Question about Bosch & Tankless LP Hot Water Heater

3 Answers

Water turns cold very quickly

When our Bosch tankless water heater was installed last winter, it worked great. The hot water now warms up as usual but turns cold within a couple of minutes. We have to turn the water off for a few seconds and then back on and it will get warm again but doesn't last very long. It is very frustrating to be in the shower and the hot water turns cold within a couple of minutes.

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I had the EXACT same problem (installed my tankless last winter and worked fine, now this summer it fluctuates, have to turn the shower completely off and then on again to get any hot water and then it only lasts for a couple of minutes!) Argh - it is frustrating!

Here's what I found: the demand for hot water is lower during the summer (hot) months because the "cold" water coming in is already quite warm. You don't need as much hot water to make the shower temp comfortable. SO, my tankless was shutting off due to low flow demand. I've removed the flow restrictor from my shower head and it helped alot but didn't completely solve the prob. Next step is what has been recommended to me by several people but is much more expensive - change the pressure valve on your shower to a temperature valve. Or just wait til winter and it should work ok again :)

Posted on Aug 20, 2010

Testimonial: "I will give that a try because it is a long time until winter! Thanks."

  • ellync Aug 24, 2010

    I just figured out that my shower head had two flow restrictors - I have a hand held (good for washing the golden retriever :) ) and there is a restrictor in the hand held part and in the part that is connected to the wall. I've now removed them both and I have triple the flow and no hot water shut-offs!! Hooray! Hope it worked for you :)

  • howtodoit Aug 27, 2010

    ellync,

    Thanks for the tip. I have the exact same shower problem with my tankless heater. You menteioned that you've removed flow restrictors. Are you talking about the Screen Gaskets?

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What is the model of your Bosch water heater?

Posted on Jul 26, 2010

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It is likely that you purchased a tankless hot water heater with a lower flow rating than needed. Tankless water heaters are rated to provide hot water at a designated flow level. There is a good chance that your shower uses the water faster than your tankless water heater can heat it up.
Either get a beefier heater capable of heating up more water faster, or purchase a low-flow shower head. I would go with the shower head as it is much cheaper and you'll actually save money as you saver water too.

Posted on Jul 17, 2010

  • mushrooman Sep 25, 2010

    Sorry guys , I think you all may be wrong ,
    Mines the same .
    Its about 12 years old and was given to me.
    It turned out to be the diaphram in the regulator is broken.
    Its job is to push the gas pressure up .
    Being made of rubber it will push the pressure up but it comes down slowly .
    You can buy a diaphram at the plumbers supply for abt $30 and do yourself or pay a gassy. $250 or so,

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Posted on Jan 02, 2017

1stBSP
  • 52 Answers

SOURCE: bosch tankless heater flucuates hot cold?

It sounds like you have a plumbing cross over or a poor install. Check boschhotwater.com to find a service technician and have a Bosch service provider look at it.

Posted on Apr 11, 2010

  • 34 Answers

SOURCE: I have a newly installed Bosch hot water heater.

these units need lots of flow to start and run. Set the temp on the unit lower and the people in the shower will have to use more hot and less cold which will make the unit more stable.

Posted on Jun 07, 2010

  • 643 Answers

SOURCE: Bosch Pro Tankless - Shows error code E4 - every

E4 error code on Bosch tank less hot water heater, this is what it says.....

E4: Backflow temperature sensor over 309°F. The appliance will close the burner and lock.
A.
Check combustion air and backflow vent piping for blockage.
Check if secondary fan connections are disconnected.
Check venting specifications are met. Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.
Check sensor resistance (see Fig. 61, page 44 in manual).

Posted on Jul 09, 2011

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2 Answers

Hot water varies


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

Mar 14, 2014 | Bosch & Tankless LP Hot Water Heater

1 Answer

I have a Bosch Powerstar Ae115 and the left cutout keeps tripping. It has worked great for 5 years. When i reset it, the water gets warm again(never hot as it was before). What could be causing it to trip?


