As a retired plumber with over 30 years of hands-on experience, I’ve tackled every toilet clog imaginable. But pressure assist toilets can present some unique challenges when it comes to unclogging compared to standard gravity flush toilets. In this guide, I’ll share everything I’ve learned over the years about how to unclog a pressure assist toilet quickly and effectively.
How Do Pressure Assist Toilets Work?
Before we dive into unclogging, it helps to understand what makes pressure assist toilets different. These high-powered toilets use compressed air instead of gravity to generate a strong siphon during flushing.
Here’s a quick rundown:
- Inside the tank is an air bladder or cartridge that gets filled with air. This allows only a small amount of water to remain in the tank.
- When you flush, the valve opens and the compressed air in the bladder presses down into the bowl. This forced air is what creates the strong siphon action and suction to clear the bowl in one flush.
- The air pressure is around 45 psi, compared to just 2-3 psi for a gravity toilet.
- Less water is required per flush, making pressure assist toilets very water efficient.
So in essence, these toilets rely on forced air pressure instead of gravity to clear the bowl. This makes them more effective at flushing away waste with just one flush. But it can also cause some unique clogging issues.
Why Do Pressure Assist Toilets Clog?
While all toilets can get clogged, there are a few reasons why clogs seem to happen more easily in pressure assist models:
- Lower water levels – The bowl uses less water per flush, so any debris or waste left behind has less water to float it down the drain.
- Powerful flush – The intense suction can pull waste too far up into the trap or drain pipe, causing a partial or complete clog.
- Air intake issues – If the air bladder doesn’t fully pressurize with air, flushing power is reduced, leading to clogs.
- Ventilation problems – Lack of proper ventilation behind the toilet can allow condensation buildup, affecting flushing power.
- Old rubber fittings – Over time, the rubber gaskets and fittings inside the tank can warp or degrade, causing poor flushing and clogs.
So in summary, the very mechanisms that allow pressure assist toilets to work can also contribute to clogging in some cases.
How to Unclog a Pressure Assist Toilet
If you’re dealing with a clogged pressure assist toilet, there are a few methods I’d recommend trying before calling a plumber:
Use a Plunger
This is the first thing to try if you have a simple toilet clog. Place a plunger over the drain hole forming a tight seal. Work the plunger up and down rapidly 10-15 times to try and dislodge the clog. Flush again to see if the clog clears. You may need to repeat this process a few times. Make sure you have a plunger designed for toilets rather than sinks – it needs to form a tight seal on the drain hole.
Check for Tank Debris
Debris around the air bladder or water intake screen can impede flushing power. Turn off the water supply behind the toilet. Flush to empty the tank. Then use a flashlight to look for any debris around the air bladder, intake screen, or other internal components. Use tongs to remove any debris. Make sure the intake screen is not clogged.
Remove the Tank Lid
With the tank empty, remove the tank lid and set it aside. Check the condition of the flush valve seal and other rubber gaskets. Make sure they are clean and seated properly. Any warped or degraded rubber can reduce flushing power. Replace any faulty gaskets.
Check the Water Supply Line
Make sure the supply valve behind the toilet is fully open. Check the supply line for any kinks or clogs that could block water flow. Disconnect the line and inspect the water intake screen. Clean out any grit or debris clogging the screen.
Clear the P-Trap
The P-trap is the curved pipe below the toilet. Place a bucket beneath to catch water. Unscrew the nuts on the underside of the toilet. Remove the pipe and inspect it. Use a wire coat hanger to fish out any debris clogging the trap. Reinstall the P-trap.
Use a Closet Auger
For stubborn clogs deeper in the drain line, a closet auger is your next resort. Feed the flexible 3-6 foot auger down the toilet drain. Crank the handle clockwise while gently pushing the auger head down. When you feel resistance, that’s the clog – work the auger to break it up. Retract the auger and flush again.
Check the Vent Stack
Inadequate ventilation behind the toilet can reduce flushing power. Make sure the vent stack leading up from the drain line is clear of any blockages. Also check that the roof vent cap is not obstructed by debris or nests. Proper air flow is needed for the pressure assist mechanism.
Call a Professional Plumber
If you’ve tried all these methods and the clog still persists, it’s time to call a professional. A plumber has high-powered tools like hydrojets that can target clogs deep in the drain line. They can also snake the main sewer line if needed. A plumber can determine if issues like a faulty fill valve, air bladder, or flush valve seal are reducing flushing power and causing chronic clogs.
Preventing Future Clogs
To help avoid clogs down the road, here are my top tips:
- Only flush toilet paper – no wipes or other items that can snag in the pipes.
- Install a toilet tank water filter to stop debris from entering the tank.
- Use a silicone-based lubricant on the flush valve seal and other internal gaskets every 2 years.
- Keep the water intake screen clear of sediment and debris.
- Use a drain cleaner/enzyme product monthly to break down waste and keep drains clear.
- Check proper ventilation behind the toilet.
- Have a plumber inspect fittings and seals every 3-5 years or if flushing issues arise.
When to Call a Plumber for Pressure Assist Toilet Clogs
As a general rule, I recommend calling a professional plumber if:
- You’ve tried all the DIY methods with no success.
- The clog is very deep in the drain line.
- You have chronic clogging issues.
- The toilet needs extensive disassembly to access the clog.
- There are issues with the water supply valve, tank components, or ventilation.
- You want to prevent damage from improper repairs.
While some basic clogs can be DIY, there are times when a pro is needed. They have the expertise and tools to fully diagnose and fix ongoing issues.
Key Takeaways on Unclogging Pressure Assist Toilets
After years on the job, here are my most important tips to remember:
- Try a plunger first, sealing it tight over the drain and plunging vigorously.
- Check the tank for debris clogging the intake screen or air bladder.
- Inspect and replace any warped rubber gaskets affecting flush power.
- Make sure the water supply valve is fully open.
- Clean out the P-trap under the toilet.
- Use a closet auger for clogs further down the pipes.
- Check proper ventilation behind the toilet.
- Call a plumber for deep, chronic, or complex clogs.
- Prevent clogs by only flushing toilet paper and using drain cleaner monthly.
I hope these tips from my years of experience make it easier to get your pressure assist toilet flushing like new again. Let me know if you have any other questions – I’m always happy to share more of what I’ve learned after decades as a plumber!
