danfoss_abqm

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Data sheet

Automatically balanced combination valves

AB-QM

DH-SMT/SI VD.A2.W6.02 Danfoss 10/2006 1

Description

Benefits The AB-QM is able to control the temperature

at low loads and is equally stable all throughthe range.

All changes in the available differentialpressure are corrected by the pressurecontroller. Therefore, less disturbancesfor temperature control and further lessmovements from actuator.

AB-QM offers full flexibility of adjustment AB-QM valves can be set to a precise designvalue they allow full control over the realconditions in the system.

Due to the membrane design the valves arenot susceptible to blockage.

Always the right flow, so no complaints fromendusers or excessive energy consumption

Because the AB valve covers two functions Balancing & Control - the installment costsare halved

Measuring nipples (optional) allowoptimisation of the pumps energyconsumption.

100% built in control valve authority allowslower pump head than traditional setup, thusminimizing energy consumption.

Because of the automatic flow limiting

function, commissioning costs arenonexistent.

Easy adjustability allows late change of designflows without high costs.

Plug and Play even when installation isnot yet completely finished. For examplewhen some floors are already occupiedwhile construction is still going on at otherfloors, the occupied floors are already fullyfunctional and balanced.

Simplifications Flow limitation is achieved by setting the valve

to required flow - Set & Forget. Flow is the only parameter to be considered,

so easy and fast valve selection. Maximal setting of AB-QM corresponds

with the maximal flowspeed through thatpipe dimension according to internationalstandards.

Easy troubleshooting No control ratio calculation No authority calculation Commissioning is a matter of adjusting the

valve without using specialised equipment orhighly educated staff.

Compact design allows instalment whereonly limited space is available, for example instandalone fan-coils.

AB-QM valve is an automatic balancing valve

- flow limiter.

Typical applications are: Automatic (adjustable)

flow limitation on terminal units (fan-coils, chilled

ceilings, Air-handling units..) or branches. It is

recommended to be used in constant flow systems.

AB-QM valve equipped with an actuator is a

control valve with full authority and automatic

balancing valve - flow limiter.

Typical applications are: Temperature control and

permanent automatic balancing on terminal units

(fan-coils, chilled ceilings, Air-handling units..).


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2 VD.A2.W6.02 Danfoss 10/2006 DH-SMT/SI

Data sheet Automatically balanced combination valves AB

Applications - variable flow systems

An AB-QM with an actuator can be used as acombined flow limiter and control valve withfull authority for an AHU (Air Handling Unit). TheAB-QM ensures the required flow on every AHUand simplifies the hydronic balancing of thesystem. Because of the integrated differentialpressure controller the control valve always has100% authority which means that partial loadin the system has no influence on temperatureregulation as it will have with normal controlvalves. By installing AB-QM the whole system

is divided in independent control loop zones

not influencing each other. The flow setting isvery simple. Just set the required flow for theAHU direct at the AB-QM. There is no specialmethod needed for balancing the wholesystems. This means a lot of savings in workinghours. Not to forget the combination of severalfunctions in one valve body means less valvesand installation work. For temperature controlAB-QM can be equipped with different actuators(on/off, 3-point, 0 -10Volt) as required.

Air handling unit (AHU) / fan coil (FCU)

Chilled ceiling

AB-QM in systems with chilled ceilings are usedto achieve the required flow in the system and tocontrol the temperature. An AB-QM is installedat every chilled ceiling limiting the flow. Theintegrated control valve is used for temperature

control by mounting an actuator. Different typesof actuators can be used.


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Applications- constant flow systems

AB-QM can be used as an automatic flowcontroller if a system with an AHU/fan coil is runwith constant flow (system with 3-way valve).

There is no special balancing method needed.The flow can be set directly at the AB-QM.

Alternatively the system can be changed into asystem with variable flow because AB-QM is alsoable to work as a control valve with full authoritywhich means no problems with partial load.

In a one pipe heating system the AB-QM can beinstalled as an automatic flow controller in everyriser. The AB-QM limits the flow to the set value,thus automatically achieving hydronic balance inthe system.

There are numerous applications in which AB-QM can be used. In principle every time you need an automaticflow controller or a control valve with full authorit y it can be used. For example s ystems with heating/cooling

with concrete core activation or small substations.


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TypeComments

Code No.To pipe To valve

Union connection(1 pcs.)

R 3/8 DN 10 003Z0231

R 1/2 DN 15 003Z0232

R 3/4 DN 20 003Z0233

R 1 DN 25 003Z0234R 1 1/4 DN 32 003Z0235

Tailpiece welding(1 pcs.)

