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18
Upon completion, make sure that the fill valve is in the automatic
position and each zone balance and purge or shut off 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 fluid 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
requirements, and maintenance recommendations (pH additive
breakdown, inhibitor reduction, etc.). Carefully figure the
additional friction loss in the system as well as the reduction in
heat transfer coefficients.
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 sufficient flow. 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 flow
throughout the connected boilers.
3. Each connected boiler must have its own circulator pump to
assure adequate flow.
4. Connect DHW (domestic hot water) piping to indirect storage
water heater as shown in Applications.
5. The system flow (secondary loop) must be greater than the boiler's
primary loop flow.
whl-428-r1 Rev. 001 Rel. 012 Date 7.21.20
concentrations,
expansion
Water temperature above 140
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.
o
F requires the circulator pump to run
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