
Data Sheet
Horizontal Distribution Units - HDU Multi-port
Application
Installation Example
Danfoss pre-fabricated HDU distribution units are
made for distribution and measuring of waterbased heating in 2-pipe horizontal systems.
A HDU is easily mounted on the apartment wall
and connected to the riser. The radiators in the
apartment are connected through the manifold.
The unit design provides a good overview of the
installation, which makes after-service easy.
All Danfoss distribution units are equipped with:
heat meter, for individual measuring of en-
▪
ergy consumption.
dP controller, to ensure hydraulic stability in
▪
the heating system.
HDU multi-port units are wall-mounted and created for parallel radiator distribution. HDU multiport units are available with 4 or 7 manifold
ports, each in two versions with left or right connection.
HDU 4-port
- with left connection
HDU multi-port system
Danfoss Heating Solutions VDIGB102 © Danfoss 08/2012 1

Data Sheet Horizontal Distribution Units - HDU Multi-port
Technical Data
Ordering
Max. temperature 90 °C
Max. working pressure in heating system piping before the unit 2 bar
Normal required differential pressure over unit (HDU-SF) 0.26 bar*
Max. differential pressure in a control loop 0.22 bar
Max. static pressure 10 bar (PN10)
Connection to riser (in and out) R ¾"
Connection to manifold (out) ¾"
Power supply (Heat Meter) A-cell battery, 3.6 VDC
*At differential pressure in control loop 10 kPa at
100% AB-PM setting.
HDU-SF Connection Code no.
Horizontal Distribution Unit Single Flat - HDU-SF 4-port left 003L1222
Horizontal Distribution Unit Single Flat - HDU-SF 4-port right 003L1228
Horizontal Distribution Unit Single Flat - HDU-SF 7-port left 003L1225
Horizontal Distribution Unit Single Flat - HDU-SF 7-port right 003L1231
Accessories and Spare Parts Code no.
Manifold port plug (10 pcs.) 003L1246
Capillary tube for AB-PM 003L8152
Filter for strainer 065B8248
Modules for Heat Meter Code no.
M-Bus module 087G6027
Communication
Function
Compression Fittings Data Size Code no.
For PEX tubing
(in accordance with ISO 15875)
For ALUPEX tubing
For steel and copper tubing
Note! Max. flow temperature given by the tube manufacturer must not be exceeded.
L-Bus module (use for external radio) 087G6035
RS232 module 087G6029
RS485 module 087G6032
Analogue output module (4 - 20 mA) 087G6034
Combined module (2 pulse inputs / 1 pulse output) 087G6041
Pulse input module (2 inputs) 087G6037
Pulse output module (2 outputs) 087G6039
16 x 2 mm 013G4156
PN6
G ¾” internal thread
PN10
G ¾” internal thread
PN10
G ¾” internal thread
20 x 2 mm 013G4160
20 x 2.25 mm 013G4093
20 x 2.5 mm 013G4161
16 x 2 mm 013G4186
20 x 2 mm 013G4190
20 x 2.25 mm 013G4093
20 x 2.5 mm 013G4191
16 mm 013G4126
18 mm 013G4128
2 VDIGB102 © Danfoss 08/2012 Danfoss Heating Solutions

Data Sheet Horizontal Distribution Units - HDU Multi-port
Design
Materials in Contact with
Water
1. Ball valve for in- and outlet connection to the
riser.
2. Strainer to trap dirt, sand etc. from pipe water
(replacement filter available as accessory).
3. AB-PM automatic balancing valve, combines
three functions: differential pressure controller,
control valve with linear characteristic and
flow limiter.
4. Manifold for radiator connection, flow.
5. Manifold for radiator connection, return.
6. Automatic air vent and drainage (both inlet
and outlet has drainage and air vent possibilities).
7. Heat Meter for energy measuring, with 8-digit
LCD.
8. Cabinet (with lockable door).
Shut- off valves Body, tailpiece, ball Brass
Seals PTFE
O-ring EPDM
Strainer Body Brass
Filter Stainless steel
O-ring EPDM
AB-PM valve Body, cone (CV), seat (CV) Brass
Membrane, O-ring, seat (PC) EPDM
Spring, cone (PC), screw Stainless steel
Flat gasket NBR
Sealing agent Dimethacrylate Ester
Capillary tube Copper
& 5 Manifold Inlet adapter, shutter, manifold
Air vent & drainage Body Brass
Heat Meter Body of flow meter Brass
Other parts Assembly nipples Brass
pipe, Euro cone connector
O-rings EPDM
Seals EPDM
Temperature sensors, reflectors Stainless steel
Measuring tube qp 0.6 - 2.5 --> PES
Flat gaskets Aramide fibres, NBR
Brass
qp 3.5 - 60 --> PEEK-GF or PPS-GF
Danfoss Heating Solutions VDIGB102 © Danfoss 08/2012 3

