LP-428 Rev. 6.6.16
18
For installation that incorporates standing iron radiation and
systems with manual vents at the high points, follow previous
section and, starting with the nearest manual air vent, open
until water ows out. Then close vent. Repeat procedure,
working your way toward the furthest air vent. It may be
necessary to install a basket strainer in an older system where
larger amounts of sediment may be present. Annual cleaning of
the strainer may be necessary.
Upon completion, make sure that the ll valve is in the automatic
position and each zone balance and purge or shut o is in an
open position and zone valves are positioned for automatic
operation.
K. Freeze Protection Fluids
Use only inhibited glycol solutions which are specially
formulated for hydronic systems. Ethylene glycol is toxic and
can attack gaskets and seals used in hydronic systems. Glycol
mixtures should not exceed 50%.
1. Glycol in hydronic applications is specially formulated for this
purpose, and includes inhibitors that prevent the glycol from
attacking metallic system components. Make certain that the
system uid is checked for the correct glycol concentration and
inhibitor level.
2. The glycol solution should be tested at least once a year and
as recommended by the glycol manufacturer.
3. Anti-freeze solutions expand more than water. For example:
A 50% by volume solution expands 4.8% in volume for a
temperature increase from 32oF to 180oF, while water increases
3% over the same temperature rise. Allowances must be made
for this expansion in the system design.
4. A 30% mixture of glycol will result in a BTU output loss of 15%
with a 5% increase in head against the system circulator.
5. A 50% mixture of glycol will result in a BTU output loss of 30%
with a 50% increase in head against the system circulator.
It is highly recommended that you carefully follow the glycol
manufacturer’s recommended concentrations, expansion
requirements, and maintenance recommendations (pH
additive breakdown, inhibitor reduction, etc.). Carefully gure
the additional friction loss in the system as well as the reduction
in heat transfer coecients.
L. Zoning with Zone Valves
1. When zoning with zone valves, connect the boiler to the
system as shown in Applications. The primary/secondary
piping shown ensures the boiler loop will have sucient ow.
It also avoids applying the high head of the boiler circulator to
the zone valves.
2. Connect DHW (domestic hot water) piping to indirect
storage water heater as shown in Applications.
M. Zoning with Circulators
1. When using circulator zoning, connect the boiler to the
system as shown in Applications. NOTE: The boiler circulator
cannot be used for a zone. It must only supply the boiler loop.
2. Install a separate circulator for each zone.
3. Connect DHW (domestic hot water) piping to indirect
storage water heater as shown in Applications.
N. Multiple Boilers
1. Connect multiple boilers as shown in Applications.
2. All piping shown is reverse return to assure balanced ow
throughout the connected boilers.
3. Each connected boiler must have its own circulator pump to
assure adequate ow.
4. Connect DHW (domestic hot water) piping to indirect
storage water heater as shown in Applications.
5. The system ow (secondary loop) must be greater than the
boiler’s primary loop ow.
Water temperature above 140
o
F requires the circulator
pump to run continuously and water hardness between 5
and 7 grains. Hardness above 7 grains will damage the heat
exchanger and shorten the service life of the boiler.
water ow out the hose. If zone valves are used, open the
valves one at a time manually. (NOTE: You should check
the valve manufacturer’s instructions prior to opening
valves manually, so as not to damage the valves.)
• Manually operate ll valve regulator. When water runs
out of the hose, you will see a steady stream of water
(without bubbles). Close balance and purge valve or drain
to stop the water from owing. Disconnect the hose and
connect it to next zone to be purged.
• Repeat this procedure for additional zones (one at a
time).
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