Crankcase pressure regulator type KVL is fitted in
the suction line ahead of the compressor.
KVL protects the compressor motor against
overload during start-up after long standstill
periods or after defrost periods (high pressure in
evaporator).
For complete list of approved refrigerants,
visit www.products.danfoss.com and search for
individual code numbers, where refrigerants are
listed as part of technical data.
Ordering
Rated capacity 1)
Type
KVL 12
KVL 157.15.36.36.5
KVL 227.15.36.36.5–––
KVL 28
KVL 3517.813.215.916.4–––1 3⁄835034L0052
1
) Rated capacity is the regulator capacity at:
suction temperature ts = -10 °C
condensing temperature tc = 25 °C
pressure drop in regulator Δp = 0.2 bar
To select the product for other conditions or refrigerants, use Danfoss Coolselector®2.
2
) KVL supplied without flare nuts. Separate flare nuts can be supplied:
1⁄2 in / 12 mm, code no. 011L1103
5⁄8 in / 16 mm, code no. 011L1167
R22R134a
7.15.36.36.4
7.15.36.36.4––––12034L0048
17.813.215.916.4–––1 1⁄8–034L0046
17.813.215.916.4––––28034L0051
[kW]
R404A/
R507
R407C[in][mm][in] [mm]
Flare
connection 2)
1
⁄212034L0041
5
⁄816034L0042
Code no.
Solder ODF
1
⁄2–034L0043
5
⁄816034L0049
7
⁄822034L0045
Code no.
The connection dimensions chosen must not be
too small, as gas velocities in excess of 40 m / s at
the inlet of the regulator can result in flow noise.
All Danfoss products fulfill the requirements in REACH.
One of the obligations in REACH is to inform customers about presence of Candidate list substances if
any, we hereby inform you about one substance on the candidate list: an O-ring used in this product
contains Diisopentylphthalat (CAS no: 605-50-5) in a concentration above 0.1% w/w.
DKRCC.PD.HH0.D8.02 | 2
Data sheet | Crankcase pressure regulator, type KVL
Capacity
Max. regulator capacity Qe 1)
Pressure
drop in
Type
KVL 12
KVL 15
KVL 22
KVL 28
KVL 35
1
) The values in the capacity tables refer to the evaporator capacity and are based on
liquid temperature tl = 25 °C
Plant capacity × correction factor = the values in the table
l
DKRCC.PD.HH0.D8.02 | 6
Data sheet | Crankcase pressure regulator, type KVL
Sizing
For optimum performance, it is important to
select a KVL valve according to system conditions
and application.
Valve selectionExample
When selecting the appropriate valve it may
be necessary to convert the actual evaporator
capacity using a correction factor.
This is required when your system conditions are
different than the table conditions.
The selection is also dependant on the
acceptable pressure drop across the valve.
The following data must be used when sizing a
KVL valve:
• Refrigerant
• Evaporator capacity: Qe in [kW]
• Liquid temperature ahead of expansion valve:
tl in [°C]
• Suction temperature ahead of compressor:
ts in [°C]
• Maximum suction pressure after the regulator:
PS in [bar]
• Connection type: flare or solder
• Connection size in [in.] or [mm]
The following example illustrates how this is
done:
• Refrigerant: R404A
• Evaporating capacity: 4.0 kW
• Liquid temperature ahead of expansion valve:
35 °C
• Suction temperature ahead of compressor:
-25 °C
• Maximum suction pressure after the regulator:
3.8 bar ~ -7 °C
• Connectiontype: solder
• Connection size: 5⁄8 in.
Step 1
Determine the correction factor for liquid
temperature tl ahead of expansion valve.
Correction factors for liquid temperature t
tl [°C]101520253035404550
R134a0.880.920.961.01.051.101.161.231.31
R220.900.930.961.01.051.101.131.181.24
R404A/R5070.840.890.941.01.071.161.261.401.57
R407C0.880.910.951.01.051.111.181.261.35
l
From the correction factors table (see below) the
correction factor for a liquid temperature at 35 °C
(R404A) corresponds to a factor of 1.16.
Step 2
Corrected evaporator capacity is:
Qe = 4.0 × 1.16 = 4.64 kW
Step 3
Now select the capacity table for R404A and
choose the column with a suction temperature
of -25 °C.
Using the corrected replacement capacity, select
a valve that provides an equivalent or greater
KVL 12 / KVL 15 / KVL 22 delivers a capacity of
4.6 kW at a pressure drop of 0.2 bar across
the valve and 5.6 kW at a pressure drop of 0.3
bar across the valve. Based on the required
connection size of 5⁄8 in. the KVL 15 valve is the
proper selction for this example.
capacity than required.
Step 4
KVL 15, 5⁄8 in. solder connection:
code no. 034L0049, see ordering table.
Data sheet | Crankcase pressure regulator, type KVL
Design / FunctionKVL
1. Protective cap
2. Gasket
3. Setting screw
4. Main spring
5. Valve body
6. Equalization bellows
7. Valve plate
8. Valve seat
9. Damping device
The Crankcase pressure regulator type KVL opens
at pressure fall on the outlet side, i.e. when the
suction pressure ahead of the compressor drops
below the set value.
The KVL only regulates based on the outlet
pressure. Pressure variations on the inlet side of
the regulator do not affect the degree of opening
since the KVL is equipped with an equalization
bellows (6).
This bellows has an effective area corresponding
to that of the valve seat.
The regulator is also equipped with an effective
damping device (9) against pulsations, which
normally occur in a refrigeration plant.
The damping device helps to ensure long life
of the regulator without impairing regulation
accuracy.
Data sheet | Crankcase pressure regulator, type KVL
P-band and OffsetExample with 4 bar setting
Capacity
Set point
[bar]
Min. setting point
P-band
Adjustment
range
Proportional band
The p-band is defined as the difference between
the pressure at which the valve plate starts to
open (set point) and the pressure at which the
valve is completely open.
Example
If the valve is set to open at 4 bar and the valve
p-band is 2 bar, the valve will give maximum
capacity when the outlet pressure reaches 2 bar.
Offset
Offset
The offset is defined as the difference between
the pressure at which the valve plate starts to
open (set point) and the pressure at which the
valve reaches the necessary opening for the
actual load.
The offset is always a part of the p-band
Because optimal function of a refrigeration plant
is best reached with fully open KVL, the term
offset is normally not used in connection with
the KVL valve.
Danf
already on order pro
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Dimensions and weights
Danfoss
34L05.13
Type
Connection
FlareSolder ODF
H
H
1
2
1
B
C
solder
øD
Net
weight
[in.][mm][in.][mm][mm][mm][mm][mm][mm][Kg]
KVL 12
KVL 15
1
⁄212
5
⁄816
KVL 22––
1
⁄212179 99 6410300.4
5
⁄816179 99 6412300.4
7
⁄822179 99 6417300.4
KVL 28––1 1⁄82825915110520431.0
3
KVL 35––1
⁄83525915110525431.0
oss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products
vided that such alterations can be made without subsequential changes being necessaryeady agreed.