Water pressure low and not hot even after fixing broken heating element. Need advice.

[Surfer949]

A few days ago I noticed the water pressure in the kitchen sink was very low with almost no hot water. Then the same issue started with my shower head. I opened the unit and one of the heating element was cracked. I replaced it with a brand new one and cleaned the other one. After servicing the unit, the first shower was fine but then the issues appeared again. I'm baffled and frustrated at this point and I'm not sure if I need to call a plumber or Ecosmart support. Anyone experienced these similar issues?
System: Ecosmart 18 tankless water heaterhttp://www.ecosmartus.com/products/electric-tankless/eco-18/#product-tab2

History: unit was functioning perfectly until a week ago. It came with the house build in 2013. The only major change in plumbing was done 3 weeks ago for a sprinkler system install. However there were no hot water or water pressure issue until just a few days ago. House location is in Houston,TX

Symptoms:
Very low water pressure in kitchen sink with warm water only, same with shower head. I did notice when kitchen faucet is on hot, the tankless digital display unit doesn't turn on (which does for other hot faucet in house).
Bathtub water pressure is ok with warm water for 10 seconds but will start "chocking" at full blast
Bathroom sinks hot water pressure is good with hot water.

DIY service: Replaced cracked heating element, the other one cleaned it with vinegar. Also cleaned the flow sensor as it was not displaying temperature.

With the low pressure in kitchen, would it be wise to not use the dishwasher?

 

[Surfer949]

Just did another test in secondary bathroom. Water is hot for 1 minute then goes warm for bath sink and bathtub. Pressure is good and strong. Meanwhile kitchen sink is has low pressure.

 

[Sponsor]

 

[Reach4]

I would look for debris in the kitchen aerator. Maybe debris went from the water heater to the aerator and other places.

 

[Surfer949]

I would look for debris in the kitchen aerator. Maybe debris went from the water heater to the aerator and other places.

The cracked element was in bad shape and probably had a lot of residue. Going to clean out the head of the kitchen sink and shower and replace the 2nd element tomorrow, it may also be bad even though it's not cracked.

Silly question but how do you correctly clean a aerator?

 

[Reach4]

how do you correctly clean a aerator?

Depends on the faucet. On a conventional faucet, you unscrew the aerator housing. Look inside, being careful to not lose parts. Old ones had screens. Newer may have a little cartridge, but there will be a part that serves as a stream. While the aerator is off, run the water to let higher flows blow out any remaining pieces.

If you don't have a faucet that has an aerator on the spout, post a picture of what you have, or name brand and model. Somebody will probably know.

 

[Surfer949]

Cleaned aerator twice and looks like sediments from cracked heating element keeps blocking the mesh filter. May leave faucet without head until all sediment is flushed out