State 520 - Manual (Page 31)

Applications
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Page
 In order to purge air in water pipes within a closed‐loop system, an air vent and air
separator should be installed in to the system. Required circulation flow rates are
labeled next to each application diagram. These flow rate requirements must be
followed.
 Toxic chemicals used in boiler treatments such as alcohol, glycerol and glycol groups
must not be introduced into the system if the system incorporates an open‐loop
potable water system.
 The water heater can be used to supply potable water and space heating and shall not
be connected to any heating system or component(s) previously used with non‐potable
water where any chemicals were added to the water heating appliances.
 When the system requires water for space heating at temperatures higher than
required for other uses, a means such as a mixing valve shall be installed to temper the
water for those other uses in order to reduce scald hazard potential.
 Water temperature over 125 F (52°C) can cause severe burns instantly or death from
scalds.
 Chemicals such as diluted Glycol can be used for radiant floor, Hydro/fan coil air or
Baseboard heating only. The diluted solution of glycol must contain between 25 and
55% of Glycol. Be aware that in closed‐loop glycol systems, low pressure in the heat
exchanger can cause low‐temperature boiling, resulting in excessive noise and damage
to the water heater. Consult with the glycol maker for specifications prior to use.
APPLICATIONS
WARNING‐Space‐Heating Applications
* The recirculation pump is to be controlled by:
‐Dual‐set aquastat (recommended w/timer)
OR
‐“Pump Control Connections”. Refer to p24.
* The recirculation pump is to provide no less
than 2 GPM and no more than 4 GPM through
each activated water heater in the system.
‐Recirculation‐
This is a concept drawing only.
Check valve
Check valve
Air
separator
Recirculation
pump
Hot water outlet to fixtures
Air Vent
Unions
Gas supply
Ball valves
Expansion tank
Y‐Strainer
Cold water
inlet
S