Danfoss AFA 2 Pressure Relief Controllers User Guide

: June 4, 2024
: Danfoss

Danfoss AFA 2 Pressure Relief Controllers User Guide

AFA 2 / VFG 2(1) DN 15-250, VFG 22(1) DN 65-250

Safety Notes

Prior to assembly and commissioning to avoid injury of persons and damages of the devices, it is absolutely necessary to carefully read and observe these instructions.
Necessary assembly, start-up, and maintenance work must be performed only by qualified, trained and authorized personnel.
Prior to assembly and maintenance work on the controller, the system must be:

depressurized,
cooled down,
emptied and
cleaned.

Please comply with the instructions of the system manufacturer or system operator. Definition of Application

The controller is used for pressure relief of water and water glycol mixtures for heating, district heating and cooling systems.

The technical data on the label plates determine the use.

Scope of Delivery ❶

*) adapter 003G1780, accessory sold separately,
**) Impulse tube AF, accessory sold separately

Assembly

Admissible Installation Positions ❷

① media temperatures up to 150 °C: Can be installed in any position.
② media temperatures > 150 °C. Installation permitted only in horizontal pipelines with the actuator oriented downwards.

Installation Location and Installation Scheme ❸

Valve Installation ❹

Install strainer ① before the
Rinse system prior to installing the
Observe flow direction ② on valve
Install
Tighten screws crosswise in 3 steps up to the torque.

Actuator Installation ❺

Remove the spindle protection cup and release the valve spindle by removing the nut, washer and cardboard
Align the actuator stem with the valve stem, connect both stems and turn gently the whole pressure actuator clockwise with both hands, until the stems are fully connected (valve stem fully screwed into the actuator stem).
Release spring (unstress) and release the uninon nut by pulling out the blocking
Tight the union nut by hand or with wrench key using minimal force
Release the pressure actuator by turning it counter clockwise for approximately half a
Observe the position of impulse tubes connection to the valve and align the actuator
Hold the actuator in the position and tight the union nut to the valve with 100- 120 Nm

Impulse Tube mounting ❻

Which impulse tubes to use?

The impulse tube set AF (2×) ❻① can be used: Order No.: 003G1391

or use the following pipes:

Steel / Stainless steel	Ø 10×1	ISO 1127 D3/T3
Copper	Ø 10×1	Cu-DHP R200 EN12449

•The impulse tube ③ can be connected directly to the valve ④ or to the

pipeline ⑤.

⑥ ventilation socket, do not connect impulse tube.

Connection to the valve ❼

Remove plug ① at the
Screw in threaded joint G 1/4 ② with copper seal, Torque 40

– or –

Connection to the Pipeline ❽①

No connection downwards/upwards ②, could bring dirt/air into an impulse tube.

Cut pipe in rectangular sections ③ and
For copper pipe:

insert sockets ④ on both sides.

Verify the correct position of the cutting ring ⑤.
Press impulse tube ⑥ into the threaded joint up to its
Tighten union nut ⑦ Torque 40

Insulation ❾

For media temperatures up to 120 °C the pressure actuator may be insulated ①.

Dismounting ❿

**Prior to dismounting depressurize system or use shut off valves on the

impulse tubes!** ①

Carry out dismounting in following steps: ②

Fasten pressure actuator with the safety bands to the fixed points in surroundings
Before releasing the actuator, fully release the union nut
Hold the pressure actuator with both hands, and release it by turning it counter clockwise ~30 During turning, control the actuator weight all the time to prevent unexpected fall of detached actuator.
Carefully remove the actuator from the

Before installing actuator back to the valve, setting spring must be fully released again.

Leak and Pressure Test ⓫

The pressure behind the valve ② must not exceed the pressure before the valve ①.

Observe nominal pressure ⑤ of the valve.

Caution:

The valve is closed without pressure and it opens on rising pressure before the valve.
Prior to pressure tests , it is absolutely necessary to remove the impulse tube at the valve ④.
Close connections with plugs G ¼ ISO 228.
Max. pressure [bar] with connected impulse tube:

AFA 2 cm2	32	80	160	320	640
bar	16	5	2.5	1.3	0.35

Max. test pressure with disconnected impulse tube must not exceed the plant testing pressure and must always be lower than 1.5 × PN.

Non-compliance may cause damages at the controller ③.

Filling the System, Start-up ⓬

Non-compliance may cause damages at the controller ③.

Open shut-off devices that are possibly available at the impulse tubes ④.
Slowly open valves in the
Slowly open shut-off device ⑤.
Slowly open shut-off device ⑥.

Putting out of Operation

Slowly close shut-off device ⑤.
Slowly close shut-off device ⑥.

Setpoint Adjustment ⓭

Set-point range see rating plate ①
Start-up of system, see section ⓬.
Start pump ②
Observe pressure indicator ③
Slightly close fitting ④ behind the pump (in flow direction) so that the pressure ③ is
Adjustment of the pressure in front of the valve
- Turning to the right ⑥ reduces the set-point (unstressing the spring – tension spring)
- Turning to the left ⑦ increases the set-point (stressing the spring)
If the required pressure ③ cannot be set, further close the fitting ④.
The set-point adjuster ⑧ may be
Release the not yet used pointer ⑨, move it to the set position and fix it with the screw to mark setting position