1-23
INSTALLATION
SL 80-399 MODULATING GAS BOILER
SL 26-260 G3, SL 40-399 G3 MODULATING GAS BOILERS
BOILER HEAD LOSS
BOILER HEAD LOSS SL 26-260 G3
Flow rate (gpm)
6
10
15
20
25
Head @ flow (ft wc)
2’
3.5’
5.5’
8’
13’
Table 5A: Boiler Head Loss
BOILER HEAD LOSS - SL 40-399 G3
Flow rate (gpm)
20
25
30
35
40
45
Head @ flow (ft wc)
1
1.5
2
3
4
6
Table 5B: Boiler Head Loss
Ensure that 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 the actual performance by measuring Δ°T (under high
and low flow conditions) after establishing the correct firing rate.
We require water flow after burner shutdown to utilize legacy heat – this is significant
due to the mass of the heat exchanger plus its 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 15 minutes after burner shutdown
(for the last calling load). As shipped, the default software will run the Load 1 pump for 5
minutes to place the legacy heat where it is useful. Any secondary pump can be set to run
for 0 – 900 seconds in the heat purge mode. Guard against deadheading pumps when all
zone valves are closed (see Section 2.7 Set Up & Load Definition).
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, 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.
Propylene glycol solution is commonly used in a closed loop where freeze protection is
required. Its density is lower than that of water, resulting in lower thermal performance at a
given flow and pressure. As a rule of thumb, a 50%:50% solution of propylene glycol and
water will require an increased system circulation rate (gpm up 10%), and system head
(up 20%) to provide performance equivalent to straight water.
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 77°F (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.
