20 Most Recent Bosch 2400ES LP AquaStar 6.4 GPM Indoor Tankless Liquid Propane Water Heate Questions & Answers

Vibrations were caused by the worn water pump bearings. They could be reduced by reducing the speed of the pump. Vibrations in the water system that is connected to your neighbor may be caused by a change in pressure in the system, if the water pipes are not isolated, and they touch the wall at some oscillation frequency.

Bosch 2400ES LP... | Answered on Nov 05, 2017

You would need to check that you have the correct burner pressure that would be part of the conversion. Its NOT all ways pre-set as some think to the correct pressure .

Bosch 2400ES LP... | Answered on May 29, 2017

We had the same problem - the hot water would only be hot for 3 -5 minutes and shut off, then we had to turn the water off, wait a few minutes, and do it again. VERY FRUSTRATING.

Solution: The Rinnai serviceman showed me the heat-exchanger blower/fan: It was clogged with dust and moths.

Another clue: Our Rinnai was extremely noisy when the heat came on. After the fan was cleaned and replaced, it is nearly silent.

If you are reasonably machanically inclined:

The blower-fan is located in the lower central area of the unit (at least on our unit). If you draw imaginary north-south, east-west lines through the center of the unit, the fan is in the lower-left quadrant. There is a spring clamp securing the black rubber accordian-like tube to the fan. There are two screws that secure the fan to the unit. there are two plugs that connect to the fan, as well as a third air-flow sensor that should be removed. then you can look at the fan unit, as well as the grill on the underside of the heat-exchanger that should be cleaned.

My thought was to go out and get a simple bug-screen, and place it over the air-input outlet vent going outside, but the repair guy said that although it may sound good, if that screen ever gets clogged, or reduces airflow to the Rinnai, then the unit will work harder, or even shut off, giving the same problem,

Bosch 2400ES LP... | Answered on Apr 05, 2013

Problem is not clear

Before calling service technician, open following link for Bosch troubleshooting resources including contact information for Bosch:

Bosch 2400ES LP... | Answered on Jun 09, 2011

You posted under Bosch tankless water heater.
Fixya is ready to assist resourceful do-it-yourselfer, so read information below, and if you are unable to determine what problem is, post another question saying what you've done so far, or contact service technician and when technician arrives, ask that person tricks and tips for maintaining your tankless water heater.

1) Best place to start is troubleshoot section of manual.
Bosch manuals:

2) Open pdf of typical manual: troubleshoot section page 33.

3) BOSCH error codes

4) Bosch has online tech support form:

5) Bosch problems at Fixya:

6) Read manual cover to cover
and make sure maintenance is scheduled.
For example de-liming is recommended each year.
Utube search de-lime tankless water heater

7) Install DIY tank-type gas water heater and avoid the whole headache

Add a comment for more free help.
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.

Bosch 2400ES LP... | Answered on Mar 11, 2011

if it has been constant from instalation it might be that ur shower head is rated too low to get enogh gpm ( gallons per minute) it will tell u most of the time around the shower head where it threads onto the spot of the wall what the gpm is. alot of the energy saver heads are restricting tehgpm to 1.5 or .5 gpms to conserve water well the water heater will only operate correctally around .5 gpm depending on model so if u are not pulling enough water u will not turn the water heater on to get ur hot water all the time so go to lowes ( or locally trusted hardware) and get a new shower head make shure u look for the gpm on teh head and check in ur owners manual to see what gpm ur water heater kicks on

P.S. if ur shower head is rated at higher gpm say 1.5 and it is corroded or pluged up say with lime it is going to restrict it causing a lower gpm

Bosch 2400ES LP... | Answered on Jan 14, 2011

There are a few things that could make it go hot and cold...
First we know that the flame will light or there would be no hot water...
So... either the flame is not being sensed... the flame sensor is bad....
or... the flow switch is acting up and the flow switch is not sensing water flow properly and is shutting the flame down....
I would find the flame sensor first and clean or replace that...
Then I would check the power across the flow switch while water is running...this will tell if the switch is cutting in and out...

If all else fails then the main control could be bad... be that would be the last resort...


Bosch 2400ES LP... | Answered on Dec 19, 2010

Hi. I recommend that you move the thermocouple further into the flame and see if that solves your problem. If it does, fine. If not, replace the thermocouple. J.

Bosch 2400ES LP... | Answered on Jul 05, 2010

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

Bosch 2400ES LP... | Answered on Jun 29, 2010

Have you tried turning off the valves to the water heater and making sure you have no water flow out of the hot water tap? When this happens, often it is because of a problem with a shower cartridge allowing the cold water to cross over into the hot water side. It makes the unit think that the flow has reduced and the heater will turn down or shut off. Then things bounce back and forth Hot to Cold then back to Hot.

Bosch 2400ES LP... | Answered on Apr 05, 2010

Use a hair dryer to warm it.

Bosch 2400ES LP... | Answered on Jan 06, 2010

Yep they make gas pipe for that .Lowes should have it.

Bosch 2400ES LP... | Answered on Mar 15, 2009

This's been a cold year!
Is this an instantaneous water heater?
If it's outside or on an un-insulated wall in an unheated area this could very well be all that's wrong with it!
Is your heater well insulated?
Are your pipes well insulated?
Is it in a heated area?
If not I would insulated it real good and try moving it to an area that's heated!
Has this been helpful?

Bosch 2400ES LP... | Answered on Jan 21, 2009

you can put in a circulatating pump that is controller with a timer and a thermostat so the when yo need heat water the most its readilly available and when you don't it's off, the only thinsg thing that you would have to do it tye in the supply and the return and then insulate the pipes.

Bosch 2400ES LP... | Answered on Dec 26, 2008

Great answer by Steve (I know Steve Spam...real name Richard). Lot of time on his hands (37000 answers).

Can we get real professionals answering questions.

Thank you Richard...let's just call you Dick for short.

Bosch Water... | Answered on Jan 10, 2021

Are you holding the flame button until the thermocouple heats up.

Bosch Water... | Answered on Oct 07, 2019

you dont drain theses type water heaters

Bosch Water... | Answered on Sep 09, 2019

you can not drain these w/ heaters

Bosch Water... | Answered on Sep 08, 2019

first id check shower head most has a screen in them and do get clogged from time to time since the water flows good from faucets

Bosch Water... | Answered on Sep 08, 2019

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