How do i change the upp and lower heating elements

lime is probably clogging the outlet water lines

I should like to hope I have your answer.
If yours is like most U.S. model, it is called a 220 volt unit.
That is not really 220 volts, it is really 2 separate 110 volt units.
What that means is, there are actually 2 separate 110 volt hot wires to the water heater, usually one hot wire is black, and the other hot wire is red.
One is for the upper heating unit, one is for the lower heating unit. Perhaps your lower unit has blown the circuit breaker for that line.
I mean the circuit breaker in the main fuse box/circuit breaker box.
Did you test the lower wiring to see if the hot wire is hot?
If it is hot, be sure to test the ground wire, and also the wiring between the bottom and the top of the heater inside it.
God bless your efforts.

When the top of the tank is hot the upper thermostat removes power from the upper heating element and transfers the power to the lower thermostat and heating element. If the lower thermostat is defective, then the lower portion of the tank will not be heated and the supply will be greatly reduced. You replaced both elements however check that the lower element is coming on after ther upper one cuts out and is acutally working.
Check for power at the upper thermostat terminals where the power is sent to the lower thermostat and heating element. If there is no power then the upper thermostat should be replaced. If there is power then check for power at the lower heating element. If there is no power at the lower heating element then replace the lower thermostat.
If there is power to the lower heating element then it should be getting hot. If it is not, maybe defective. Another possibility is a broken dip tube. Check for a broken dip tube and replace if necessary.

If the dip tube is broken, the incoming cold liquid can mix with the out going hot liquid and cause it to seem as though you are running out.

1) Residential water heaters are non-simultaneous. Only one element works at a time.
Upper element comes on until top of tank is heated, and then lower element is switched on until lower part of tank is heated. Lower element keeps tank hot during standby hours
http://waterheatertimer.org/How-it-works.html

2) Typical Whirlpool energy smart has 4500Watt elements. Look at label on side of tank
If both elements were ON, that would draw 9000Watts or 37.5 amps, requiring 50 amp breaker and 8 gauge wire. V x A = Watts.
All dual-element tanks are 240V.
Whirlpool energy smart requires 10 gauge wire and 30 amp breaker so electronics are not starved during operation. If your wire or breaker are undersized, that is suspect for repeated failure.
http://waterheatertimer.org/Whirlpool-Energy-Smart-electric.html

3) Typical electric water heater heats 21 gallons per hour. First hour delivery is higher since elements heat water as you use it. Overall however, electric water heater cannot re-heat as fast as gas because gas water heater burner carries more BTU punch per minute than electric element. Gas heats about 41 gallons per minute, with higher first hour delivery.

4) IF YOU HAVE OLDER energy smart and installed newer board, then you could have non-simultaneous operation is reversed so that lower element comes on first.
Read following post at Fixya:
http://www.fixya.com/support/t8263226-our_water_heater_doing
Contact Whirlpool 1-877-817-6750

5) Another potential problem is that you have sediment inside tank and that is reducing efficiency of lower element.
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html
http://waterheatertimer.org/How-to-test-water-heater-element.html

Add a comment with your experience so others with same-similar problem can benefit.

Also take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

I am guessing this is an ele water heater and the temp setting are not the problem.
Problem: Not enough hot water or water temperature too low. When the top of the tank is hot the upper thermostat removes power from the upper heating element and transfers the power to the lower thermostat and heating element. If the lower thermostat is defective, then the lower portion of the tank will not be heated and the supply will be greatly reduced.
Check for power at the upper thermostat terminals where the power is sent to the lower thermostat and heating element. If there is no power then the upper thermostat should be replaced. If there is power then check for power at the lower heating element. If there is no power at the lower heating element then replace the lower thermostat.
If there is power to the lower heating element then it should be getting hot. If it is not, replace it. Another possibility is a broken dip tube. Check for a broken dip tube and replace if necessary.

The dip tub is located under the fitting where the hot water comes out.

Most electric hot water heaters have two thermostats, one near the top of the tank and one near the bottom, and are covered by removable metal cover plates. The thermostats are pressed firmly against the bare metal wall of the hot water heaters tank.

The top thermostat usually has a high limit switch that will trip if the water gets too hot. When it trips it shuts off the electricity to both the upper and lower heating elements.

To reset the high limit switch there is usually a red button that you must press. When the upper limit switch trips it is often an indication that something else has gone wrong with the heater.

When the top of the tank is hot the upper thermostat removes power from the upper heating element and transfers the power to the lower thermostat and heating element. If the lower thermostat is defective, then the lower portion of the tank will not be heated and the supply will be greatly reduced.
Check for power at the upper thermostat terminals where the power is sent to the lower thermostat and heating element. If there is no power then the upper thermostat should be replaced. If there is power then check for power at the lower heating element. If there is no power at the lower heating element then replace the lower thermostat.
If there is power to the lower heating element then it should be getting hot. If it is not, replace it. Another possibility is a broken dip tube. Check for a broken dip tube and replace if necessary.

Hope this helps out

Hello. It is common for the lower heating element to fail and need to be replaced. This is often due to sediment build up in the bottom of the tank. J.

You probably have a bad heating element. Probably the upper element.

change the thermostat on both upper and lower elements, and the elements depending on the age of the water heater, if it is over 6 years old consider changing the water heater,

If the water does not heat, then you have to troubleshoot to find the problem. With a voltmeter determine if 240VAC is actually getting to the water heater. Take care here - a defective circuit breaker can give a false 240 volt reading - check for the 240 volts across the upper element (i.e. when the 240 volts has a live load on it, not just an open circuit test).
Also, remember, the upper element has priority over the lower element, and if the water is cold, the upper element will try to turn on and this locks out the lower element (only one element is allowed to heat at any given time). The lower element comes on ONLY after the upper thermostat is satisfied. Therefore if the upper heating element is burned out you will never get any hot water. If you suspect this, TURN OFF THE POWER TO THE HEATER and take a resistance check of the upper element.