Danfoss EVRA 32, EVRA 40 Service guide

Fitters notes Solenoid valves

Contents Page

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

EVRA 32 & 40 precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

When pressure testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

The coil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

The correct product. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Solenoid valves

© Danfoss A/S (AC-DSL/MWA), 10 - 2006 DKRCC.PF.000.G1.02 / 520H1459 13

Notes

14 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Solenoid valves

Installation

All EVR/EVRA, and EVH types solenoid valves
operate only when installed correctly in the
direction of ow, i.e. in the direction indicated by
the arrow.

Normally, solenoid valves installed ahead of a
thermostatic expansion valve must be close to
that valve.

This avoids liquid hammer when the solenoid
valve opens.

Ensure that pipes around the valve are properly
installed so that no fracture can occur.

Solenoid valves

Af0_0001

Af0_0003

EVRA 32 & 40 precautions

Brazing/welding EVR/EVRA and EVH solenoid
valves does not normally necessitate dismantling,
provided steps are taken to avoid heating the
valve.

Always protect the armature tube against

Note!

weld spatter.

After tacking the valve to the pipe, remove the
valve body to protect O-rings and gaskets against
heat. In installations with welded steel pipe, a
FA type strainer or similar mounted ahead of the
solenoid valve is recommended. (On new plant,
ushing out before starting up is recommended).

Af0_0004

© Danfoss A/S (AC-DSL/MWA), 10 - 2006 DKRCC.PF.000.G1.02 / 520H1459 15

Fitters notes Solenoid valves

When pressure testing

All solenoid valves in the system must be open,
either by applying voltage to the coils or by
opening the valves manually (provided a manual
operation spindle is tted).

Remember to screw the spindle back before
starting up, otherwise the valve will be unable to
close.

Af0_0005

Always use counter force when nally
tightening the solenoid valve on pipes, i.e.
two spanners on the same side of the valve.

Af0_0006

16 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006

Fitters notes Solenoid valves

The coil

When tting the coil, it has merely to be pressed
down over the armature tube until a click is
heard. This means that the coil has been correctly
tted.

Note: Remember to t an O-ring between valve
body and coil.

Be sure that the O-ring is smooth, not damaged
and that the surface is free from paint or any
other material.

Note: The O-ring must be changed at service.

The coil can be removed by inserting a
screwdriver between valve body and coil. The
screwdriver can then be used as a lever to loosen
the coil.

Solenoid valves

Af0_0018

Af0_0019

Be careful with cable entries. It must not be
possible for water to enter the terminal box. The
cable must be led out via a drip loop.

The entire cable circumference must be retai­ned by the cable entry.

Therefore, always use round cable (which is the
only type of cable that can be sealed eectively).

Be aware of the colour of leads in the cable.
Yellow/green is always earth.
Leads of one colour are either phase or neutral.

Af0_0009

Af0_0010

Af0_0011

© Danfoss A/S (AC-DSL/MWA), 10 - 2006 DKRCC.PF.000.G1.02 / 520H1459 17

Fitters notes Solenoid valves

The coil (cont.)

The correct product

(The “old” coil type)

When removing a coil it might be necessary to
use hand tools, e.g. two screwdrivers.

Make sure that coil data (voltage and frequency)
and supply voltage correspond. If they do not,
the coil might burn out. Always ensure that valve
and coil match each other.

When replacing a coil in an EVR 20 NC
(NC = normally closed) note:

- A valve body using an a.c. coil has a square
armature.

- A valve body using a d.c. coil has a round
armature.

Fitting the wrong coil results in a lower MOPD.
See data on the top nut. As far as possible, always
choose single-frequency coils. These give o
less heat than double-frequency coils.
Use NC (normally closed) solenoid valves for
systems in which the valve must remain closed
(de-energised) for most of the operating time.
Use NO (normally open) solenoid valves for
systems in which the valve must remain open
(de-energised) for most of the operating time.
Never replace an NO (normally open) solenoid
valve with an NC (normally closed) valve - or vice
versa.

Af0_0012

Af0_0013

Af0_0014

(The new “clip-on” coil type)

Two labels are supplied with each clip-on coil
(see illustration).

The adhesive label is for attaching to the side of
the coil, while the other, perforated label should
be placed over the armature tube before the coil
is clicked into position.

Af0_0015

Af0_0020

18 DKRCC.PF.000.G1.02 / 520H1459 © Danfoss A/S (AC-DSL/MWA), 10 - 2006