The timer is used on an Electric Point of Use 2.5 water heater. Currently I get hot water only about two hours in the evening. Before it was --on demand. I opened the timer box and one of the timer box" screw-on pointers " I don't koow the real name for this thing but it indicates where the time is set. Do I need a new timer or have this "thing' put back on. I need guidance because I am a widow and would be subject to a plumber overcharging me.

The unit doesn't like to drain without air coming in on top of water, so flushing with pressure applied is the preferred way. Be careful, see if you have power coming into unit. Turn off power and open the connection connection plate I would suspect that if the breaker is supplying power, sometime I have found that the connections are not properly made.. . If you a timer to limit operational hours take it out and go directly to romex from breaker panel.I f water starts hot and then go cool very quickly the bottom heating element and or thermostat is not working. Remove lower element cover and with power off check element resistance you can compare upper and lower element readings. From experience I never repair water heaters: time and material is more than new unit. You will need to buy element socket heating element(s) and or thermostat(s). In the end you still and old water heater.

1) Test elements, and if elements check out, then replace both thermostats.
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html#new
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html#warranty

2) Add a comment with result.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

large water heater, turn p the themo stat to a higher setting ( watch for burns with young childern and older folks)

or the best install a tempering valve. this valve mixs hot water with cold water before it goes into the building.

Again if you have young ones or old people they can burn faster than any other group.the best is a larger heater for the DIY person.

Thanks Tom

I don't understand everything being asked, so add a comment any time.

Problem1 is excessive electric bill.
Suspect is new 120Volt Taco recirculation pump.
Look at motor nameplate for amps and watts and HP. Taco pump is usually robust 1/3 HP which is 252 watts or same as running four 60 watt light bulbs.
If pump runs 18 hours per day x 252 watts = 4536 watts or 4.5 Kilowatts per day
Buy a kill-o-watt meter that plugs into outlet, and plug Taco pump into the meter for 48 hours.
This will give you total watts used for that time period.
1000 watts = 1 kilowatt.
Electric bill is probably 12 to 20 cents per kilowatt.
So if Taco uses 4.5 kilowatts per day, that is $.54 to $.90 per day multiplied by 30 days.
So cost is $15 to $30 per month.

Problem2 is Taco runs too long.
Taco operates either by thermostat or by timer. You choose which mode by using slide switch that is usually located under the timer dial. Set switch to TIMER to use timer, and ON to use thermostat, and off to turn TACO off.
If Taco is set for thermostatic operation, the Taco might be defective. Or there could be crossover problem at single handled faucet.
Another problem could be air in the water line: install air vent.
http://waterheatertimer.org/Crossover.html
http://waterheatertimer.org/Water-heater-recirculation-system.html
http://waterheatertimer.org/How-to-set-timers.html

Electric water heater typically makes 21 gallons hot water per hour.
Gas heater makes 41 gallons per hour.
If you use a timer on electric heater, it will make enough hot water for shower in about 15 minutes summertimer and 30 minutes wintertime. So incoming water temperature is a factor.

If your water heater is not full of water before turning on electricity, then elements will burn out.
Also the ECO might be tripped out: open top cover and push in red reset button.
How to troubleshoot electric water heater:
http://waterheatertimer.org/How-to-troubleshoot-electric-water-heater.html

You are not supposed to move the time arrow.
http://waterheatertimer.org/Paragon-timers-and-manuals.html

4000 series time arrow is pointed at 8:00.

To set current time, lift and rotate dial clockwise until current time lines up with pointer.
Put X2772 trippers on dial at times you want water heater to turn on.
Minimum on-off with Paragon 4000 is 1-1/2 hours because trippers are so fat.
You can replace 4000 timer with electronic timer and control exact on-off down to the minute:
http://waterheatertimer.org/Boxtype.html

Electric water heater heats about 21 gallons of water per hour.
Shower uses 6-9 gallons hot water.
Bath uses 10-12 gallons hot water.
Average water heater that is not connected to timer, runs about 3 hours a day. You can make timer pay off by keeping time schedule lower than 3 hours.

