Vaisala SDI5 Safe‑Drive System – Safety information and replacement instructions
This page provides important information about the safety issue identified in the SDI5 Safe‑Drive wash nozzle isolation valve used with the Vaisala Polaris PR53SD Safe‑Drive retractable process refractometer.
Background
There is a potential issue with the ball valve used in the wash nozzle isolation valve assembly of the SDI5. During retraction of the wash nozzle and specifically during the final phase of nozzle removal, process liquid may, under certain conditions, leak at process pressure through a seemingly closed isolation valve.
For safety reasons, the SDI5 valve must not be used for nozzle retraction under pressurized conditions, and specific precautionary measures remain in effect until a replacement has been installed.
Replacement assembly
Vaisala has developed a replacement wash nozzle isolation valve assembly to address the issue. The new assembly is based on the proven SDI2 platform and includes structural enhancements, including a reinforced blow‑off valve designed to safely relieve residual pressure. It also enables operators to visually confirm full nozzle retraction.
The replacement assembly is provided free of charge.
All mechanical and electrical interfaces remain the same. and the system functionality is not affected.
Required actions
To ensure safe operation, the SDI5 wash nozzle isolation valve must be replaced with the new assembly at the next suitable opportunity, such as a planned shutdown or another event when the process line is already depressurized.
1. Until the replacement is completed:
• Do not retract or remove the wash nozzle while the process is pressurized.
• Perform any maintenance involving the wash nozzle or isolation valve only when the process is depressurized.
2. After installing the replacement:
• Follow the updated instructions included with the new assembly.
• Dispose of the old SDI5 isolation valve locally in accordance with your site’s waste‑handling procedures; returning the component to Vaisala is not required.
Need support?
For questions, support with replacement planning, or help identifying affected installations, please contact [email protected]
Figure 1. SDI5 with the existing wash nozzle isolation valve highlighted
FAQ
Why is the valve being replaced?
Under certain conditions, process liquid may leak through the SDI5 isolation valve even when the handle indicates a closed position, especially during the final stage of nozzle removal if the process remains pressurized.
Is there a replacement available?
Yes. Vaisala has developed a new wash nozzle isolation valve assembly based on the SDI2 platform, including a reinforced blow‑off valve and improved structural components.
When is the replacement available?
The replacement wash nozzle isolation valve assembly is available for shipment now. Customers can request delivery through Vaisala Helpdesk with desired shipping date and address, and with the respective original Sales Order number(s). The new assembly will be supplied free of charge. Installation can be planned for the next suitable shutdown or scheduled maintenance window.
Is the replacement free of charge?
Yes. The replacement wash nozzle isolation valve assembly is provided free of charge. Installation‑related arrangements, such as planning a shutdown or other site‑specific work, are managed by the customer.
Is the replacement compatible with my existing system?
Yes. The replacement assembly is fully compatible with current SDI5 installations. Interfaces, connections, and overall system functionality remain unchanged.
Do I need to shut down the process to install the replacement?
Yes. The process line must be depressurized before removal or installation of the wash nozzle isolation valve.
Can I continue using the SDI5 valve until the replacement is installed?
You may continue using the system under the existing precautionary measures, but the SDI5 isolation valve must not be used for retraction under pressurized conditions. Follow all safety instructions until the replacement is installed.
What do I do with the old SDI5 assembly?
Dispose of it according to your site's waste‑handling procedures; returning it to Vaisala is not required.
