Freestyle 2 Series - Recirculation (if Used)

Part number 550-142-950/0122
37
FreeStyle
®
series 2 wall mount gas-fired water boiler – boiler manual
Figure 47 Suggested pipe sizing for system headers
and zone piping — RESIDENTIAL with
baseboard, convectors or cast iron radiators
ONLY (20°F temperature rise)
Model System header
FS-80/120 1” or larger
FS-155 1-1/4” or larger
Recommendations are based on a 20°F temperature drop
through the system.
Suggested maximum load per zone
Copper pipe and
baseboard size
Maximum recommended
feet of baseboard
¾” 67
1” 104
Size zone circulators to handle the required ow and head
loss for each zone.
17 Install water piping (continued)
Recirculation (if used)
Massachusetts code applications require
recirculation piping or heat-traced piping if the
distance from the water heater to the furthest xture
exceeds 100 feet.
Maintaining domestic water
temperature in the supply piping
1. Recirculation is used to reduce wait time for water use, to
minimize hot water and energy waste caused during the waiting
period, and to prevent degradation of the system supply water
temperature. ASPE recommends recirculation when the distance
from the water heater to the furthest xture exceeds 100 feet or
the time lag for hot water to reach a xture(s) exceeds 30 seconds.
2. Consult local codes and American Society of Plumbing Engineers
(ASPE) Domestic Water Heating Design Manual - latest edition,
for further information.
Recirculation pump (Figure48,page38, item 9)
1. Little ow is required to maintain a temperature in the piping.
2. Size of circulator depends on minimum ow requirements of the
tempering valve.
3. Minimum ow rates of the tempering valve must be main-
tained.
Aquastat (Figure48,page38, item 10)
1. Used to control the on-o position of the circulator. Aquastat
is set 5° to 10° lower than mixed water outlet of the mixing
valve (item 7).
2. e circulator cannot run continuously as bypass through
the mixing valve will eventually allow the temperature on
the piping to climb to the water heater temperature during
draw periods.
Check valves (Figure48,page38, item 8)
1. Assure the ow of water in one direction.
2. Each check valve functions as follows:
a. prevent bypass in the event of pressure drop.
b. prevents thermal siphoning of hot water to the cold water
supply.
c. prevents ow of cold water to the tempered water supply.
A draw of tempered water will not result in ow of cold
water into the return loop.
Controls
1. Aquastat to enable domestic recirculation pump.
2. When using a recirculation set-up, it cannot be constant
circulation (never go to heating) and the Control Parameter
P14 change from 0 to 1.
Domestic water supplied to xtures that could
pose an injury hazard due to high temperature,
such as showers and faucets, should be equipped
with a temperature regulating device, such as an
anti-scald mixing valve.
Expansion tank (Figure48,page38, item 11)
THERMAL EXPANSION TANK — If a backow
preventer, check valve, or pressure reducing valve is
piped on cold water inlet of water heater, you must
install an expansion tank on cold water supply line
to prevent normal thermal expansion from
repeatedly forcing open T&P relief valve.
e T&P relief valve is not intended for constant
duty, such as relief of pressure due to repeated
normal system expansion. Refer to expansion
tank manufacturer’s instructions for proper siz-
ing.
Failure to comply could result in severe personal
injury, death or substantial property damage.