Following link shows how to figure cost for electric water heater:
http://waterheatertimer.org/Figure-Volts-Amps-Watts-for-water-heater.html

Following link shows several ways to save with water heater, plus general information to save money long-term:
http://waterheatertimer.org/9-ways-to-save-with-water-heater.html

Paragon 8145-20 is a 240V defrost timer
It is probably not best choice for water heater timer
Timer initiates defrost cycles each 4 hours.

A water heater timer should have more scheduling options.
-For example estimates show average run-time for water heater is 3 hours per day, depending on incoming water temperature, thermostat setting, and number of gallons used.
-To save money using water heater timer, you have to schedule times carefully so water heater runs less than 3 hours per day.
-Now your average electric water heater heats about 20 gallons per hour.
-Average shower uses 4-9 gallons hot water, so water heater needs to run 15-30 minutes (15 summer, 30 winter)
-Average bath uses 12-15 gallons hot water so water heater runs 45-60 minutes
-But lets say you run water heater for 1 hour and make 20 gallons of hot water. Then you take a shower, expecting hot water to remain in tank.
-Here's the problem ... cold water entered the tank to replace the shower water ... and the new cold water is cooling the rest of the tank.
-So a timer means scheduling hot water to match shower and bath events. For example taking shower and bath in immediate succession.
-Or set the timer for each individual hot water event ... for example set timer for 1/2 hour for shower, and later timer turns on 1 hour for bath, or 1-1/2 hr for 2 baths, etc
-> The flexible programming described above is not a characteristic of defrost timers.
I suggest Intermatic WH-31 240V or Intermatic T-104 240V or GE 15207. These are mechanical repeat-24 hour timers with manual override where each day has same schedule.
Digital programmable timers like Intermatic EH40 offer 7-day, 40 event programming. Weekends and weekdays can be different.
To see several box-type timers:
http://waterheatertimer.org/Boxtype.html

Do you have the auto-circ recirculation pump with timer?
If so, here is manual for that specific product:
Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

http://waterheatertimer.org/Auto-circ-manual.pdf
Manual gives instructions for a different timer dial than timer than shows on unit, so they must come with different dials.

Instructions say pegs pulled out = timer on
Conversely, pegs pushed in = timer off
You might be able to hear the pump operating to see if these instructions are correct for your recirculation timer. The kids would love a listening assignment under the sink.

To see images showing how recirculation system operates:
http://waterheatertimer.org/Water-heater-recirculation-system.html

Setting times:
Try 1/2 hour ON in morning and 1/2 hour ON in evening. Warm water will stay in pipe for a while.

Recirculation system with timer costs $10-17 per year to operate, assuming timer runs 1 hour per day with electric prices at 10 cents per kilowatt hour. Operation cost is straight line ... so if timer runs 2 hours per day, cost is $20-34 per year at 10 cents per Kwh.

Water saved might equal 5 gallons per day, or 1825 gallons per year depending on usage. Average water wasted waiting for hot water is 1/2- 2/3 gallon depending on length of pipe. Set a bucket under spigot to test your home when circulation system is not ON.

Cost of water depends on local billing rate. The municipality saves purifying water, pumping water to your home, and finally pumping and processing sewage drainwater.

If you are on a water well, the pump electricity from saving 2000 gallons a year is a dollar or two per year since water well generally consumes less than 1Kwh per day for ordinary house.

I'd stay with the boiler, electricity to heat water is very expensive. I would not bother with a timed shutoff for the reasons you said. The water will stay hot for some time.

A timer on a conventional electric water heater can save 5-12% on your hot water bill. The water in the tank remains hot for up to eight hours or more while the water heater is not in operation, depending on the insulation and age of the unit. However, the hot water is still available for household use until it is completely consumed. Thus, if a household has a fifty-gallon water heater, it will have fifty-gallons of hot water available while the water heater is not in operation. Most households won't notice the interruption unless they have high hot water use patterns in relation to tank size. It is best to set the timer during hours when hot water use is lowest, typically during the work day or at night. Adjusting the timer may be necessary if households experience a shortage of hot water.