Rheem Raypak Delta Limited 399B - Hydronic Heating

Cold Water Run
Cold water run di󰀨ers from cold water start in that
the system water entering the heater remains below
105ºF (41ºC) continuously. Typically, this is the case
in swimming pool heating and water source heat
pump applications as well as some others. If the
system water is kept in a narrow temperature range,
a permanent manual bypass can be employed and
manually adjusted to achieve an inlet temperature of
105ºF (41ºC) or higher. An injector pump arrangement
may also be utilized to keep the heater loop at or
above 105ºF (41ºC). An injector pump approach has
the added value of being able to adjust to changes in
the system water coming back to the heater take-o󰀨.
Table G: Heater Rates of Flow and Pressure Drops
Notes: 1. Basis for minimum ow: Models 399–899, 20 gpm or 40°F ∆T. Models 989–2339, 30 gpm or 40°F ∆T.
Basis for maximum ow: Models 399–899, 90 gpm. Models 989–2339, 132 gpm.
2. Flow switch will not operate if ow is less than 20 gpm.
Temperature & Pressure Gauge
The temperature and pressure gauge is factory-mount-
ed in the in/out header.
Hydronic Heating
Pump Selection
In order to ensure proper performance of your heater
system, you must install a correctly sized pump. Ray-
pak recommends using a 20°F ∆T as design ∆T. (∆T is
the temperature di󰀨erence between the inlet and outlet
water when the heater is ring at full rate). If a ∆T of
larger than 20°F is necessary, see Table G and Table
H for ow rate requirements.
Model
No.
10°F ∆T 20°F ∆T 30°F ∆T Min. Flow Max. Flow
gpm ∆P (ft) gpm ∆P (ft) gpm ∆P (ft) gpm ∆P (ft) ∆T gpm ∆P (ft) ∆T
399B 67 5.5 34 1.4 22 0.6 20 0.5 34 90 10.0 7
499B 84 9.1 42 2.3 28 1.1 21 0.6 40 90 10.4 9
649B 55 4.1 36 1.8 27 1.1 40 90 10.8 12
749B 63 5.7 42 2.6 32 1.5 40 90 11.3 14
899B 76 8.3 50 3.8 38 2.2 40 90 11.7 17
989B 83 5.2 55 2.3 42 1.3 40 132 13.1 13
1259B 106 9.6 71 4.3 53 2.4 40 132 14.8 16
1529B 129 15.7 86 7.1 64 4.0 40 132 16.5 19
1799B 101 10.7 76 6.0 40 132 18.3 23
1999B 112 13.8 84 7.9 40 132 19.0 25
2069B 116 14.8 87 8.5 40 132 19.0 26
2339B 132 21.4 98 12.1 40 132 21.4 30
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