3-way, threaded, with electric motor
| 3-WAY ZONE VALVES, THREADED, WITH ELECTRIC MOTOR
TYPE: VMR
Materials :
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Operation : All moving parts and the seals of the valve are assembled in a cartridge. O-rings on the outer surface of the piston guarantee a hermetic seal of valve paths. When the valve stem is in its low position, and path B is closed, flow takes place in paths A and AB, passing through the holes in the cylindrical shut-off. When the stem is in its high position the flow in path A is blocked and takes place in paths B and AB. Switchover from one path to the other takes about 6 seconds. Using the manual lever: A lever is positioned on the side of the servomotor that permits manual positioning of the shut-off ball in an intermediate position. The manual lever can only be manoeuvred when it is in its upper position. The valve can be opened by firmly pressing the manual lever both down and in until it locks in the intermediate position. Paths A and B are open in this position. This is useful when filling or emptying the pipeline system or when there is a power failure. |
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Main characteristics : VMR valves are motorised valves used in home applications and small installations to control the flow of hot and cold water. They can be used as shunt or mixing valves in centralised heating or cooling systems. The valve, thanks to its cylindrical shut-off, shunts flow independent from the different pressures between the various paths. This shut-off can have two operating positions depending on how the electric motor that moves is powered. The head of the valve can be removed without opening up the plumbing system: this makes valve maintenance quick and flexible. An auxiliary microswitch can be installed on request and be activated when the valve is switched. Valves have an external lever for manually positioning the shut-off in its central position. Auxiliary switches A two-pole microswitch (M1 version) can be mounted on all versions. The microswitch M1S cannot be installed in versions which do not mount them originally. Electrical connections There are two types of electrical connections depending on the type of low voltage exetrnal control: |
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| * | · two-pole SPDT three-wire external control: when there is a request for hot water the control unit (SPDT) closes the NO contact, the valve closes path B and opens path A. When path A is completely open the cam closes travel limit microswitch C1 and opens travel limit microswitch C2. When the demand for water is satisfied the control closes contact NC, powering the valve through C1 and causing closure of path A. When path A is completely closed the cam closes C2 and opens C1. The valve is now ready for the next request for hot water. |
| * | · single-pole SPST two-wire
external control (2 wires and common): when there is a request for hot
water the control unit (SPST) closes contact N, that powers the relay
which in turn closes the contact NO (microswitch C3).This causes the
closure of path B and opening of path A. When path A is totally open the
cam closes travel limit microswitch C1 and opens microswitch C2. When
the demand for water is satisfied the control opens contact N and
consequently the relay is no longer powered and contact NC (microswitch
C3) is closed. This causes the closure of path A and opening of path B.
When path A is totally closed the cam closes C2 and opens C1. The valve
is now ready for the next request for hot water. |
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Valve identification :
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Overall dimensions:
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1) Application example as 3-way zone valve The zone room thermostat controls opening and closure of the relative VMR valves. When there is no demand it interrupts power to the valve which closes the zone and circulates water back to the boiler return circuit. Installing a meter as illustrated in the diagram permits efficient sharing of operating costs. It is good practice to balance load losses in the recirculation pipeline to avoid excessive flow rate variations in other circuits during valve operation. LEGEND
2) Application example giving priority to the hot water heater We use this installation system mainly on combined boilers to permit the temperature of domestic hot water to be adjusted at the desired value. The valve is used for priority over the heating system. |
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