Desuperheater (Optional) - Econar GeoSource Vara GV Series Installation And Operating Instructions Manual

XV.
DESUPERHEATER
(OPTIONAL)
A
GeoSource
Vara
heat
pump equipped with
a
desuperheater can
provide
supplemental heating
of
a
home's domestic hot water. This is
done
by
stripping
heat
from
the superheated gas
leaving
the
compressor and
transferring
it
to
a
hot water
tank. A
desuperheater
pump,
manufactured
into
the
unit, circulates water
from
the
domestic hot water tank, heats
it
using
a
double walled
water-to-refrigerant
heat exchanger, and
returns
it
to
the
tank. The desuperheater
provides supplemental heating
because
it only
heats
water when
the
compressor is
already running to heat or cool the conditioned
space.
Because the desuperheater
is
stripping
some
of
the
energy
from
the heat
pump
in
order to heat the water, the heat
pump's capacity
in
the
winter
will
be
slightly
less than
a
unit without
a
desuperheater.
During
extremely
cold
weather, or
if
the heat
pump
cannot keep
up
with
heating
the space, the desuperheater
fuse may
be
pulled in order
to get more capacity out
of
the unit.
Insulated copper tubing should
be used
to run from
the
hot water tank to
the desuperheater
connections on
the
left
side
of
the
unit.
The
built
in
desuperheater
pump
can
provide
the
proper
flow
to
the desuperheater
ifthe
total
equivalent length
of
straight pipe
and connections is kept
to
a
maximum
of
90 feet
of
1/2-inch type
L
copper tubing.
This tubing
can be connected to the hot water tank
in
two
ways:
METHOD
1
Using a desuperheater
tee installed
in
the
drain at
the
bottom of the water heater
(See Figure
6).
This is
the
preferred method for
ease
of installation, comfort
and
efficiency.
The tee eliminates
the need
to tap into
the
domestic hot
water lines
and eliminates household water
supply temperature variations that could occur
from
connectins to
the hot water
pipes.
METHOD
2
Taking hot
water
from
the
bottom drain
and
returning
it
to
the
cold water supply
line (See Figure
7).
This method
maintains
the same comfort
and
efficiency
levels but
increases installation time
and
costs.
This method
requires
a
check valve in
the return line to
the
cold
water
supply
to
prevent water
from flowing
backwards through
the desuperheater when
the
tank is
filling.
Water passing
through
the
pump backwards
damages the rotor,s
bearing,
which
reduces
pump
life
and causes
noise problems in
the
pump. A
spring-type check
valve with
a
pressure
rating
of
1/2
psi or
less is
recommended.
All
air must be
purged from
the desuperheater
plumbing
before
the
pump is engaged. To purge small
amounts
of
air
from
the
lines, loosen the desuperheater
pump from its
housing
by turning
the brass
collar.
Let water drip orlt
of
the
housing
until flow is established,
and
re-tighten
the
brass
collar.
Using
1/2-inch copper tubing from
the
tank
to the desuperheater
inlet
is
recommended to keep water
velocities
high, avoiding air pockets
at the
pump inlet.
An air vent in
the
inlet line
can
also
help
systems
where
air is
a
problem.
If
one
is
used
(we recommend
a
Watts
Regulator brand
FV4
or
Spirovent) mount
it
near the
desuperheater
inlet roughly
2-l/2
inches above the
horizontal
pipe.
Shutoffvalves allow
access
to
the
desuperheater
plumbhg without
draining
the
hot water
tank.
Keep valves open when pump
is
running.
VC,IUTION:
Running
the desuperheater
pump without
water
flow will
damage the
pump.
Poor water
quality
may resffict
the
effectiveness of using
the desuperheater
tee
by plugging
the entrance
with
scale
or buildup from
the
bottom of
the tank,
restricting
water
flow.
Desuperheater
maintenance includes periodically
opening the drain on
the
hot water tank
to
remove
deposits.
Ifhard
water,
scale, or
buildup
causes
regular
problems in hot water
tanks
in your
area,
it
may result in
a
loss
of
desuperheater
effectiveness. This
may require
periodic
cleaning with Iron
Out
or similar products.
The
desuperheater's
high
temperature cutout switch
is
located
on the return line from
the
water heater.
The
switch is
wired
in
series
with
the desuperheater pump to
disable
the
pump from circulating
at
entering water
temperature above 140"F. Ifthe
desuperheater
causes
tank temperatures
to
become uncomfortably
hot, this
temperature switch
can be moved to
the leaving water line
which
will
reduce the tank
maximum
temperafures
lOoF
to
l5'F.
Do not remove
the
high temperature switch
or
tank temperatures could become dangerously high.
A
fuse is attached to
the fuseholder and must
be
inserted in
the fuseholder after
the desuperheater
is
operational.
Do
not insert fuse until
water
flow
is
available or
the
pump may
be damaged. Remove
the
fuse
to
disable
the
pump if
the desuperheater
is not in
operation.
18