ΔP_a
ΔP_a ≥ ΔP_v + ΔP_loop
ΔP_loop
ΔP_loop
ΔP_loop
ΔP_loop
Q [l/h]
ΔP_v
100%
90%
80%
70%
60%
50%
40%
30%
20%
5 6 7
8 9 10
11 12 13 14 15 16 17 18
700
600
500
400
300
200
100
0
Data Sheet Horizontal Distribution Units - HDU Multi-port
Settings
Q = Needed design flow for the loop.
Δ P_loop = Needed design Δ P for the loop.
Δ P_a = available Δ P.
Δ P_V = min needed Δ P for AB-PM (starting Δ PV) = 16 kPa
Flow l/h
Δ P_loop [kPa]
Δ P_loop
[kPa]
20% 30% 40% 50% 60% 70% 80% 90% 100%
5 142 209 294 360 443 509 591 642 684
6 138 201 284 346 424 484 563 611 655
7 134 193 274 331 405 460 534 580 626
8 129 185 263 316 386 435 505 548 595
9 125 177 252 300 366 410 476 516 564
10 120 168 240 285 346 386 447 484 531
11 115 160 228 269 326 361 418 452 498
12 110 151 215 253 305 337 388 420 464
13 104 142 202 237 284 313 359 388 430
14 99 134 189 221 263 288 329 355 394
15 93 125 175 205 241 264 299 322 357
16 87 116 161 188 219 240 269 289 320
17 81 107 146 172 196 216 239 256 282
18 74 97 131 155 174 192 209 222 243
19 68 88 116 138 150 168 179 189 203
20 61 79 100 120 127 144 148 155 162
Flow [l/h] - average
4 VDIGB102 © Danfoss 08/2012 Danfoss Heating Solutions

Data Sheet Horizontal Distribution Units - HDU Multi-port
Example Given:
Design flow trough radiatorsloop: 450 l/h
Pressure drop trough the loop at design flow: 10 kPa
Solution:
Set to 80 %, AB-PM will control differential pressure of 10 kPa when design flow is achieved. It will at any loads including keep it under 22 kPa at zero load, while limiting the
flow to radiator system to 450 l/h.
AB-PM Automatic Balancing Valve
AB-PM is a combined automatic balancing valve. It
features three functions in a compact valve body:
1. Differential pressure controller.
2. Control valve with linear characteristic.
3. Flow limiter.
Benefits:
Reliable heating system resulting in proper
▪
heat distribution even at partial loads and
noise free operation based on stable low Δp
over thermostatic radiator valves even in installation where higher pump head is needed.
Lower heating cost.
▪
Better indoor temperature control • Faster in
▪
simpler installation with less installation space
needed.
Technical data
Nominal diameter DN20
Control valves characteristic Linear
Shut-off leakage rate Acc. to ISO 5208 class A - no visible leakage
CV stroke 2.25 mm
Connection
Ext. thread ISO 228/1 G 1 A
Actuator M 30 x 1.5
Design
1. Spindle.
2. Stuffing box.
3. Pointer.
4. Control valve’s cone.
5. Membrane.
6. Main spring.
7. Hollow cone (pressure controller).
8. Vulcanized seat (pressure controller).
9. Impulse tube.
AB-PM is a combined automatic balancing valve. It is working as Δp controller, flow limiter and zone
controller. Higher pressure acts on the upper side of the control diaphragm (5) while via an impulse
tube (9) lower pressure in the return pipe acts on the lower side of the diaphragm. When available
pressure increases at partial loads, the membrane closes and thus keeps stable Δp inside the controlled loop. Δp controller keeps constant differential pressure on the controlled loop including the control part of AB-PM (similar as if ASV-I would be integrated into ASV-P).
Danfoss Heating Solutions VDIGB102 © Danfoss 08/2012 5
The control part of AB-PM is working as a flow limiter. This enables to set both the design flow as well
as needed Δp. The flow rate is defined by presetting AB-PM, based on pressure demand of the loop.
With actuator mounted on the valve, AB-PM can be used as zone valve. When connected to the room
controller with time programs, functions such as night setback, holiday mode, etc become available.