Bosch on demand hot water heater

15 years ago

Moved in our new house a few months ago and fell prey to installing an instant natural gas hot water heater.

Originally was going to do a recirculating HW system with 2 conventional tanks.

My wife loves to take loooong showers and for some reason washes clothes, dishes and anything else right before I take a shower, so I thought and endless supply of hot water would be nice.Bosch sounded like a good brand.

So far we are having mixed results.

Our plumber really wanted to put a manifold pipe system in . All the water in the house goes through this and it is distributed out to all individual fixtures with an individual pipe. The big advantage of this is that you can turn any one fixture off at the manifold and still use everything else .The water goes there first , then to the HW heater , then back to the maniifold and then to the point of use. That can take a lot of time !

Also , apparently the Bosch HW heater has to have a certain minimum flow through it , or it wont heat the water.

We live on top of a bluff that is 700 feet higher than the town's water system , so the flow varies and the flow is just ok when at it's best. A few of the faucets (mainly a kitchen Price Pfister seems to have a lot of air mixed in and fills up a gallon jug slowly even though it appears to be a good flow. This is the biggest problem faucet because the hot water heater takes a while to kick in and seems to come and go . When it goes out , then you have to wait for the water to go all through the pipes again. It can literally take 1min 45 seconds for hot water to appear again.

Does anyone have any advice on adjusting the Bosch so that it will heat on a lower flow? Should I install a 300 gal tank and pump so I can have good water flow at all times ?

Should I get rid of the Bosch and go back to 2 80 gal tanks ?

There is no replumbing the house option at this point.

I suppose I could put small 4 gal H20 heaters under all the sinks to add as a buffer.

The one thing I do know is this set up at present is not a viable option.

Open for advice .

Thanks !

PS The Shower works great and it is nice not to have to worry about running out of hot water . We have 3 shower heads . When the pressure is reasonably good , it is wonderful as 2 of them are used as adjustable massage jets.

When the pressure is poor there is not much massage to it.

Sort by:Oldest

Comments (7)

zl700
15 years ago
Unfortunately you fell prey to a Bosch brand tankless. You didnÂt mention which model, but most tend to be insuperior to Takagi or Rinnai. Many people that enter the on-demand/tankless market buy their Bosch from HD or Lowes, not realizing these units are the lowest quality with minimal features and without knowing never get to experience a quality unit and its pluses.

With regards to the manifold system, commonly referred to as a homerun system. Once water comes in, it splits the cold off, then feeds hot water tank at full size which feeds the HW manifold and feeds the fixtures. Because the pipes are much smaller to feed the individual fixtures, hot water is received much faster than a conventional properly sized distribution system.

Some will add a recirc off one leg of manifold, reducing time to get hot water at the manifold and thus you only wait for water down the 3/8" or 1/2" line depending on what it is feeding versus a conventional 3/4" or 1" main hot water line.

