Area of use

MMA PVM is used to distribute the flow within different areas in heating and cooling systems.

Description

PVM is a dynamic valve unit developed to regulate pressure drop. A fully open STV mounted on the intake, and a PV differential pressure valve on the return. The pressure-compensating mains control valve ensures problem-free setting of the various mains. The PVM valve is equipped with a signalling circuit, cut-off valve, drain valve and measurement socket as standard. The PVM valve guarantees 100% differential pressure regulation under all conditions, regardless of whether changes are made in the system. The valve regulates the system and removes noise problems due to high pressure drop. After setting the valve no further adjustment to the valves is necessary.

Technical data

Max. temperature
120°C
Min. temperature
-10°C
Material
Brass CW617N
Gaskets EPDM
DN15 DN20 DN25 DN32 DN40 DN50
Flow range. l/h
50- 100- 600- 1000- 3000- 5000-
600 1000 2500 5000 8000 15000
Speed presetting on delivery
DN 15-20 5 turns
DN 25 8 turns
DN 32-50 2 turns
Max. pressure kPa
400 kPa
Min. pressure kPa
5-30 kPa DN15-DN25, 20-80 kPa DN32-DN50
Pressure class
PN16

Dimensions

Dim A B C D E F Weight/kg
PVM 15 167 148 96 86 111 95 2,636
PVM 20 173 151 98 90 114 95 1,991
PVM 25 202 155 102 102 120 96 2,669
PVM 32 235 188 115 120 127 96 4,545
PVM 40 257 206 119 132 139 108 6,055
PVM 50 286 219 126 154 148 111 8,615

 

Capacity

Antal varv DN15 DN20 DN25 DN32 DN40 DN50
1 0,18 0,34 0,48 0,79 1,20 2,00
2 0,32 0,60 0,77 1,32 2,05 3,60
3 0,45 0,83 1,03 1,80 2,80 5,20
4 0,62 1,13 1,50 2,70 4,10 7,60
5 0,86 1,55 2,30 4,10 6,20 11,90
6 1,17 2,10 3,60 5,90 8,90 16,70
7 1,62 2,90 5,00 7,80 12,00 21,20
8 2,55 3,85 6,50 9,70 14,70 25,00
9 3,15 4,50 7,90 11,50 17,10 28,60
10 3,55 5,10 8,80 13,10 19,50 31,50

Preset

The valve is easy to set on the knob using a 4 mm Allen key. The setting is read off the pressure drop diagram for each dimension. When presetting the valve, start by screwing the setting to minimum. Then open the valve to the required value according to the diagram. The STV valve is used solely for shutting off and flow measurement, it must not be set in any position other than open.

The PVM valve is preset according to the diagram. The curves (the oblique lines that indicate the pressure in the main line) are shown in intervals of 5 kPa to make it simple to take a reading. The curves can be moved so that the valve setting can be produced if, for example, 12 kPa is selected in a pipe instead.

Example:
We decide to maintain 12 kPa differential pressure in the main at a flow of 500 l/h (500 l/h comes from the presetting on the radiators). From the point where 12 kPa cuts the horizontal line (flow 500 l/h) a vertical line is taken down to the x-axis. It is then easy to read off that the valve should be set at approx. 7 turns. The minimum pressure drop will then be 1.9 kPa over the valve.

Total pressure drop:
To dimension the pump it will be:
ΔP = ΔPs + ΔPv = 12 +1.9 = 13.9 kPa
Also include the pipe pressure drop from the valve to the pump. The pump can subsequently be adjusted optimally by measuring the differential pressure from PF to P- (ΔP pump). To verify the secondary pressure drop calculated, it can be checked by measuring PF to P+ and the result should then be 12 kPa.

Installation example

Overview of a heating system with 5 staircases with 4 apartments on each one. The critical valve, defined as the valve with the lowest pressure drop as a rule of thumb this will be the valve positioned furthest away from the pump, is used to lower the pump pressure so that the valve achieves the correct pressure. The lowest possible pressure is then obtained in the system. See dimensioning pump pressure.

Standard application

PVM is fitted in the intake, the signal pipe is to be connected at the low pressure side of the STV valve. The valve can be fitted irrespective of whether it is a straight length of pipe. Bends, tubes etc. can be installed immediately after the valve.
1. Flush the system before fitting signal pipe.
2. Install t-pipe with measurement socket on the STV valve.
3. Install signal pipe on the t-pipe and flush to ensure that there is no air in the signal pipe.
4. Install the signal pipe on the PVM valve on the return pipe.

 

Dimensioning

Selecting the right valve in an installation requires some data about the system.
ΔP pump available differential pressure from pump
ΔP load differential pressure for circulation
ΔP STVP pressure drop over valve fully open (diagram)
ΔP PVM pressure drop over the PVM valve (diagram)

Example:
Calculated value for a valve is 0.4 l/s.
50 kPa is available differential pressure for circulation ΔP load 20 kPa is required for the main. We find the minimum differential pressure required for the PVM valve to achieve minimum working pressure in the diagram. Two valves can deliver 0.4 l/s DN25 and DN32.

Adjustment and measuring

When adjusting, the differential pressure on the PVM valve is measured and adjusted to 10 kPa. At least one radiator valve needs to be slightly open. When measuring of the flow use the STV valve and a measuringtool. To be able to measure the flow may the STV valves wheel be set lower to have a higher differential pressure over the STV valve. Note that the differential pressure over the STV valve will not be to high so that the min differential pressure over the PVM valve will be to low and the PVM valve stop to regulate. After the measruing of the flow open the STV valve fully again.Lowering to minimum possible pump differential pressure is carried out by measuring at the PVM valve and obtaining at least 13.2 kPa, this is the pump’s lowest level at which the PVM can be regulated.

 

kv-value the STV valve

 

Numberof turns DN10 DN15 DN20 DN25 DN32 DN40 DN50
1 0,11 0,18 0,34 0,48 0,79 1,20 2,00
2 0,18 0,32 060 0,77 1,32 2,05 3,60
3 0,27 0,45 0,83 1,03 1,80 2,80 5,20
4 0,41 0,62 1,13 1,50 2,70 4,10 7,60
5 0,65 0,86 1,55 2,30 4,10 6,20 11,90
6 1,02 1,17 2,10 3,60 5,90 8,90 16,70
7 1,78 1,62 2,90 5,00 7,80 12,00 21,20
8 2,30 2,55 3,85 6,50 9,70 14,70 25,00
9 2,60 3,15 4,50 7,90 11,50 17,10 28,60
10 2,80 3,55 5,10 8,80 13,10 19,50 31,50

Order designations

Art no. Name Description
9001124 PVM DN15 G15 int. thread
9001125 PVM DN20 G20 int. thread
9001126 PVM DN25 G25 int. thread
9001127 PVM DN32 G32 int. thread
9001128 PVM DN40 G40 int. thread
9001129 PVM DN50 G50 int. thread