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AVTQ Flow-Compensated Temperature Controller
Brand: Danfoss
AVTQ is a self-acting flow-compensated temperature controller primarily for use in district heating systems with plate heat exchangers for instantaneous hot water production.
It closes on rising sensor temperature. It has permanent no-load (idle) temperature setting on about 40° C which is offset by a pilot valve using flow-compensation principle during tapping. Tapping temperature can be set individually.
AVTQ prevents high temperatures in the heat exchanger when no hot water is tapped by rapidly shutting off the heat supply (e.g. hot district heating water).
AVTQ can be used with most plate heat exchangers. However, the heat exchanger manufacturer should be contacted to ensure that the chosen heat exchanger has been approved for use with the AVTQ.
- Pressure-controlled opening/closing on start/stop tapping
- Infinite adjustment of operating temperature
AVTQ controller consist of a thermostatic actuator, diaphragm element, main valve and pilot valve.
Thermostatic actuator with diaphragm element and main valve are installed on the district heating (primary) side. The diaphragm element is, via impulse tubes, connected to the pilot valve on the domestic hot water (secondary) side.
Specifications
Brand
BSP Connection
- G 1” Male
- G 3/4” Male
Capillary Length
- 3.28 feet (1 metre) - Capillary Tube
Cone Material
- Dezincification Resistant Brass BS 2874 - Valve: Temperature Controller
- PPS Plastic - Pilot Valve
Diaphragm Material
- 316L Stainless Steel Sreel (CrNi Steel, DIN 17440, W.No. 1.4435) - Diaphragm Housing
- EPDM
Differential Pressure
- psi: 87.02 (kPa: 600, bar: 6) - Max.
Enclosure / Body Material
- Bronze
- Dezincification Resistant Brass
Flange Size - 1/2” (DN 15)
- 1/2” (DN 15) - PN 10
- 1/2” (DN 15) - PN 16
Flow Rate
- 1.6 m³/hour (Kvs)
Gasket Material
- EPDM - Sensor
Materials of Construction
- 316L Stainless Steel (CrNi Steel 1.4404, DIN 17440) - Pressure Relief Cylinder
- Dezincification Resistant Brass BS 2874 - Sensor Stuffing Box
- Dezincification Resistant Brass BS 2874 - Valve Base: Pilot
- EPDM - Valve Plate: Temperature Controller
Measuring Range
- pH: 7 to 10
Media
- Circulation Water - Main Valve
- Domestic Hot Water (Chlorine Content, Max.)
- Glycolic Water up to 30 % - Main Valve
Nominal Pressure
- psi: 145 (kPa: 1,000, bar: 10) - Pilot Valve
- psi: 232.1 (kPa: 1,600, bar: 16) - Main Valve
O-Ring Material
- EPDM - Pilot Valve, Temperature Controller
Operating Temperature - Sensor
- 130° C (266° F) - Max.
Process Temperature
- 2° to 100° C (35.6° to 212° F) - Medium
Ratio
- 100:1 - Control
Seat / Seal Material
- 316L Stainless Steel (CrNi Steel 1.4404, DIN 17440) - Valve Seat
Sensor / Probe Material
- Copper
Spindle Material
- 316 Stainless Steel (CrNi Steel 1.4401, DIN 17440)
- Dezincification Resistant Brass BS 2874 - Diaphragm: Temperature Controller
Spring Material
- 631 Stainless Steel (CrNi Steel 1.4568, DIN 17440)
- PPS Plastic - Spring Retainer
Temperature Range
- 45° to 60° C (113° to 140° F) - Setting Range Xs
- District heating systems
