How to repair electric bosch powerstream redring model rp12pt? the heater has been reset and the breaker checked but the red light does not come on and it is not making hot water

SOURCE: Bosch 125 Tankless Water Heater - Water not hot enough

Sounds more like the venturi in the watervalve of the tankless water heater is clogged. I would recommed rebuilding it and paying close attention to properly relubing the pushrod and cleaning the venturi.

SOURCE: A2 error on Bosch tankless water heater

1. Check continuity of the flue gas limiter (see Fig. 63, page 46 of manual). Go to steps two and three to determine air box temperature sensor fault and replace it.
2. Check for flue gas leakage around the top and bottom seals of heat exchanger as well as the viewing window.
3. Check that venting is within specifications (see Section 3.3 of manual). Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.
4. Check that flue gas limiter connector and spade connections are secure.
5. Unplug heater and check the two main plug connections inside the control board.

SOURCE: BOSCH AQUASTAR 2400ES NATURAL GAS TANKLESS HOT WATER HEATER

Q. FA - Gas leakage error, gas valve circuit not closing properly
A.

1. Disconnect power supply cord and check wire connections on gas valve and the two connectors on the control board.
   
2. Flow water out of a hot water tap above the minimum activation point of .8GPM. Measure voltage at the gas valve wire connector. The connector should measure 24VDC between the left pair of wires and 24VDC between the right pair of wires when the unit is operating. If voltage is not correct, contact Bosch Water Heating for further instruction.
   
3. Gas valve may be defective, contact Bosch Water Heating for further instruction.

Ned C Cook

• 3433 Answers
• Posted on May 06, 2009

SOURCE: no hot water, pilot light lights but no burner ignition

Thermo coupler may be defective. it controls the main gas valve by closing main if pilot is out. make sure thermo coupler bulb is positioned over and near tip of pilot flame, but not in the flame. Thermo couplers are inexpensive and easy to change out.

Steven Foerst

• 52 Answers
• Posted on Apr 11, 2010

SOURCE: i have a 250SX aquastar bosch tankless hot water

The 250 MUST have the condensate line connected. EC comes from gas supply problems and CO2 levels not being adjusted. LP units require 3/4" smooth gas pipe or 1" corrugated pipe minimum size. The LP regulator needs to be turned up to about 13 inches of water column and with all the gas appliances on, measure no less than 11 inches of water column. The CO2 levels must be measured by a qualified gas technician with a calibrated (with in 6 months) CO2 analyzer.