My leviton timer is flashing on the 10 minute timer. What could be causing this?

The following link has manuals for Leviton timers:
http://waterheatertimer.org/Leviton-timers.html

Is this new installation?
Sounds like timer is wired wrong.
Or you are replacing 3-way switch with the single-pole timer.
Copy following link for step-by-step wiring
http://waterheatertimer.org/How-to-wire-timers.html

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

There are no repairs for electronic wall timers.
Timers have 1 year warranty against defects in workmanship. This sounds like the case here.

Try timer on different circuit and see if same malfunction appears.

Woods is rated for 1/4 HP and will handle bath fan, so load does not sound like a problem.
Timer worked before, so wiring is correct.
Power outages can knock out timers when the power turns on again and timer is exposed to surge.

View countdown timers:
Electronic Leviton 6200 series and Leviton LTB series are more robust than Woods.
Mechanical rotary-type timers have no electronics, and last many years without problems.
Buy locally: GE countdown timers are sold at Home Depot. Advantage of store-bought timer is hassle-free warranty: buy new timer and return defect timer in new package.
http://waterheatertimer.org/Countdown-timer-horsepower-ratings.html

Take a moment and vote on answer:
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

Sounds similar to 6651 timer.
Open following link to identify timer and download manual:
http://waterheatertimer.org/Leviton-timers-and-manuals.html

If timer does not show, add a comment with in-ficus photo of timer posted on Flickr for possible help.

Countdown timers are made to work with bath fans.
Leviton countdown timers are stout product with 1HP rating.
http://waterheatertimer.org/Countdown-timer-horsepower-ratings.html#6200

It sounds like timer is bad.
Wiring sounds good. Make sure you don't have Load and Line wires reversed. Try reversing Load-Line wires and see what happens.
Another thing that affects electronic timers is line noise/interference. If replacement timer does same thing, then noise is suspect. Try timer on another circuit without fan. Try another brand timer. Update to newer LTB60 Leviton timer. Use cheap circuit tester from home center to check outlet on same circuit.

Electrician test wiring before connecting anything.
First of all, you don't mention what type of switch was replaced.

1) Leviton 6230 countdown timer is made to replace single-pole light switch only.
Single pole is where 1 switch controls the Load (light fan motor)

Your wiring sounds like 3-way switch.
3-way is where 2 switches control same Load.
For example a hallway usually has 3-way switches.

To confirm. If old switch has 1 dark screw, 2 brass screws, and 1 green screw, then that is 3-way switch. Use Leviton LTB15, LTB30, LTB60, LTB02, LTB12 countdown timer for 3-way.
Smarthome sells product and shows .pdf manual
http://www.smarthome.com/4255/Leviton-LTB60-1LZ-4-Button-10-20-30-60-Minute-Countdown-Timer-Switch/p.aspx


2) If old switch has 2 brass screws and 1 green screw then that is single-pole switch.

3) If you are replacing single-pole switch, here are testing & wiring instructions for Leviton timer.
Remove device and separate wires for testing.
Use ordinary two wire tester.
Tape tester leads to wood sticks so hands are away from power.
Do not untwist wires that were twisted together before you started.
Turn on power.
Test each wire to bare ground wire.
Tester lights up on Hot wire. This wire will connect to timer black wire.
Now you know Hot wire.
Test Hot wire to each of the other wires, excluding bare ground wire.
Tester lights up on neutral. Timer white wire connects to Neutral wire.
If box does not contain Neutral wire, then timer white wire connects to bare ground.

Timer green wire connects to bare ground wire.
Timer red wire connects to wire going to Load.

First thing to consider is size of Load.
Leviton countdown-timer Load rating is 1800 Watt, 120Volt.
Look inside Jacuzzi at rating plate on motor.
Rating plate on motor should give Volts, Watts and Amps.
Formula Volts x Amps = Watts.
Sometimes motor shows VA which is Watts
Is Jacuzzi on 240Volt breaker or 120V breaker?
Leviton countdown timer is not for 240V load.

A) If 120Volt electric Load checks out, here's how to wire timer if 1 cable enter box.
Timer-black-wire connects to jacuzzi-black
Timer-white-wire connects to ground.
Timer-green connects to ground.
Timer-red connects to jacuzzi-blue.

B) Here's how to wire timer if 2 cables enter box.
120Volt cable coming from breaker box has black, white and bare copper wire.
Timer-black-wire connects to black-wire-from-breaker
Timer-white-wire connects to white-wire-from-breaker-box.
Timer-green and jacuzzi-ground connect to ground

Timer-red-wire connects to jacuzzi-black-wire.

Jacuzzi-blue-wire connects to white.
I am puzzled why this wire is blue if circuit is 120Volt.

The Leviton 6230 is a countdown timer with maximum time of 30 minutes.
The other times are 15minutes, 5minutes and 3minutes.
The timer has a manual override.
Push the bottom button and the timer works like a switch.

Leviton also make the 6260 countdown ... with 10-20-30-60minute times.

Your timer is not desinchronized and can not be set as it is not digital (programmed) type of timer. It is "Hard Wired", that's why the problem is hardware.

Probably it is a dry condenser problem, or a quarz cristal if it's digitalised.

I think that it is rather electrolyte condenser.
If you can not repair it by yourself, take it to a friend it should not be more  expensive than a bottle two of beer.

From this website you can download a free instruction sheet in PDF format...

http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=6216&section=17138