IBC VX Series Installation & Operating Manual page 47

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.
These 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 top of the boiler. Relief
valve discharge piping must terminate between 6" (15 cm) and 12" (30 cm) above the floor or per local
code.
Warning
During operation, the relief valve may discharge large amounts of steam and/or hot water.
To reduce the potential for bodily injury and property damage, install a discharge line that:
Is connected from the valve outlet with no intervening valve and directed downward
to a safe point of discharge.
Allows complete drainage of both the valve and the discharge line.
Is independently supported and securely anchored, so as to avoid applied stress on
the valve.
Is as short and straight as possible.
Terminates freely to atmosphere where any discharge will be clearly visible and is at
no risk of freezing. terminates with a plain end which is not threaded.
Is constructed of a material suitable for exposure to temperatures of 375° F or
greater.
Is, over its entire length, of a pipe size equal to or greater than that of the valve outlet
(¾" NPT).
Do not cap, plug or obstruct the discharge pipe outlet.
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3.11 Water Piping