With regards to pressure, it would need to be determined if a booster pump will work if enough water is present in supply line to be drawn and pressurized. If not a storage tank that is pressurized/boosted would be necessary
snickster
Original Author
15 years ago
It's a Bosch 2400 E Natural Gas model heater.
Thanks for the info.
You would know I bought the wrong brand !
Argg !
So I guess it's just figuring out where to go from here.
The thing is , it seems to work well with our shower as long as the pressure is good.
I just know we can't stay with the way things are.
Related Discussions
on demand hot water - how long does it take to get hot water?
Q
Comments (3)
The time it takes for the hot water to get to your faucets or shower is related to the distance the water has to travel from the hot water source to the sink and the diameter of the hot water building supply pipe (typically 3/4 inch) as well as the feeder pipe to the sink (typically 1/2 inch). A 3/4 inch pipe holds about 8 ounces of water for every 3 feet of pipe. So if your tank (or tankless) unit is 90 feet away from a faucet, you would have to push out about 1.8 gallons of cold water (plus whatever water is in the feeder pipe, a 6 foot section of 1/2 inch pipe holds about 8 ounces of water) before the hot flows. A typical sink faucet will run at 1.5 gallons per minute maximum flow rate - so you are looking at over 1 minute to get hot water in this scenario. With tankless units, there is also a small delay between the time the unit senses water flowing through it (which triggers it to fire) and the time the unit heats the water up to the set temperature. There are 3 ways you can eliminate the long delay. The first is to put a hot water source (tank or tankless unit) closer to the sinks that are far away from the current source. The second way is to use point of use hot water generators under key sinks that you use. These POU units are very small tanks or tankless units designed to service just once sink. The last method is to install a recirculating loop where you constantly circulate hot water through the hot water building supply. I have a Rinnai tankless system that we installed in the basement directly below the master bathroom. From the time I turn on a shower or sink, hot water is flowing within 10 seconds. That was the good news. The bad news was that the kitchen sink and 3 other sinks that we use often are over 120 feet away from the Rinnai tankless units. Just before we finished the house, we discovered that it was taking several minutes to get hot water at the kitchen sink - and that was unacceptable to us. I wound up installing a recirculting loop. This was not the way I would have preferred to do it, but space and venting in the basement on that side of the house was an issue. You could just live with the delay you have - 1 minute isn't that bad. If you decide to fix the delay, I recommend posting some details on the plumbing forum and seeking advice on how best to correct.
...See More
well water/on demand water heater
Q
Comments (12)
update - did all the checks from Bosch instructions and checked filters on all fixtures in the house. The two fixtures that had most dirty filter were kitchen sink and guest bath sink. The inlet water filter in the heater was a MESS - lots of clay dirt, tiny pieces of grass, and its physical condition is not good so it has to be replaced. We took it out and continue to use the heater as normal until we get replacement. It costs $7, and $7 shipping, so I am going to buy two - for the same cost of shipment - to make it worth the cost. Now that we have big filter in main line , this little one should not have too much work to do. I also changed a rubber washer in our showerhead to open water flow. I know these reducers are designed for city people to reduce their water bill, and we had it in the city, but now we dont need it. All this really opened up water flow and reduced problem but not completely. Right now temp setting is at 104, but the outlet hot water pipe temp reads at 115F. We should still do the multimeter check of the water temp sensors. But I was able to enjoy shower for the first time in longest time. Definately a noticeable improvement so thank you all! also, our PRV does not have a tap to check the pressure, so we will install a gauge in the line, and while we are at it - we will re-arrange the order of filter and PRV.
...See More
Can an on-demand hot water heater solve my problem?
Q
Comments (21)
"I've considered the systems that use the cold water line as a return. There are some concerns about mixing hot water in the cold water lines, since it is not recommended to drink water from the hot side". The amount of water from the hot side pumped into the cold side is diluted and therefore not the same as drinking hot water. "The main concern is legionnaires disease, but others worry about the increased solubility of minerals and other compounds". My wife is an ICP and assured me that the anti-bacterials (chlorine or the like) added in the cold water by our water utility continue to work at a temperature a few degrees over its normal temp and that those same anti-bacterials (chlorine or the like) work just as well in the water heater where the temp is considerably higher than the cold water. I would consider a well water system an entirely different environment since the water is not necessarily safe when pumped from the ground. I can see where Chris8796 would make that statement never having experienced the device in question so here are facts not unsubstantiated opinions... The Laing Autocirc and the Watts version retrofit recirc pumps are NSF certified and not prohibited by any code I can find in the US. This link http://lainginc.itt.com/pdf/ACT303Brochure_web.pdf to the Autocirc brochure lists it's certifications. Living with the Autocirc for 7+ years I never find the temp of the water on the cold side of the sink where the pump is installed to be much above the normal temp of the cold water so any increased solubility is not a consideration and note that no other faucet between the far sink with the device and the WH connects hot and cold. " also got a chuckle from their marketing, "the average family of 4 saves 43 gallons of water a day"? A 3/4" copper pipe holds 0.025 gallons per linear foot and a 1/2" copper pipe holds 0.0121 gallons per linear foot, 43 gallons would fill 1720 feet of 3/4" or 3553 feet of 1/2" pipe. Now, thats a long from the water heater, even if you had to use water 10 times a day". With just two people in a 1600 sq ft home we hit a faucet or appliance far more often than ten times a day and factor in the two plus minutes we used to let the hot water run till it was hot and Laing's claims are in the ballpark. Here are the facts in my first hand experience... no opinion, just fact. My water meter ticks over each 1000 gallons. My average water usage was 4000 gallons per month and every 5th month or so it would drop to 3000 gallons on one months bill then back up to 4000 gallons. With the Laing Autocirc installed the monthly bills dropped to 3000 gallons for four months and then one month at 4000 gallons. That savings coupled with the savings in KCl for my softener (less water used, less softening needed, less KCl used), less LP used to heat the water, and having hot water at the kitchen sink in seconds was a win-win all the way around.
...See More
Condensation inside Takagi On Demand Hot Water Heater
Q
Comments (4)
Unplug it and leave the cover off for a bit and let it dry out. Perhaps even set up a fan or use a hair blow dryer to move things along. Once it's completely dry try plugging it back in and see if it will run. What I strongly suspect is that the unit is cool (inside air conditioned space) and the outside air is very humid and that enough humidity is getting to the unit from the outside air intake to cause this problem. Call Takagi and see if they have a solution (some kind of damper would work) Note: There are some issues that could cause this - a damaged seal around the cover, for example, would allow outside air to move through your unit. Also having the air intake and exhaust located in different areas outside so that there is airflow through the unit when the wind blows is another. Be sure that the seals all around the unit are tight and undamaged.
...See More
jake2007
15 years ago
Okay, I think there are a few things going on here.

