Bosch 1600 h not lighting pilot light

I believe this is a hydro-sparker pilot ignition then burner on when T-Couple/Flame Sensor acknowledges pilot lit.
W/O the signal feedback the Gas Valve will not open and light burner.
This is a Technician Service Job as you have insufficient knowledge to DIY this potentially dangerous LP/NG Control Valve/Sparker Assembly
I assume that lack of knowledge by your lack of a Manual for the Unit
You cannot force ignition on a hydro-sparker manually.

Sounds like you have a hydro-generator on this unit. Check the output on the hydro-generator it should be about 1.5V DC. If not clean the inlet screen and check your water pressure. Water pressure less than 30 PSI will cause issues. If you have 1.2V-1.5V DC make sure the power switch is on. If the power switch is on replace the control unit. I sell parts for Bosch units only!

Call Bosch
Gas Products Technical Support: 800-642-3111

That model number is only shown at one website, and that model number is not shown at Bosch.
Open following link for Bosch:
http://www.boschwaterheater.com/BoschHotWatercomHome/GasProducts/tabid/331/Default.aspx
Search of Bosch for that model number shows no result.

Some water heaters do not have a pilot light. Instead they use hot surface igniter rod that glows red hot
The igniter rod ignites the gas after solenoid valve opens and gas flows to combustion chamber.
The igniter rod and heat sensor have to be operational, and have to be positioned correctly for ignition to take place.
If igniter rod is not working, or if heat sensor does not detect flame, then gas solenoid valve shuts down and water heater does not heat water.

Consult your owners manual.
http://www.bosch.com.au/content/language1/downloads/70R_UserManual1023.pdf
Heres a new one if you don't have or lost yours. You can't, you got bad advice. tankless system don't have a running pilot light. They operate by detecting water flow and then turning on. Many also state on the lighting instructions to NEVER try and manually light the pilot. Try Bosch tech support. Lowes sells Bosch heaters and they might be able to help you get the support number faster. Hope this helps but please don't go sticking a flame inside there.

sounds like the generator has packed up. check water flow and clean any filters on the water line. you will need a service agent to check milli volts on generator and power pack

suggest you complain to Borch sometimes lemons get through best of luck

Make sure the window is big enough. Ok, not funny. Turn the gas on and leave set for 24 hours Light the pilot light and make sure the thermocoupler is at the tip of the flame. hold pilot until the coupler bulb is nice and hot , release the pilot button nice and slow. If the pilot goes out, The thermocoupler is defective. If this sneaking up on it works, then fire up the main burner. Letting the unit sit under the gas pressure for24allows a thorough purging of the main valve. and saturation of any air pockets. Lighting one in cool temperatures is somtimes difficult becase the gas is heavier or more dense than under warm conditions. Sounds dumb, I know. But give it a try and let me know how it goes.Good Luck, Ned

The manual says to hold a match near the pilot while the ignitor is trying. It says that if the unit lights the pilot orifice may be dirty or clogged. Then the manual says to check the voltage on the igniter. It should be 1.3 volts DC minimum if it is not means the electronic control box is defective.

Let me know the status ...Kevin

Aquastar 1600H NG Natural Gas Tankless Water Heater Bosch AquaStar Model 1600H NG Natural Gas Whole house tankless gas water heater, 117,000 Btu input, natural draft with hydro-generated ignition. Provides endless hot water for one major application at a time . Can replace 40-gallon storage tank water heater. Optional Accessory: Model AQ1- Power vent with built-in... More freeze protection when venting horizontally. Capacity: 1 to 2 Bathrooms Dimensions: 8.75D x 18.25 W x 29.75H Weight: 40 Max GPM @ 45F Rise: 4.2 Energy Factor: NG .80 LP .84 Minimum Input: 28,000 Maximum Input: 117,000 Vent Size: 5 Gas Connection: 3/4 Water Connections: 1/2 Warranty: 12-year warranty on heat exchanger, 2-year on parts Features: Endless hot water Can save up to 50% off utility costs annually Perfect for one major application at a time No standing pilot, hydro generated

The clicking is a good sign. What are you trying that not working? How is the water flow-is it strong? 1) Turn the flow control button all the way to your left - this will increase the flow.
2) Pull the relief valve to simulate water flow and listen for clicking sound, and hopefully, main burner ignition. ( if installed in basement or kindly use bucket to catch water) The 1600 H NG will automatically shut off firing after 5sec of clicking.
3) How is the venting-use a household digital carbon monoxoide detector to measure any backspill from chimney.
4) Was the gas line disconnected in anyway after heater was installed? Air in the gas line will cause the igniter to click but no gas to fired the main burner.

Todate i have installed 11 Bosch Tankless Heaters -- 9(125 NG) Which is the same as 1600 Series
1(1600H NG) and 1(1600P NG)
Guess which one I having problem with- You guess it, however, the problem is their electrical wiring.

BE CAREFUL IN CALLNG BOSCH TECH. FOR SUPPORT. THE ARE GRILLING YOU TO FIND A LOOPHOLE WITH YOUR INSTALLATION TO RELIEF THEMSELF OF THEIR WARRANTY.