Weld. DN 15 003Z0226

Weld. DN 20 003Z0227

Weld. DN 25 003Z0228

Weld. DN 32 003Z0229

Tailpieces for soldering(2 nuts, 2 gaskets,2 soldering nipples

12x1 mm DN 10 065Z7016

15x1 mm DN 15 065Z7017

Locking ring 003Z0236

Shut-off & protection piece (max. closing pressure 16 bar) 003Z0230

Shut-off - plastic (max. closing pressure 1 bar) 003Z0240

Ordering AB-QM

AB-QM DNQmax.

(l/h)Externalthread

Code No. AB-QMExternalthread

Code No.

10 LF 150G A

003Z0251G A

003Z0261

10 275 003Z0201 003Z0211

15 LF 275G A

003Z0252G A

003Z0262

15 450 003Z0202 003Z0212

20 900 G 1 A 003Z0203 G 1 A 003Z0213

25 1700 G 1 A 003Z0204 G 1 A 003Z0214

32 3200 G 1 A 003Z0205 G 1 A 003Z0215AB-QM can not be upgraded to AB-QMwith nipples!

Set-pack (one MSV-M and one AB-QM without nipples)

Type DN Qmax. (l/h)External thread

ISO 228/1Code No.

10 275 G A 003Z0241*

15 450 G A 003Z0242

20 900 G 1 A 003Z0243

25 1700 G 1 A 003Z0244

32 3200 G 1 A 003Z0245* Includes MSV-M DN15 with externalthread G A

Accessories & spare parts

Closing point (measure)

Combinations AB-QM with electrical actuators

Valve type Stroke(mm)

TWA-Z** ABNM-Z AMV 130/AME 01

Recommended ordering code numbers(for details refer to data sheets for these actuators)

082F1226NC, 230 V

082F1094Thermal actuator24 V (0 - 10 V)

082H8036AMV 130/24 V,24 s/mm,3-point control

082F1072Adapter for AB-QM(M30 x 1.5)

082H8003AME 01/24 V,24 s/mm,0 - 10 V

AB-QM DN 10 - 20 2.25

AB-QM DN 25 - 32 4.50 * *

* up to 60 % of Q max** Please be aware that only this type of TWA actuator is to be used with AB-QM

Closing pressure for all actuators: 6 bar.

10.4

0.3


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Technical dataNominal diameter DN 10

Low Flow10 15

Low Flow15 20 25 32

RangesQmin (20%)Qmax (100%)

l/h30 55 55 90 180 340 640

150 275 275 450 900 1700 3200

Diff. pressure (p - p) 0.16 - 4.0 bar; (16 - 400 kPa) 0.2 - 4.0 bar

Pressure stage PN 16

Control range > 1:50

Control valves characteristic Linear

Leakage acc. to standard IEC 534 max.0.01 % of k v

at 250 N

Flow mediumWater and water mixtures with secondary coolants (like glycols)*for closed heating and cooling systems

Medium temperature C -10 ... +120

Stroke mm 2.25 4.5

Connection external thread (ISO 228/1) G G G G G 1 G 1 G 1

actuator M30 x 1.5

Material In the water Valve bodiesMembranes and O - ringsSpringsCone (Pc)Seat (Pc)Cone (Cv)Seat (Cv)ScrewFlat gasketSealing agent(only for valves with measuring nipples)

Brass (CuZn40Pb2 - CW 617N)

EPDMW.Nr. 1.4568,W.Nr. 1.4310W.Nr. 1.4305EPDMCuZn40Pb3 - CW 614NCuZn40Pb2 - CW 617NStainless Steel (A2)NBRDimethacrylate Ester

Out of the water Plastic partsInsert parts and outer screws

POMCuZn39Pb3 - CW 614N;W.Nr. 1.4310; W.Nr. 1.4401

Operation principle The AB-QM is a control valve combined with adifferential pressure controller. The differentialpressure controller maintains a constant pressureover the control valve independent of varyingconditions in the installation. Because of thisconstruction the flow is automatically limited toa specified value and the control valve has anauthority of 100%.

Flow limitationIf you have a constant differential pressure acrossan orifice with a known resistance (kv value) youcan determine the flow with the formula:

pkQ v

Because the AB-QM limits the differentialpressure (p) across the control valve to aconstant level it follows that the flow throughthe AB-QM is also limited.To function properlythe AB-QM needs a pressure difference of atleast 16 kPa. By limiting the stroke of the controlvalve, the maximal flow through the valve can beadjusted.If the kv-value of the control valve is halved, theflow is also halved. Because the AB-QM has anearly linear chracteristic to have half the flowyou need half the stroke (see figure 1).

