Question about Bosch AquaStar Indoor Natural Gas Tankless Water Heater with Vent Hood #125

1 Answer

Can't regulate water temperature

Bosch Aqua Star Tankless Gas Water Heater D 2400 E (propane) We have had this product for well over a year now. With the temp turned down as low as it will go, we either get scalding hot water or freezing cold water. The water will turn cold if there is some other source of water turned on at the time in the house. It does not matter whether it is cold or hot water turned on in another place in the house.
If we try to adjust the temperature, it will turn ice cold also.

This is not a new problem. It has been this way since the installation.

Is it because there needs to be some sort of flow control valve on either our well or water supply going into the tank less heater?

Please advise us on any ‘fixes’ that we can make to this water heater to make it more like our old ‘conventional’ water heater. Also if you sell the part that may fix this problem, please advise.

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  • Bosch Master
  • 2,458 Answers

Slower the flow hotter the water is how it works . Sounds like the water section is blocked and could well need cleaning out . Draw back with this system is you need a good inlet flow and flow will drop when you open other taps . they are good for a small house a family house not that good . Not much you can do put in a bigger water inlet to heater ?

Posted on Mar 11, 2017

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Posted on Jan 02, 2017

  • 11 Answers

SOURCE: does grundfos rcp96 pump work with bosch 2400 eo tankless heater?

What is your reason to have a recirc line on your water heater does the heater sit to far away from a certain fixture? If you put a pump on your tankless waterheater then your heater will continually fire till the call for hot water is stopped. Yes you normally do need a seperate line installed for a recirc line usually from the water heater to the farthest fixture away. If your problem is taking to long to get hot water then I suggest installing a second heater closer to problem area.

Posted on May 25, 2009

  • 11 Answers

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.
Q. EA - No flame ionization detected with water flow
A.
  1. Verify that all manual gas shut off valves are open.
  2. Verify gas type (See Fig. 2 in installation manual) corresponds with the type of gas supplied to the heater.
  3. Reset error code and open a water tap to cycle the heater in an effort to purge air from gas line (especially on new installations). Cycling hot water tap on and off multiple times may be necessary. If heater still faults with EA error code, have a licensed gas technician properly purge air out of the gas line leading to the water heater.
  4. Verify the three yellow wire connections to the set of electrodes (underside of the burner assembly) are secure.
  5. Verify gas pressure meets specifications outlined in chapter 3.8. See Bulletin TWH-G2-03.
  6. Verify venting meets specifications outlined in chapter 3.6 of the installation manual. Improper venting may cause premature failure of the flame sensor rod.
  7. Observe inside the viewing window of the heat exchanger when a hot water tap is opened. Sparking should be followed by a steady blue flame. If not, Call Bosch Water Heating with observations. Readings from above gas pressure test will be required.
Q. C1 - Fan rotation too low on startup
A.
  1. Disconnect power supply cord. Check wire connections on back side of fan and the two large wire connectors on the control unit. Removal of lower access panel on control unit is necessary to access connectors.
  2. Verify that supply voltage is 120VAC and is properly grounded.
  3. Verify that venting meets specifications outlined in chapter 3.6 of the installation manual. Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure. Verify backdraft flapper inside flue gas collector is not stuck shut.
  4. Check gas pressure. See Bulletin TWH-G2-03. Low gas pressure may cause the fan to change its speed to meet desired temperature.
  5. Possible defective control unit. Call Bosch Water Heating for further instructions.

Posted on Mar 15, 2009

kevin000
  • 1847 Answers

SOURCE: Bosch tankless GWH 1600 H NG won't always ignite

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

Posted on Mar 29, 2009

  • 2 Answers

SOURCE: why am i getting a A3 error code on my bosch aqua

Question is though, why would this fail after only six months?

Posted on Dec 08, 2009

  • 1 Answer

SOURCE: bosch on demand tankless water heater gwh 2400 E LP error code "

BOSH AQ 250 On demand propane water heater ran out of propane, got gas now, but get EC flashing on the display and the unit won't fire? Lost manual, any suggestions. Thanks, Jim

Posted on Feb 23, 2011

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