Sequence Of Operation Two-Stage Units; Well Water Systems - Bosch TA025 Installation And Maintenance Manual

Well Water Systems

figure 8: Heater Package Compatibility
Model Heater Model
TA025 thru 035 HP050-1XS
TA049 thru 071 HP050-1XM
TA025 thru 035 HP075-1XS
TA049 thru 071 HP075-1XM
TA025 thru 035 HP100-1XS
TA049 thru 071 HP100-1XM
TA049 thru 071 HP150-1XM
HP150-1XM
TA049 thru 071 HP200-1XM
HP200-1XM
All heaters rated single phase 60 Hz, and include unit fan load. All fuses type "D" time delay or HACR type breaker or
HRC FORM 1. Wire size based on 60 deg. C copper conductors.
SeQuenCe of oPerATIon–
TWo STAGe unITS
(Figure #13 Wire Schematic)
CoolInG Mode
Energizing the "O" terminal energizes the unit
reversing valve in the cooling mode. The fan motor
starts when the "G" terminal is energized. Note that
the fan motor will take 30 seconds to ramp up to
operating speed and will run at fan only rated air
flow as long as there is no call for compressor or
heater operation.
When the thermostat calls for first stage cooling (Y1)
the loop pump or solenoid valve if present is
energized and the first stage of compressor capacity
starts. The fan ramps up to first stage cooling air flow
in 30 seconds.
When the thermostat calls for second stage cooling
(Y2) the second stage (or full compressor capacity)
is initiated. The fan ramps up to full cooling air flow.
Once the thermostat is satisfied, the compressor
shuts down accordingly and the fan ramps down to
either fan only mode or off over a span of 30 seconds.
Note that a fault condition initiating a lockout
will de-energize the compressor irrespective
of which stage is engaged.
Revised 03-11
KW Heater Amps
208V 240V
4.8 17.3 20.0
4.8 17.3 20.0
7.2 23.6 30.0
7.2 23.6 30.0
9.6 34.7 40.0
9.6 34.7 40.0
14.4 52.0 60.0
14.4 34.7 40.0
17.3 20.0
19.2 69.3 80.0
19.2 34.7 40.0
34.7 40.0
Subject to change without prior notice
Circuit MCA
208V 240V
L1/L2 27.1 30.4
L1/L2 27.1 30.4
L1/L2 34.9 42.9
L1/L2 35.7 43.8
L1/L2 48.8 55.4
L1/L2 49.5 56.3
SINGLE 71.2 81.3
L1/L2 49.5 56.3
L3/L4 21.7 25.0
SINGLE 92.9 106.3
L1/L2 49.5 56.3
L3/L4 43.4 50.0
HeATInG Mode
The first two stages of heating (Y1 & Y2) operate in
the same manner as cooling, but with the reversing
valve de-energized. On a call for auxiliary heat (W1),
the fan ramps up to auxiliary heat air flow
immediately and the electric heater package is
energized along with the compressor. As the
thermostat is satisfied, the heaters will shut off as
soon as W1 is de-energized, and the compressors
will remain on until the thermostat stages are
satisfied. Note that if the unit compressor lock out
for any reason at this time, the electric heaters will
continue to function normally.
Once the thermostat is satisfied, the compressor
shuts down and the fan ramps down either fan only
mode or off over a span of 30 seconds. If emergency
heat (W2/EM) is called for, the fan will ramp up to
emergency heat air flow immediately and the heater
package will energize in emergency heat mode, all
heater elements coming on. On shut down the fan
will ramp down over a period of 30 seconds.
Well WATer SYSTeMS
(Figure #10)
Copper is adequate for ground water that is not high in
mineral content. Should your well driller express concern
regarding the quality of the well water available or should
6 720 220 046
11
TA Series
Max. fuse AWG
Min.
208V 240V
30 30 8
30 30 8
40 45 8
40 45 8
50 60 6
50 60 6
80 90 4
60 60 6
25 25 10
100 110 2
50 60 6
45 50 6