Danfoss SVA-S, SVA-L, SVA-ST, SVA-LT, SVA-HS Installation guide

Installation guide

Packing gland replacement SVA-S/L, SVA-ST/LT, SVA-HS – size DN 200

General All personnel working on valves must be

148R 9 628

Packing gland As a general rule, the packing gland must not be

Back-seating To back-seat the valve, turn the spindle counter-

qualied to work on refrigeration systems and be completely familiar with the system they are about to service. Any person intending to service a valve should carefully read this Standard Operational Procedure and the description of the particular valve and its operation before any work begins. If there are any questions, contact Danfoss before proceeding with the work.

removed if there is internal pressure in the valve. However, if the following precautionary measures are taken, the packing gland can be removed with the valve still under pressure, provided that the valve is safely back-seated.

clockwise until the valve is fully open. Use a 25 mm wrench.

Tighten the spindle counter-clockwise with 50 Nm ± 5 Nm (36.88 ft-lb ± 3.69 ft-lb) of force.

148R 9 628

Pressure equalization Important!

A small amount of refrigerant may still have accumulated behind the packing gland; it is extremely important that the service personnel are using appropriate protection equipment suitable for the actual refrigerant. In some cases, pressure forms behind the packing gland. Therefore, it is important to mount a handwheel (or a similar device). It should be fastened on top of the spindle while the pressure is equalized in order to ensure that the packing gland can be safely removed. The pressure can be equalized by slowly unscrewing the gland.

Do not remove the packing gland if the valve is not completely back-seated (not sealed tight – see specications above). If it is not possible to properly back-seat the valve (meaning potentially trapped refrigerant pressure behind the packing gland is not completely relieved within a few seconds when the packing gland is unscrewed), retighten the packing gland. Contact Danfoss (it may be necessary to pump out (evacuate) the system before proceeding with the removal of the packing gland). If pump-out is required, it is very important to ensure that the internal pressure is reduced to atmospheric pressure or below before the packing gland is unscrewed.

Packing gland replacement – SVA-S/L, SVA-ST/LT, SVA-HS – size DN 200

Inspect the internal surface If two grooves can be seen on the surface, go to

Step 1 Measure the distance from the top side of the

step 1.

If no groove is seen on the surface, go to step 2.

bushing to the top side of the bonnet. The dimension should be between 50 mm and 52 mm (1.97 in. to 2.05 in.). Be sure not to put the top side of the calipers into the groove of the bushing, use a ashlight for assistance. If the measurement is within the specied range, please proceed to step 3.

If this measurement is not within the specied range of 50 mm – 52 mm (1.97 in. – 2.05 in.), reinstall the existing packing gland into the bonnet and contact your local Danfoss Representative for further details.

Step 2 Use the tools provided (number 9 in repair kit

148B6473) to remove the washer.

Be sure not to scratch the spindle while removing the washer with the wire tools.

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