IBC SL Series Installation & Operating Manual page 48

To use legacy heat, we recommend water flow after burner shutdown. There can be significant
build-up of energy due to the volume of heated water in the system. Default load settings 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 settings will run the Load 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. To
guard against deadheading pumps when all zone valves are closed, set the load Pump Post
Purge (sec) to '0'.
To allow pump purge after burner shut-down, the primary pump must be under the control of the
boiler.
To simplify the control application, promote good loads and flow management, installers must
conform to the piping design configurations provided.
Propylene glycol usage
Warning
Do not use automotive-type ethylene or other types of automotive glycol antifreeze, or
undiluted antifreeze of any kind. This may result in severe boiler damage. Installers
must ensure that glycol solutions are formulated to inhibit corrosion in hydronic
heating systems of mixed materials. Improper mixtures and chemical additives may
cause damage to ferrous and non-ferrous components as well as non-metallic, wetted
components, normally found in hydronic systems. Ethylene glycol is toxic, and may be
prohibited for use by codes applicable to your installation location. For environmental
and toxicity reasons, IBC recommends only using non-toxic propylene glycol.
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. Generally, a 50%:50% solution of propylene glycol and water requires an increased
system circulation rate (gpm up 10%), and system head (up 20%) to provide performance
equivalent to straight water.
IBC boilers are designed for use within a closed loop, forced circulation, low pressure system. A
30 psi pressure relief is supplied for field installation in the relief valve fitting on the boiler. For the
SL 40-399 G3, optional relief valves up to 75 psi can be used where required on closed loop
systems within multi-level buildings. Relief valve discharge piping must terminate between 6" (15
cm) and 12" (30 cm) above the floor or per local code.
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Section: Installation