Installation
26
│
Page
PUMP
CONTROL
MODES
The
T
‐
H2
‐
DV/T
‐
H2
‐
OS
provides
the
four
types
of
the
pump
control
modes.
The
pump
control
modes
are
selected
by
changing
dipswitch
settings.
The
dipswitches
that
change
the
pump
control
modes
are
located
in
the
right
bank
of
dipswitches
in
the
upper
‐
left
quadrant
of
the
computer
board
in
the
T
‐
H2
‐
DV/T
‐
H2
‐
OS.
(See
right.)
These
4
modes
only
affect
pumps
that
are
connected
to
the
T
‐
H2
‐
DV/T
‐
H2
‐
OS
pump
control
(p.25)
A)
Recirculation
Control:
No.
5
ON
Feature:
Maintaining
temperature
in
a
standard
recirculation
loop,
providing
hot
water
in
a
quicker
amount
of
time.
Function:
The
pump
is
only
set
to
run
when
the
temperature
of
the
water
in
the
recirculation
loop
is
more
than
9°F
below
the
set
temperature
of
the
T
‐
H2
‐
DV/T
‐
H2
‐
OS.
The
pump
will
run
for
about
1
minute
every
30
minutes
to
determine
whether
the
water
temperature
in
the
entire
recirculation
loop
is
more
than
9°F
below
the
set
temperature.
If
the
water
temperature
is
more
than
9°F
below
the
set
temperature,
the
pump
will
remain
running
until
the
water
in
the
loop
reaches
the
set
temperature.
Otherwise,
the
pump
will
stop
for
another
30
minutes.
If
the
inlet
thermistor
of
water
heaters
detects
that
the
water
temperature
is
more
than
9°F
below
the
set
temperature
before
those
30
minutes
have
elapsed,
the
pump
will
activate
immediately
and
remain
running
until
the
water
in
the
loop
reaches
the
set
temperature.
B)
Storage
Tank
Circulation
Control:
No.6
ON
Feature:
This
is
to
ensure
a
higher
rate
of
recovery
for
storage
tank
applications.
Function:
The
T
‐
H2
‐
DV/T
‐
H2
‐
OS
heats
the
water
5.4°F
higher
than
its
set
temperature.
The
circulation
pump
between
the
storage
tank
and
the
water
heater
will
continually
remain
running.
After
set
temperature
has
been
reached
in
the
storage
tank,
the
T
‐
H2
‐
DV/T
‐
H2
‐
OS
will
fire
off
and
limit
the
water
flow
rate
to
less
than
2.6
GPM,
to
continually
monitor
the
temperature
throughout
the
system.
Note:
In
this
mode,
the
pump
will
continually
remain
running.
C)
Energy
Conserving
Recirculation:
No.5
and
No.6
ON
Feature:
Operates
similarly
to
the
standard
Recirculation
Control
mode,
but
saves
more
energy
by
limiting
the
temperature
within
the
recirculation
loop.
Function:
The
temperature
of
the
recirculation
loop
is
never
kept
above
120°F
(49
°C),
regardless
of
the
set
temperature
of
the
T
‐
H2
‐
DV/T
‐
H2
‐
OS.
Right
bank
of
dipswitches