One, Bosch had some bad water heaters, particularly the models that used water flow to generate the ignition. Look closely at the amount of water needed to start the heater (spec that's published on the heater). Typically it's .5 gpm. For this unit it's .8 gpm.

You might look at Navien units. The "A" models include a circulating pump and a buffer tank which would solve a lot of your problems. They claim a "0"gpm min flow.

Tankless heaters are great when you do the homework. If you don't, they are likely to disappoint. They aren't a plug and play solution.

Second, You need to look at the pressure / flow problems. Why is air entering the system? Is your Kitchen faucet plugged?
rainbowmike
15 years ago
I have a small Bosch unit, Eco 5, which has been great for 3 years. This morning the ignitor started sparking without any demand, the burner does not go on, just the ignitor clicking away. The unit operates as normal when the hot water tap is turned on. my water is supplied through a pump which is not coming on, ie. no leaks. I changed the batteries hoping that would do it but no luck. Why does the sparking module keep clicking? Help!!!!
jake2007
15 years ago
Hey RainbowMike, this seems like a new thread.

I wasn't able to find an Bosch Eco-5. Is there better information on the model?
rainbowmike
15 years ago
Thanks Jake for responding. I am down in Baja Mexico, and I bought the unit here, all it says is Bosch Eco 5. A friend suggested that the water valve into the unit may be stuck due to the high mineral content of the water we have here. I tapped on the intake connection, a whole lot of powdery stuff fell out and it stopped clicking for a short while and then started again. I think I will get a new unit anyway, 3 years seems to be a reasonable life expectancy for a small unit in a beach house with all the corrosion and minerals. Thanks again
jakethewonderdog
15 years ago
You might try vinegar before you start over. It's acidic enough to clean a lot of the scale out of the system.

Bosch on demand hot water heater

Comments (7)

zl700

snickster
Original Author

Related Discussions

jake2007

rainbowmike

jake2007

rainbowmike

jakethewonderdog

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Bosch on demand hot water heater

Comments (7)

zl700

snicksterOriginal Author

Related Discussions

jake2007

rainbowmike

jake2007

rainbowmike

jakethewonderdog

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

snickster
Original Author