How to fix undersink filter faucet taking a long time to pressurise?

[jonathanchow]

Hi I recently replaced an undersink filter cartridge and faucet which was working great the first day, but now when I turn it on it takes about 30 seconds before it turns on properly. It slowly starts dripping and gradually builds up to normal water pressure. I'm guessing it's the tap not the cartridge but not sure why. There are no leaks and it does technically work, just not as it's meant to. It's this tap and this cartridge, not the same brand but they fit. It seems like the water pressure is taking time to build up and it just seems a bit off. Any assistance would be much appreciated. 

[EricL]

Hello @jonathanchow 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your filter faucet.

A possible cause for the slow flow is air trapped in the filter housing, which can restrict flow. If the filter wasn’t flushed properly during installation or replacement, or if there’s a slight leak in the fittings, air can enter and reduce water pressure. You may hear gurgling or bubbling sounds if this is the case. In some setups, a manual flush or bleeding procedure is necessary to remove trapped air.

Water pressure from the mains could also be lower than normal. If your home is experiencing reduced inlet pressure due to plumbing restrictions, a partially closed isolation valve, or municipal supply fluctuations then the filter and tap performance will be directly affected. It’s also worth checking that any pre-filters or sediment filters upstream of the AP8112 unit are clean and not obstructing flow.

Lastly, installation errors or a kinked hose in the water line can choke the water supply. Visually inspect the tubing for sharp bends or crushed areas, particularly where the line runs behind cabinetry or under the sink.

In most cases, replacing the filter cartridge with a new AP8112 unit and ensuring a proper flush after installation resolves the issue. If the problem continues even with a fresh cartridge, then airlocks or plumbing flow restrictions should be investigated more closely.

If you need further assistance, please let us know.

Eric