Tubing size What size cooper tubing can I get away with for a Bosch 1600h-lp heater. The company says 3/4''. Can I go smaller?

If your getting a spark the generator should be ok I would clean the pilot injector and re try

1) Call service technician, and when that person arrives, ask about tips and tricks for maintaining tankless water heater.

2) Open following link for basic troubleshooting resources:
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

3) Add a comment with your experience so others with same problem will benefit.

4) 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, but does not take place of service call since you will be doing the work yourself, on a complicated appliance that is affected by perfect cooperation of internal parts, and external factors.

Make sure water supply not restrcicted, valve partially closed, if on well raise pressure

go to http://www.boschhotwater.com/HelpfulResources/BrochuresManuals/tabid/354/Default.aspx and you can find your manual there. If you have any problems let me know and I will try to get the manual for you. Thx

unplug power or turn off power,reboot, and try again

unplug the unit for 1 to 2 minutes you can usally hear it click off when it is reset,

If you can access the pipe that is clogged, Poor some lime away into it . Let it sit and ad more as needed. the calcium will sofen and ca be flush out. Takes patience. Once you get some flow, fill the tubing with a descaling solution (hardware store) and let it sit. Pool acid works but must be thoroughly flushed out. be careful with acids, always wear gloves.

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

it sounds to me like the dip tube has failed. this is a plastic tube that is inside the water heater on the cold side. It is designed to put the incoming cold water at the bottem of the tank allowing heated water out at the top. when this tube deteriorates the cold water mixes at the top of the tank instead of the bottom. a new dip tube is about 5 bucks but must be inserted on the cold side by someone with plumbing experience.

did you check to see if your temp regulater is working properly? also you have a thermocoupler that senses the heat of the water and works in conjunction with the regulator. have either one or both replaced and the problem will be solved. please rate this thanks