Danfoss AVTQ DN 15 Data sheet

Data sheet

Flow-compensated temperature controller

AVTQ DN 15

Description 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.

Main data:

• DN 15

• kVS 1.6

• PN 16 - Main valve

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.

PN 10 - Diaphragm element and pilot valve

• Suitable for domestic hot water (DHW) production in range of 45 … 60 °C

• Permanent no-load (idle) temperature (approx. 40 °C)

• Temperature (primary):

- Circulation water / glycolic water up to 30 %: 2 … 100 °C

• Connections:

- Ext. thread (weld-on and thread tailpieces)

• Return mounting

Ordering

Example: Flow-compensated temperature controller, DN 15, kVS 1.6, PN 16, setting range 45 … 60 °C, t

100 °C, ext. thread

max

- 1× AVTQ controlle r, 45 … 60 °C Code No: 00 3 L70 15

Option:

- 1× Weld-on tailpieces Code No: 003H690 8

The controlle r package (code 003 L7 015) does not inclu de copper impulse tubes . Two standard Ø6 × 0.8 mm copp er tubes, of the l enght required for the particula r application, must be obta ined separately by th e customer in order to instal the produ ct. The compression fittings f or mounting the tubes onto the controller are p rovided in the package.

AVTQ controller

Picture

* Controller incl. gla nd and compression fitt ings for mounting on Ø6 × 0.8 mm co pper impulse tube (standard cop per impulse tube not

included in th e package).

(mm)

15 1.6 G ¾ A

(m3/h)

Main valve ISO 228/1 Pilot valve ISO 228/1

Connection

G 1 A

(DN 20)

Code No .*

003L7015

Accessories

Picture Type designation DN Connection Code No.

Weld-on tailpieces

External thread tailpieces

Conical ex t. thread

acc. to EN 10226-1

– 003H6908

R ½” 003H6902

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Data sheet Flow-compensated temperature controller AVTQ DN 15

Ordering (continuous)

Technical data

Service kits

Picture Type designation Code No.

Gasket for diaphragm housing 003L 3154

Thermostatic actuator incl. sensor stuff ing box 003L7100

Compression fittings for Ø6 mm copper tube (4 ferrules and 4 nuts) 003 L7101

Pilot valve excl. compression fittings 003 L7108

Main valve incl. complete valve insert 00 3L7109

Diaphragm element excl. compression fittings 003 L7111

Sensor stuffing box incl. gasket

Nominal diameter DN 15

kVS value m3/h 1.6

Control ratio 100 : 1

Cavitation factor z ≥ 0.6

Leakage acc. to standard IEC 534 < 0.05 %

Nominal pressure

Max. differential pressure

Max. closing pressure 12

bar

Medium

Medium pH Min. 7, max. 10

Medium temperature °C

Connections

valve Ext. thread

tailpieces Weld-on and external thread

Setting range Xs °C 45 … 60

Time constant T acc. to EN 14597 s 4

Max. adm. temperature at sensor °C 130

Max. water velocit y around the sensor m/s 1.5

Capillary tube length m 1

Materials

Valve body RG5, DIN 1705, W.no. 2.1096.01

Valve insert and valve cone

Valve seat, pressure relief cylinder CrNi steel, DIN 17440, W.no. 1.4404

Temperature controller

Valve spindle CrNi steel, DIN 17440, W.no. 1.4435

Valve plate, O-ring, diaphragm EPDM

Diaphragm housing CrNi steel, DIN 17440, W.no. 1.4435

Diaphragm plate CrNi steel, DIN 17440, W.no. 1.4436

Diaphragm spindle

Diaphragm housing stuffing box

Housing

Spindle CrNi steel, DIN 17440, W.no. 1.4401

Sensor

Sensor stuffing box EPDM

Gasket Carbon dioxide (CO2)

Charge

Valve body

Valve base

Pilot valve

Valve spindle CrNi steel, DIN 17440, W.no. 1.4401

Setting spring CrNi steel, DIN 17440, W.no. 1.4568

Cone, spring retainer PPS-plastic

O-ring EPDM

Valid for primary side (main valve)

Valid for secondar y side (pilot valve and diap hragm element)

In case of domesti c hot water (secondary side) pH lowe r than 7 -> the hardne ss of the water must be larger than th e sulphate element

at T idle nom. + 10 °C

Circulation water / glycolic water up to 30%

Domestic hot water (chlorine (cl) content max. 200 ppm)

1) ,2) ,3)

2 … 100

2 … 90

Dezincification resistant brass BS 2874

Ecobrass (CW724R)

Dezincification resistant brass BS 2874

Ecobrass (CW724R)

00 3L7120

–HCO

〉

––SO

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Data sheet Flow-compensated temperature controller AVTQ DN 15

Application principle

The controller AVTQ must be installed in the return pipeline only.

Design

1. Thermostatic actuator with

sensor stuffing box

2. Pressure spindle

3. Diaphragm housing

stuffing box

4. Nut

5. Diaphragm housing

6. Diaphragm spindle

7. Control diaphragm

8. Compression connection for

impulse tube

9. Intermediate ring

10. Nameplate

11. Main spring

12. Damping + teflon ring

13. Valve spindle

14. Valve ins ert

15. Pressure relief c ylinder

16. Valve body (main valve)

17. Handle for temperature setting

18. Spindle

19. Valve b ase

20. Spring retainer

21. Setting spring

22. Pressure equalizing hole

23. Valve cone

24. Valve body (pilot valve)

25. Compression connection for

impulse tube

26. Sealing bolt of sensor stuffing box

27. Gasket of sensor stuf fing box

28. Housing of sensor stuffing box

When domestic hot water (DHW) is tapped, flow through the pilot valve creates a pressure drop (force in the diaphragm housing) which is used to increase the temperature level from no-load (idle) to set tapping temperature.

This temperature increase causes the main valve to open for flow on the district heating side and close when the temperature level again falls to the no-load operating level. No-load operation prevents the district heating line becoming cold. Tapping temperature can be set individually.

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