Data sheet
AB-PM DN 40-100
VD.HR.D1.02 | 5
© Danfoss | 2018.01
Δp
v
Δp
r
=P
0
-P
1
Δp
a
=P
0
-P
3
003L8151
Flow verification /trouble
shooting
To verify that an installation functions per the
design specifications the AB-PM (DN 40-100) has
test plugs that allow measuring of the pressure
difference Δp
r
or Δp
cv
across the valve. In this
way the pressure difference and flow can be
verified for handover or troubleshooting.
At handover of the base building when the HVAC
design conditions are specified but components
are not yet installed in the zone, the differential
pressure and flow for the valve and loop can
only be verified by installing a bypass with the
same dp as specified for the zone. For quick hand
over, without flow verification, the calculated dp
can be pre-set on the valve for the dp and flow
demand of the loop.
In the 2
nd
stage of commissioning when the
HVAC system has been installed in the zone, the
differential pressure and flow can be verified for
handover and troubleshooting.
The differential pressure can be measured using
the following methods:
DPCV: Measure differential pressure from AB-PM
to installed partner valve (Δp
r
=p
0
− p
1
).
PIBCV: Measure the differential pressure across
the control valve (ΔP
cv
=p
1
− p
2
).
To calculate the flow below formulas are used:
DPCV:
Δp
r
=p
0
− p
1
Q=kv
cv
× √∆p
r
PIBCV:
Δp
Cv
=P
1
− P
2
Q=kv
cv
× √∆p
cv
For kv
cv
values see datasheet “AB-QM flow
checker DN 40-250”
For trouble shooting the available pressure can
be verified, Closing the AB-PM valve fully and
measuring p
0
– p
2
.
Verifying the pressure and flow can be done
by using Danfoss PFM or other dp measuring
devices (select valve type: AB-QM)
Q = needed design flow for the loop
Δp
r
= needed differential pressure for the loop
Δp
v
= differential pressure on AB-PM
Δp
a
= min. needed differential pressure over
both AB-PM and loop
Δp
a
= Δp
v
+ Δp
r
Δp
V
=
p
1
− p
3
Δp
r
=
p
0
− p
1
(as DPCV)
Δp
cv
=
p
1
− p
2
(as PIBCV for flow validation)
Δp
a
= p
0
− p
3
P
1
-P
3
P
1
-P
2
P
0
-P
1
P
0
P
2
P
3
P
1
Flow
direction
Differential pressure legend
Sizing
AB-PM is to be sized based on the needed flow
(Q) and the needed differential pressure drop for
the zone (∆p
r
).
Max flow /Δp
r
for all sizes are presented in the
sizing guide in fig. 5.
When pipe dimension has been selected, specific
sizing, selection and setting can be identified
based on Q and Δp
r
in fig. 6-10.
Alternatively table 1-5 can be used for AB-PM
sizing as well.
For needed flow and differential pressure
outside specified in graphs and tables, setting
can be calculated by linear distribution of
setting.
For minimum needed available differential
pressure (Δp
a
) at Q nominal see table 6.
Fig. 4 Differential pressure legend