Do not know how to make the shower get hot

Check and clean the screens on both the hot and cold side, should return to good pressure.

I do not know how old this unit is or what model but many water heaters are not sophisticated enough to measure the temperature, but heat based on water flow and temperature rise. To start, tankless water heaters turn off every time you turn the hot water off. Lets use an example. You use the facilities, wash your hands then turned off the water and take a shower. You will bring the already heated water (from washing your hands) from the pipe up to the shower. Then the cold water that comes into the pipe from the reactivation of the water heater comes up the hot water pipe with warm then hot water just behind.

If this is not your problem, keep reading. Every unit I have been called to see were installed wrong. Check your installation manual to see if the problem with the system started with the contractor.

First, check the temperature of the water from the heater. If it is too hot and you are mixing too much cold water in, the unit will turn off because there is not enough water flow to keep it running.

Second, turn off the valve at the water heater and turn on the hot water at a faucet. If the water does not stop running, there is a "plumbing cross over" usually caused by a failing pressure balance valve in a shower.

Third, if the unit has not been serviced, go to bosch-climate.us to find a tankless water heating professional in your area. Totally Tankless LLC

Are you wanting to change/switch the hot and cold range of the shower or the temperature max and min? As for the range, the Monitor pressure balance valve may be having build up or problems. This valve controls the mixture of hot and cold water. To fix this, you will need to turn off the water supply, take the pipes apart and clean out the valve (I would recommend a professional). As for the max and min, you may just need to check the water heater pressure in your house. It may not be the faucet at all.

Elisa Jed ' http://www.ryansallglass.com/

Could be the pressure on the hot water flow is insufficient, you really need a 5/6 feet head of water from the shower head to the bottom of the storage tank for sufficient pressure.

I would go to the supplier or Manufacture to know who the certified rep is in the area and use them and back charge plumber...

Remove the handle by loosening the screw near the bottom. You should see a plastic ring, probably green, that is the hot water safety. Adjust it so that the handle will turn further for more hot water. It most likely pulls out, then turn it left, reinsert and reattach the handle.

Try draining the system and apply air pressure (min 30psi) to each faucet. Open other hot water faucets to allow pressure to vent. Next try draining and cleaning the hot water tank.

Hello, first if any water supply hot or cold is turned off, you will experience trickling as you mention. You must have both cold and hot in order to adjust the temperature on your valve. if you had a plumber intall this unit you should ask him to adjust it. Otherwise here is how:
Rotate the handle counterclockwise to stop and let water run till cold water is purged, check
temperature. Rotate handle to off, remove handle parts (see Disassembly in your manual) and temperature limit stop, rotate clockwise to decrease and counterclockwise to increase maximum hot water temperature, reinstall temperature limit stop and handle (TIP: Do not screw handle in until desired maximum temperature is achieved) Repeat steps until desired maximum
temperature is achieved

This is a pressure balancing valve that needs both cold and hot water pressure to operated. It is an anti-scald safety operation.

Good Luck, Phil

You could have mineral deposits on the temperature probe inside of the unit. If you remove the heater and purchase a bottle of lime and scale remover (lime away) to put inside of it. Let the unit sit full of water and chemicals for 24 hours. Flush out the unit to remove any residue. You may see the water is brown if you have a lot of buildup. Reconnect unit and test your settings. If this doesn't work, install a anti-scalding device, available at a plumbing supply store.