Water leaking into elements. Bad PC board. Undersized breakers. Undersized main panel.
Bosch Powerstar is a computer that happens to heat water.
If your 5-year-old laptop computer was malfunctioning, you would not be surprised.
But for some reason (false marketing by manufacturers?), folks believe a tankless computer is going to last 20 years.
Moreover folks also believe tankless will provide endless hot water while saving money.
The whole idea of tankless saving money is a load of sales-BS that defies physics and common sense.
There are no service manuals... except bosch website has troubleshoot section in product manual.
Call a bosch-qualified service tech.
Go to Lowes and buy ordinary tank heater, and fix your heater today for only $250.
Tank-type electric water heater can be easily repaired and maintained by homeowner to last forever... that is a fact
http://waterheatertimer.org/How-to-maintain-water-heater.html

http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater.html

Gene

Jan 12, 2014 | Water Heaters

1 Answer

There is power to the system but when you turn water on elements do not come one and heat water. all phases have 238 volts to them. why will system not turn on and heat water


Do you have 3-phase water heater? Is this balanced or unbalanced 3-phase unit. Add comment and describe product in detail, including brand since i have some service resources for both types.
Or do you have ordinary residential split-phase 240Volt Bosch tankless computer that heats water, and has 2 or 3 separate elements, and a separate circuit breaker supplying power to each element? And testing across both hot leads coming from each breaker yields 238Volt?
Copy following link for Bosch tankless manuals, with brief troubleshoot section that does not provide detailed service procedures for repairing tankless computer:
http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater.html#manual
If this is new water heater, then call installer. If you installed yourself, then remove tankless and return to seller for refund.
Tankless computers require certain amount of water flow to activate computer sensors. Turn on Hot tap and listen to pipe to hear if water if flowing through hot pipe. Check for crossover:
http://waterheatertimer.org/Crossover.html
Clean water filter usually located just above where cold water connects to unit.
Delime tankless ... and use water softener. Tankless cannot be exposed to more than 11 grains hardness in water, or parts will fail within 2-3 years. Simply deliming tankless heat exchanger each year will not maintain full efficiency... although for typical family of 4, tankless comper water heater costs $100 more to operate than tank-type heater according to manufacturer's promo literature and independent studies.
Call local technician who specializes in fixing tankless computers. For plumbing problems call local plumber. These are two different things.
If tankless computer is older, then cut losses, and buy tank-type electric water heater at Lowes for $285 and make quick changeover and have hot water same day. Sell old tankless on ebay and cheat next guy, or sell at scrapyard for $3 per 100.
Gene
h

Aug 05, 2013 | Bosch PowerStar AE125 AE125 Whole House...

1 Answer

Bosch gwh 425 hn


Fix problem immediately same day, yourself, for $385, by replacing whole thing:
http://waterheatertimer.org/How-to-install-gas-water-heater.html
Bosch posts some service manuals: or contact Bosch. Lack of error code indicates failed PC board? or bad single-handle faucet cartridge?
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html
Check for crossover where bad faucet cartridge allows cold water to enter hot pipe, so hot water is not drawn through tankless and burner does not activate... but this might not be problem since you hear the tankless clicking
http://waterheatertimer.org/Crossover.html
Call local service technician to catch up on required yearly maintenance.

Jun 09, 2013 | Water Heaters

1 Answer

Tankless water heater doesn't produce hot water in the winter when tempetures are below 32 degrees. I tried a water saver shower head and this worked for a little while. Anything else I can do ?


1) Tempering tank might help:
http://waterheatertimer.org/Tempering-tank.html

2) Reduce temperature setting on tankless unit so there is less differential between incoming cold water and thermostat set point.

3) Absolutely any tankless problem can be solved same day by installing tank-type gas water heater:
http://waterheatertimer.org/How-to-install-gas-water-heater.html

4) Add comment and say what you do to solve problem.

Jan 31, 2013 | Bosch AquaStar 2400ES-NG

1 Answer

How do you insulate a tankless water heater for winter


If you have tankless electric, it can simply be insulated... but tankless electric are seldom mounted outdoor.
Service bulletin says: "the only way of assuring protection is to completely remove the heater during those times the area may experience freezing temperatures.

