Troubleshooting odd situation

[strizek88]

Hoping someone can help troubleshoot an odd situation that I haven't been able to answer via many Google searches!

The hot water in our primary kitchen sink has begun working inconsistently. It may provide hot water immediately and then get cold and take many many minutes to get hot again. Or even after a few minutes it won't get hot. It just varies. Our kitchen prep sink, and all other taps in the house, are fine.

We have a tankless heater, if that matters, and the pressure in this sink is about 25% less than other kitchen sink. I believe it's always been this way, but may have recently become a bit worse along with the hot water issue. Just wanted to mention.

My husband thought it might just need a new cartridge, but that did not affect anything.

Any help is most appreciated!

 

[johnjh2o]

If the water flow is low it may not be allowing the tankless heater to fire. Try removing the aerator on the faucet and clean it.

 

[frodo]

If the aerator is clean then..
Sounds like you need a new cartridge, If ALL other fixtures are getting adequate hot water
and the only problem is at the sink.

 

[Diehard]

It sounds like they already tried a new cartridge, "but that did not affect anything."

 

[frodo]

was the aerator cleaned?

 

[strizek88]

Aerator was not cleaned, so we'll try that! And yes, ALL other taps in the house are working perfectly fine.

 

[Jeff Handy]

There can be a tight spot from sediment in one or two other places in that kitchen faucet.

There is likely a little check valve that can get easily clogged with minerals, and also a tiny plastic and rubber gizmo that chokes down the water flow to the very low current govt standards.

Cover the drains with a wet towel, before you start taking any little parts apart!

 

[strizek88]

Thanks to those who replied. My husband cleaned out the aerator and said is was totally gummed up with literal black sand. We're back in business!