstream of a water softener.
• Oxygen contamination of boiler water will cause corrosion of iron and steel boiler components, and can
lead to boiler failure. Check for and correct system leaks.
!