100%

80%

50%

Q,Kv50% 80% 100%

STROKE

* according suitability and usage especially in not oxygen tight systems please mind the instructions given by the coolant

producer


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Operation principle(continued)

AuthorityThe valve authority can be defined as: Theresistance across the fully opened control valve,divided by the total resistance in the system(valve, pipes, heat exchanger etc.).

systemvalve

valve

RR

RA

Usually the authority should be 0,3 (30%) ashigh as possible to guarantee sufficient controlquality. The resistance in the sytem is variablebecause it depends on the flow. If the flowis reduced, the resistance in the system alsodrops. Normally the control valve would have tocompensate for this by closing even further, thuscausing a distortion in the valve characteristic.Because the AB-QM has a built in differentialpressure controller that keeps the differentialpressure across the control valve constant, the

effect of this decrease is compensated. It istherefore possible to assume that Rsystem iszero. The formula then becomes:

%1001valve

valve

R

RA

The AB-QM therefore always automaticallyensures 100% authority which provides stablecontrol and therefore increase confort and savestime consuming calculations to check the valveauthority.

As an example we take two valves in anormal HVAC system, one close to the pump(position 1) and the most distant valve (position2). Both valves have the same differentialpressure potential (the pump head) but the

pressure drops between:- Control valve (abrivated as CV),- balancing valve (abrivated as BV) and- other elements (abrivated as OT; such as pipe,

terminal units ect.)are distributed differently. With the valve closerto the pump the pressure drop in the pipes(OT) is much smaller. The differential pressurecontroller (BV) ensures however that the workingconditions for both control valves (CV) are thesame.

If we look at a situation where we need only20% , can see that the pressure drop in thepipes (OT) becomes smaller when the flow is

decreasing.This effect is much bigger for thedistant valve because the pressure drop inthe pipes (OT) is bigger to begin with. Thedifferential pressure controller (BV) compensatesfor the difference and ensures identical workingconditions for both control valves across thetotal range. If you compare that with a situationwith traditional balancing valves you can seethat, because the balancing valve is static anddoesnt react to the system conditions, thepressure drop across the control valve increasessignificantly which puts the control valve (CV)to a challenge to provide comfort and stabletemperature control.

position 2

position 1

pressure drop in a s ystem with A B-Q M pressure drop in a system with traditional valve set(manual balancing valve + control valve)

P

Q

CV

BV

OT

P

Q

CV

BV

OT

20% ofdesign flow

Designflow

20% ofdesign flow

Designflow

position 1 position 2P

Q

CV

BV

OT

P

Q

CV

BV

OT

20% ofdesign flow

Designflow

20% ofdesign flow

Designflow

position 1 position 2


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Design

1. Differential pressure controller BV

The differential pressure controller maintains aconstant differential pressure across thecontrol valve.The pressure difference (p2-p3)on the membrane is balanced with the forceof the spring. Whenever the differential pressureacross the control valve changes (due to achange in available pressure, or movement ofthe control valve) the hollow cone is displaced toa new position which brings a new equilibriumand therefore keeps the differential pressure at aconstant level.

2. Control valve CV

The control valve has a linear characteristic. Itfeatures a stroke limitation function thatallows adjustment of the Kv value. Thepercentage marked on the scale equals thepercentage of 100% flow marked on the pointer.Changing the stroke limitation is done by liftingthe blocking mechanism and turning the top ofthe valve to the desired position, showed on thescale as a percentage. A blocking mechanismautomatically prevents unwanted changing ofthe setting.

1

2

3

4

5

6

7

8

1. Stuffing box2. Spindle

3. Plastic ring4. Control valves cone5. Membrane6. Main spring7. Hollow cone

(pressure controller)8. Vulcanized seat

(pressure controller)

P2-P3

P1-P3

P1 P2P3

Function:

The AB-QM valve consists oftwo parts:1. Differential pressure

controller2. Control valve


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Sizing Example 1: Variable flow system

Given:Cool requirement per unit : 1000 WFlow temperature in the system: 6 C

Return temperature in the system:12 C

Required - control and balancing valves:AB-QM and actuators type for BMS system.

Solution:Flow in the system: Q (l/h)Q = 0,86 x 1000 / ( 12-6 ) = 143 l/h

Selected:AB-QM DN 10 mm with Qmax = 275 l/hpresetting on 143 / 275 = 0,52 = 52 % ofmaximum opening.Actuators: AMV 01 - 24 V

Remarks:required minimum differential pressure acrossthe AB-QM DN 10 - 16 kPa.

Example 2: Constant flow system

Given:Cool requirement per unit : 4000 WFlow temperature in the system : 6 CReturn temperature in the system : 12 C

Required - automatic flow limiter:AB-QM and presetting.

Solution:Flow in the system : Q (l/h)Q = 0,86 x 4000 / ( 12-6 ) = 573 l/h

Selected:AB-QM DN 20 mm with Qmax = 900 l/hpresetting on 573 / 900 = 0,64 = 64 % ofmaximum opening.


