IBC SL 35-199 Operating Instructions Manual page 25

WARNING
Water quality has a significant
impact on the lifetime and
performance of an IBC Boiler
heat exchanger.
Improperly prepared water in
a heating circuit may cause
damage to the heat exchanger
through corrosion or fouling.
Repeated or uncontrolled
water fills will increase the
potential for damage.
High levels of dissolved
solids or minerals may
precipitate out of the fluid
onto the hottest part of the
heat exchanger, impairing
heat transfer and resulting in
overheating and premature
failure. The amount of solids
that may form on the heat
exchanger will depend on
the degree of hardness and
the total water volume in the
system. A high water volume
system with a low hardness
count may cause as much
damage as a system with less
volume and higher hardness,
so it is recommended to treat
water so as to remove all
dissolved solids. Other water
chemistry allowable limits are
as follows:
•
Acidity pH is to be between
6.6 and 8.5
•
Chloride is to be less than
125 mg/l
•
Iron is to be less than 0.3
mg/l
•
Cu less than 0.1 mg/l
•
Conductivity is to be less
than 400μS/cm (at 25°C)
•
Hardness is to be 7 Grains
or less
IMPORTANT: Ensure that
these limits are acceptable
for the other water-side
components in the system.
INSTALLATION
SL 35-199, SL 45-260 MODULATING GAS BOILERS
The minimum flow rate required through the heat exchanger is 6 USgpm with a
maximum of 25 USgpm allowed. Primary/Secondary piping ensures adequate
flow and de-couples Δ°T issues (boiler vs. distribution). Aim for a 20° to 30° F Δ°T
across the heat exchanger at high fire (there is a boiler protection throttle fence
limiting the Δ°T to 40°F).
The SL Series modulating boilers are designed to supply four different heating
loads with temperatures within the range 34°F to 185°F - to meet four separately
piped loads. Use closely spaced tees to connect each pumped "load" (e.g. DHW,
baseboards or radiant floor) to the primary loop, or employ the use of a hydraulic
separator to isolate the boiler loop from the system and pipe the system from
the secondary side of the separator. Two-load systems may be piped with a
variant of parallel piping commonly used, including our unique dual side piping
configuration.
Always ensure that loads sensitive to high temperatures are protected using
means such as a mixing valve set for maximum limit (say 140°F) to protect
radiant floors, or an aquastat (wired to the boiler's auxiliary interlocks).
Ensure the pump is rated for the design circulating water temperatures; some
pumps have a minimum water temperature rating above the low temperature
potential of the boiler. Following installation, confirm actual performance by
measuring Δ°T (under high and low flow conditions) after establishing the correct
firing rate.
A variety of application drawings showing basic design options are available from
the IBC web site at: www.ibcboiler.com
BOILER HEAD LOSS SL 35-199, SL 45-260
Flow rate (gpm) 6
Head @ flow (ft wc) 2'
Table 5: Pressure Vessel Head
We recommend water flow after burner shutdown to utilize legacy heat – this is
significant due to the mass of the heat exchanger (60 Lbs) plus its 20L internal
water volume. Default software values will run the boiler's primary pump for up
to 5 minutes (300 seconds) after burner shutdown. Secondary pumps can be
set to run up to 5 minutes after burner shutdown (for the last calling load). As
shipped, the default software will run the Boiler pump for 5 minutes to place the
legacy heat where it is useful. Any secondary pump can be set to run for 0 – 300
seconds in the heat purge mode. Guard against deadheading pumps when all
zone valves are closed.
The primary pump must be under the control of the boiler to allow pump purge
after burner shut-down.
Schematics for several piping layouts are provided herein, and additional
drawings are available at www.ibcboiler.com. Installers shall conform the piping
design to one of the provided configurations to simplify the control application,
promote good loads and flow management.
10 15 20 25
3.5' 5.5' 8' 13'
1-19