Page 20
SECTION 6 WATER
CONNECTIONS
6.A Water Piping
NOTE:
This boiler must be installed in a closed
pressure system with a minimum of 12 psi (82.7kPa)
static pressure at the boiler.
Section 6.D on page 21 shows typical plumbing
installations. Be sure to provide unions and isolation
valves at the boiler inlet and outlet so it can be isolated
for service. Check local codes for specific plumbing
requirements before beginning the installation.
An ASME pressure relief valve is supplied with these
boilers, and is pre-set at 30 PSI. The valve outlet
piping should be discharged to a drain and must be
piped to discharge near the floor. It cannot have a
threaded end at its termination point nor be of a closed
circuit design.
A pressure reducing valve (automatic feed) must
be used to maintain the system at constant proper
pressure. Supply properly installed purge valves to
eliminate air from each circuit.
A drain valve is installed on the lower right side of the
boiler and is used for draining the unit for service. If
the boiler is being drained so that it will be left in a
space that may freeze, it is critical to remove the two
lower plugs from the left side of the heat exchanger.
See Section 9.E on page 40 This is the only way to
ensure all the water is out of the heat exchanger.
Be sure at least one air elimination device is installed
in the system to eliminate trapped air from the system.
Hot water piping should be supported by suitable
hangers or floor stands, NOT by the boiler. Due
to expansion and contraction of copper pipe,
consideration should be given to the type of hangers
used. Rigid hangers could transmit noise through the
system caused by the piping sliding in the hangers.
A properly sized expansion tank must be included in
the system.
6.B Oxygen Permeable Systems
This boiler must not be directly connected to a heating
system utilizing oxygen permeable tubing. Provide a
water-to-water heat exchanger between systems to
prevent corrosion of ferrous metals such as the boiler’s
piping, wet walls, etc. Air elimination devices are not
sufficient protection and corrosion damage is not
covered under the limited warranty.
6.C
Anti-freeze
Non-toxic HVAC anti-freeze may be added to the
hydronic system provided the concentration does not
exceed 50%, and the anti-freeze contains an anti-
foaming agent and rust inhibitor. Follow the anti-freeze
manufacturer’s recommendations for yearly or biannual
replacement of system anti-freeze. Never use toxic
automotive anti-freeze in a boiler system.
The use of an anit-freeze will reduce the heat transfer
capabilities of the water.
NOTE: The use of an anti-freeze will reduce the heat
transfer capabilities of the water.
NOTE: Not all manufacturer supplied pumps are
capable of maintaining the reduced temperature rise
required with glycol concentrations greater than 35%.
If glycol concentrations required are greater than 35%
a field supplied pump should be used.
CAUTION
Different glycol products may provide varying degrees
of protection. Glycol products must be maintained
properly in a heating system, or they may become
ineffective. Consult the glycol specifications, or
the glycol company, for information about specific
products, maintenance of solutions, and set up
according to your particular conditions.
NOTE: The minimum return water temperature of
the unit, in order to avoid condensation in the vent,
is 130°F. The unit's control is equipped to protect
against low temperatures, however the pumps must be
installed and wired properly for this feature to function.
The system pumps must be wired to the system pump
terminals, and a boiler pump must be installed and
wired to the boiler pump terminal (models 125 - 200
are built with LLH / boiler pump systems that are wired
at the factory). See Figure 28 on page 27. If the
system is not setup this way, condensation may occur
which could damage venting systems.
LAARS Heating Systems