Example 3: Sizing AB-QM according pipedimension

Given:Flow in system 1, 4 m3/h (1400 l/h = 0,38l/s),

pipe dimension DN 25 mm

Required - automatic flow limiter:AB-QM and presetting.

Solution:In this case we can selected AB-QM DN 25 mmwith Qmax = 1700 l/h

In this case it will be recommended to checkthe maximum velocity in the pipe. For this wecalculate velocity in the pipe for condition:DN 25 mm Di 27,2 mm

Dimension and condition acceptable, veloscity

below 1,0 m/s.

Preseting on the valve AB-QM DN 25 mm1400 / 1700 = 0,82 = 82 % of maximum opening.


500

1500

1000

2000

2500

3000

3500

5590

180

275340

450640

900

1700

3200

0

DN10 DN15 DN2 0 DN2 5 DN3 2

Q[l/h]

DN15LF

30

150

DN10LF


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Pump optimising / Troubleshooting

The AB-QM features measuring nipplesthat allow measuring of the pressure difference(p2-p3) across the control valve. If the pressuredifference exceeds certain value (7-14 kPa) itmeans the differential pressure controller isoperational and the flow limitation is achieved.

The measuring function can be used to verify if

enough pressure difference is available and thusverify the flow.

It can also be used to optimize the pump head.The pump head can be decreased until no morethan the minimal required pressure (7-14 kPa)is available on the most distant valve (in termsof hydronic). This optimal point is to be foundwhen proportionality between pump head andmeasured differential pressure cease to exist.

Verifying the pressure can be done by using aDanfoss PFM 3000 for example (for more detailsplease refer to AB-QM Tech Notes VN.A3.N1.02).

P2-P3

Blue

Red

P2-P3

P1-P3

P1 P2P3

Presetting The calculated flow can be adjusted easilywithout using special tools.To change the presetting:- Remove the blue protective cap or the

mounted actuator.- Raise the grey plastic ring and turn to the new

presetting.- Release the white plastic ring and the

presetting is locked.

The presetting scale indicates a values from100% flow to 0% closed.

Counter clock wise turning would increase theflow value while clock wise would decrease it.

When valve is set to 80% or more the red ring(below DN max flow sign) becomes visible.

If the valve is a DN 15 then the max flow= 450 l/h =100% presetting. To set a flow of 270l/h you have to set: 270/450 = 60%.

Danfoss recomends a presetting/flow from 20%to 100%. Factory presetting is 100%.

90

6070

80

40

50

(%)

30

20100

90

6070

80

40

50

(%)

30

20100

90

6070

80

40

50

(%)

30

20100

90

6070

80

40

50

(%)

30

20100

Red

100% 10%


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Service The valve features a service function that allowschanging of the stuffing box (code 065F0006)under water pressure.Valves are equipped with plastic shut-offmechanism that is to be used for isolating

function up to 1 bar differential pressure. Whenclosing against higher differential pressureplease use accessory - shut-off & protectionpiece (003Z0230) or set the value to 0%.

Unwanted change of the setting is provided bylocking ring (code 003Z0236) which is insertedin the groove below the scale. The locking ringwould not allow one to lift the grey plastic ringthus no change of the setting is possible.

Installing AB-QM valve is mono-directional meaning that

the valve operates when arrow on the valve body

is aligned with flow direction. When this rule is

disobeyed the valve acts like variable orifice that

cause water hammer at sudden closing when

available pressure has increased or valve have

been set to lower value.

In case when system condition allows backflowsit is strongly recommended to use backflow

preventer in order to avoid possible water

hammer that can damage the valve as well as

other elements in the system.


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Dimensions

Type L1mmL2

mmL3

mmH1

mmH2

mmH3

mmH4

mmb

ISO 228/1Weight

kg

AB-QM DN 10 53 36 79 20 73 105 140 G A 0.38

AB-QM DN 15 65 45 79 25 75 110 145 G A 0.48

AB-QM DN 20 82 56 79 33 77 115 150 G 1 A 0.65

AB-QM DN 25 104 71 79 42 88 130 165 G 1 A 1.45

AB-QM DN 32 130 90 79 50 102 145 180 G 1 A 2.21

TWA-Z AMV / AME


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Danfoss A/SComfort DivisionHrupvnget 11Hrup

DK-8600 SilkeborgDenmarkTel.: +45 74 88 80 00Fax: +45 74 88 81 00

http://www.hydronicbalancing.com

Danfoss Trata d.o.o.Joeta Jame 16, P.O.B. 48201210 Ljubljana - entvidSlovenia

Tel.: +386 1/58 20 200Fax: + 386 1/51 99 824

http://www.danfoss-trata.si

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