Trouble Shooting; Fault, Possible Cause, Remedy; Diaphragm Break Of The Controller Sava - Danfoss PCVA Instructions Manual

Instructions
8

Trouble Shooting

12 | © Danfoss | 2016.06
PCVA, PCVSAA

8.1 Fault, Possible Cause, Remedy

Fault Possible cause
Air in the actuators
Controller does not
hold the pressure on a
constant levell
Impulse tubes or impulse tube connections are
dirty or damaged.
Pilot valve AVA (SAVA) does not close:
Valve seat or plug is dirty or damaged.
Pressure is too high
Valve VFG21 does not close:
Valve seat or plug is dirty or damaged.
Rolling diaphragm in the actuator AVA (pilot
controller) is defective, i.e. valve AVA does not
close.
Rolling diaphragm in the actuator SAVA (pilot
controller) is defective, i.e. valve AVA is not closed
by the safety diaphragm. In this case, some water
Pressure is too low, penetrates at the threaded fitting of the actuator.
no or low flow
Rolling diaphragm in the actuator of the valve
unit is defective, i.e. valve VFG21 does not open.
The trim can be replaced by qualified personnel up to DN 125.
1)
From DN 150 replacement should be carried out by the Danfoss service personnel.

8.2 Diaphragm Break of the Controller SAVA

If the control diaphragm 1 breaks, pressure is
developped in the two intermediate chambers 2.
This pressure acts upon the safety diaphragm 3
and causes the following:
- The valve is closed.
- The control function does not operate.
- A slight water leakage at the threaded joint 4
indicates a break of the diaphragm.
The controller must be replaced
Remedy
1. Loosen impulse tube connections at the
actuators by approx. 1 rotation.
2. Deaerate, Caution hot water !
(move impulse tube until medium
penetrates).
3. Tighten impulse tube connections.
1. Remove impulse tube.
2. Clean impulse tubes and impulse tube
connections and check for free passage.
1. Remove impulse tube.
2. Dismount actutor and trim.
Procedure see section 9.4.
3. Clean seat and plug.
4. If damaged, replace trim or valve.
1. Remove impulse tube.
2. Dismount actutor and trim
Procedure, see section 9.2.
3. Clean seat and plug.
4. If damaged, replace trim or valve.
1. Remove impulse tube.
2. Replace actuator, see section 9.3.
1. Remove impulse tube.
2. Replace actuator, see section 9.3.
1. Remove impulse tube.
2. Loosen union nut SW 46 and remove
actuator, see also section 9.1.
3. Replace actuator.
4
1) .
3
2
1
VI.JA.D2.5B