the pressure gauge on my presto canner is reading way higher than the regulator weight should allow, like 20 psi when i'm using the 15 lb weight, is it broken?

Diagnosis

The Presto 01755 utilizes a dual-system approach to pressure management: a physical weighted regulator (the "jiggler") and a visual pressure gauge. The weighted regulator is the primary safety and control mechanism. Because it relies on gravity and a specific mass (15 lbs), it physically cannot allow the internal pressure to exceed its rated limit unless the vent pipe is obstructed. If your 15 lb weight is dancing or venting steam, but the gauge reads 20 PSI, the gauge is out of calibration or has a mechanical failure. This discrepancy typically occurs due to "gauge drift," where the internal Bourdon tube (the curved metal tube that expands under pressure) loses its elasticity or becomes skewed. It can also happen if the gauge was dropped or exposed to extreme temperature fluctuations during storage. To confirm the gauge is the culprit, observe the regulator weight; if the weight is actively venting steam while the gauge reads 20 PSI, the pressure inside is actually 11-15 PSI, and the gauge is simply lying to you. If the weight is sitting perfectly still and silent while the gauge reads 20 PSI, you have a dangerous over-pressure situation caused by a clogged vent pipe.

How to Fix It

Since the gauge is an accessory and not the primary pressure control, the fix involves verifying the vent path and replacing the faulty component. Follow these steps precisely:

1. Allow the canner to cool completely and ensure the pressure has dropped to zero. Remove the lid and set it on a flat surface.
2. Unscrew the pressure gauge by rotating it counter-clockwise. Inspect the threaded port where the gauge seats.
3. Using a thin pipe cleaner or a small 1/16" drill bit (by hand, not powered), gently clear any debris, mineral deposits, or food particles from the small orifice leading from the pot interior to the gauge mounting point.
4. Inspect the rubber gasket or seal on the gauge thread. If it is cracked or pinched, the gauge may be reading erratic pressure due to air leaks.
5. Since the Presto 01755 gauge is not field-calibratable, you must replace it if it continues to read 5+ PSI above the regulator weight. Purchase a genuine Presto replacement gauge (Part #01755-G) to ensure the threading and seating match the aluminum lid perfectly.
6. Install the new gauge, ensuring it is snug but not over-tightened, as over-torquing can warp the aluminum threads of the lid.

If That Didn't Work

• Check the Vent Pipe for Obstructions. If the regulator weight is NOT venting but the gauge reads 20 PSI, the vent pipe is clogged. Remove the regulator weight and use a paperclip or a thin wire to poke through the vent pipe to clear any trapped food particles or mineral buildup. This is a critical safety step.
• Verify the Weight Mass. Ensure you are using the genuine Presto 15 lb weight. If you are using a generic or third-party weight that is heavier than the factory specification, it will actually allow the pressure to rise higher than 11-15 PSI, which would make the gauge reading accurate and the weight the problem.
• Inspect the Lid Seal. A leaking lid gasket can sometimes cause turbulent airflow near the gauge port, leading to erratic readings. If the lid is leaking steam from the sides, replace the gasket before trusting the gauge.
• Test with a Different Heat Source. If you are using a high-BTU outdoor burner, the rapid heat-up can cause "pressure spikes" that the gauge picks up but the weight compensates for slowly. Lower the heat to a steady simmer once the weight begins to dance.

Heads Up

• Always trust the weighted regulator over the gauge. The weight is a physical constant; the gauge is an electronic or mechanical estimate.
• Never attempt to "calibrate" the gauge by opening the casing; this destroys the seal and renders the tool useless for food safety.
• Clean the vent pipe with a wire every 5-10 uses to prevent pressure buildup that could trigger the emergency safety plug.
• Avoid using the canner if the gauge is missing or broken if you are processing low-acid foods, as the gauge provides the necessary confirmation that the pot has reached the required temperature for botulism prevention.