There are tankless with built-in heater for exterior installation.
Check your manual, or add a comment with specific model number and maybe I can find the information.

Here's why they install tankless outdoors: Because tankless burn more fuel per gallon of hot water. This requires larger gas line and larger vent pipe than typical tank-type gas water heater that is usually installed indoors.
They install tankless outdoors, so there is no need for expensive vent pipe, and because there is ample incoming air to support combustion.
So if tankless does not have factory-installed internal heater, then the unit can freeze easily when the combustion draws in cold air.
Of course you can put heat-tapes on the pipes but the heat exchanger inside will quickly freeze during periods when hot water is not being used, and combustion is not taking place.

You can move the tankless installation inside and use correctly-sized vent and intake pipes directly through the wall. This will generally protect tanklesss from freezing if room is heated adequately.

Sep 26, 2012 | Rinnai Webstone The isolator EXP tankless...

1 Answer

Will not fire at all, trys to light but get the e1 code . used to work intermitently or fire right of way but then go cold and back to hot for about five min. then stay hot now wont even light


Before calling service technician, open following links for troubleshoot resources:
http://waterheatertimer.org/pdf/Bosch_E1_troubleshooting.pdf
http://www.bosch-climate.us/bosch-hot-water/aquastar-service-bulletins/
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html
http://waterheatertimer.org/Crossover.html

Before installing tankless water heater, read the service manuals and product manual to make sure you have testing skills and equipment needed to repair tankless gas water heater, and that you are prepared to buy expensive parts when needed and do the recommended yearly and monthly maintenance as outlined in manual.
Also check that area has qualified service technician, and that person carries parts on-hand, and is certified for your model number. Keep Tankless manufacturer contact information on-hand, and be skeptical of promises of unlimited hot water, and effortless long-lasting water heating, and saving money. The only folks saying this are the folks selling the product, and not their customers.

Fix most tankless gas water heaters yourself, same day, all brads for about $350.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Sep 21, 2011 | Bosch Water Heaters AquaStar 250SXO...

1 Answer

Hi, I have the 1600 NG tankless water heater. Everything works great, but I installed low flow hot faucets throughout the house and now the igniter will not click on. It works for the washing machine. ...


http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html#flow
1) Tankless require minimum flow rate before burner will activate.
2) Sounds like the water pressure drops quickly when faucet turns on. This implies combination of problems including sediment build up inside lines, crossover at single-handled faucet, or sediment filter clogged or water softener clogged.
3) Low flow faucets can reduce needed flow rate.
4) Other problems can contribute: sensor failure, loose wires, PC board failure, high temperature setting, cold incoming water temperature during winter months.

Jul 20, 2011 | Bosch 1600H-NG Natural Gas AquaStar...

1 Answer

I have a Bosch 250sx NG I hired a plumber to install. I have 3/4 water and 3/4 gas line to unit. When turned to hot the water is cooking, turned down it is great,,, almost. My water will turn cold for...


Before calling service technician, open following link for Bosch troubleshooting steps.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

If you are not getting error code, then problem could be somewhere in plumbing, as you suspect.
For example cross-over on single-handled faucet, or faulty check valve on re-circulation system, or sediment clog at elbow, or varied water-well pressure. Install in-line pressure tank.
http://waterheatertimer.org/pdf/Bosch_Overcoming_fluctuating_temps.pdf
http://waterheatertimer.org/pdf/No-Error-Code.pdf

Be sure to read manual for yearly maintenance protocol.
Tankless must be maintained, and cannot be exposed to hardness in water greater than 11 grains, and should be de-limed each year. Expect maintenance, service, and potential repairs and parts for tankless to far exceed expected $1-8 monthly savings. All costs are energy.

All gas tankless brands can be repaired by homeowner for $330.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Apr 22, 2011 | Bosch Water Heaters

1 Answer

Bosch tankless heater flucuates hot cold?


It sounds like you have a plumbing cross over or a poor install. Check boschhotwater.com to find a service technician and have a Bosch service provider look at it.

Mar 06, 2010 | Bosch & Tankless LP Hot Water Heater

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