Having Concerns with the Shutoff of your Pressure Regulator?

Are you Experiencing a Downstream Pressure Increase when your Pressure Regulator is Shut Off? Watch this video where we will address a customer’s concerns regarding the shut off of their Mark 60 Pressure regulator.

Video Transcript

Why downstream pressure might increase when a regulator is closed?

The Problem: A customer reported that when flow is shut off (e.g., after filling a truck with compressed gas), the downstream pressure eventually climbs to match the upstream pressure.
Normal Phenomenon: This is considered normal for a Class 4 regulator.
Leakage Standards:
- *Class 4: This allows for a leakage value of 0.01% of the maximum CV at a 50 PSI differential. Higher pressure differences will result in more visible leakage.
- Class 6: If your system requires no flow for long periods without pressure buildup, the video recommends products like the Mark 68, which offers Class 6 shutoff. Class 6 is much tighter, defined as only one bubble of air per minute.
Industry Standards: These shutoff standards are set by the Flow Controls Institute (FCI) under the standard ANSI/FCI 70-3.

What is Shut off in Pressure Regulator?

Shutoff in a pressure regulator refers to its ability to fully close and stop downstream flow once the desired outlet pressure is reached.

When the regulator achieves proper shutoff, it prevents pressure creep, leakage, and unwanted flow. However, many applications face under pressure shutoff or over pressure shut off concerns when the regulator cannot seal tightly.

The close off pressure standards like hard (ANSI Class IV) or soft (ANSI Class VI bubble tight) shutoff determines how well the regulator can achieve a complete seal under real operating conditions.

If the valve shutoff pressure is not appropriate for the system, the regulator may struggle with stable under pressure shut off, leading to performance issues.

Understanding these shutoff behaviors helps ensure consistent operation and safer system pressure control.