Tankless Hot Water Heater (Water not hot enough)


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Old 12-21-07, 08:18 AM
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Tankless Hot Water Heater (Water not hot enough)

I have a Bosch 125 X Natural Gas Instant Hot Water Heater. Ive had it for years, and I know how it works, etc. Lately, the water from my tap is not hot enough. I've checked input filter screen for clogging. I've checked the spigots for the same problem. I've rebult the water valve. I've adjusted the gas/flow ratio screw on the front of the unit. I've not yet checked the Gas pressure, but everything else gas in the house works just fine. Any thoughts to make it hotter would be appreciated. Thanks.
 
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Old 12-21-07, 05:07 PM
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I'm told that flow switches tend to wear out after about five years or so and need replacing. That should at least be looked at. All tankless units whether theybe electric (save one) or gas utilize flow switches. Those switches basically help determine how hot the unit is to heat the water.

On electric models, the flow switch turns on/off the heating thermostats. I think gas works about the same way. Get a Bosh repair person out to run some checks.
 
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Old 12-31-07, 06:58 PM
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Yeah. I know all about that hot and cold water!
My "American" electricTankless(It is made in China of course) is constantly changing temp as the water pressure goes up and down. I am told there is something you can add to your pump to correct this problem?
 
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Old 01-01-08, 08:48 AM
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Hey roadhawg3...who made yours? I know there is a unit sold in Arizona that doesn't use flow switches. It's the only one, from what I can determine.

Mine is a SETS and I had a little trouble with temp fluctuation. I put two spacers each between the plate that holds the three thermostats and the heat chambers to get more clearance. The heat sink just wasn't doing the job. SETS recommended that I actually pry the plate away from the chamber but screws seemed to be a better and more even solution to get them away from the heating chambers.

Those things are sensitive enough that one degree can make the difference between the thermostat turning on and off. Mine has been working very well since doing that. A screwdriver, long and thin needlenose pliers for the tight places and two washers each for the number of screws and you should see an improvement. It has worked for me, at least.

If it is a flow problem and you are constantly changing the flow, then there will be fluctuations, also. If it occurs in the shower, then you might need to remove the flow restrictors. SETS recommended that in the manual.
 
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Old 01-26-08, 11:11 AM
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SETS water heater temp variations...

Any chance of getting a photo of this fix? Thanks...

Mine is a SETS and I had a little trouble with temp fluctuation. I put two spacers each between the plate that holds the three thermostats and the heat chambers to get more clearance. The heat sink just wasn't doing the job. SETS recommended that I actually pry the plate away from the chamber but screws seemed to be a better and more even solution to get them away from the heating chambers.

Those things are sensitive enough that one degree can make the difference between the thermostat turning on and off. Mine has been working very well since doing that. A screwdriver, long and thin needlenose pliers for the tight places and two washers each for the number of screws and you should see an improvement. It has worked for me, at least.
 
 

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