Raypak 992C, Installation & Operating Instructions Manual

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H models: MIX TYPE = VALVE
Heating Systems, where the inlet water temperature
remains below 105°F (41°C) must have cold water
protection . Known protection methods consist of mix-
ing heated outlet water with the inlet water using a
bypass to raise the inlet to 105°F (41°C) or higher.
Once the system is heated up and has return water
temperatures of 105°F (41°C) or higher, the mixing of
outlet water with inlet water is no longer needed and
the bypass can be shut off. If the bypass is not shut off
as the system heats up, the outlet temperature may
continue to climb and trip the high limit, thereby shut-
ting down the heater. Thus an automatic valve system,
such as a three-way proportional valve to control the
bypass, should be used. The integrated VERSA IC
®
control system provides automatic functionality to con-
trol a proportional 3-way valve to provide Cold Water
Protection for Single or Cascade configurations. See
Fig. 9.
H models: MIX TYPE = PUMP
H models include a second option for individual Cold
Water Protection method (“PUMP”). MIX TYPE =
PUMP uses a Variable Speed Pump as a CWP mech-
anism recommended for those systems that require
low-lead/non-ferrous plumbing. Applications that
require a working setpoint over 150°F must use an H
model with a storage tank. See Figs.10,11 and 12.
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CAUTION: Damage due to internal condensation
may occur if the heater inlet water temperature does
not exceed 105°F (41°C) within 7 minutes of start-
up. Warranty claims will be denied for damage or
failures caused by condensation.
Fig. 9: CWP-Hydronic Single-Boiler (BOIL 3-way)
Mode 1
*Maximum 4 times the pipe diameter or 12”, whichever is less.
Fig. 11: Low Temp Process - Open Loop: H model,
Single with Storage Tank
Fig. 10: H - Hydronic - Single Boiler with CWP (VS
Pump - MIX TYPE = 2)