Question about Water Heaters

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Have an electric Power Star tankless hot water heater, PS28T. Have had on-going problems with lack of continuous heat as well as having to replace elements regularly. The last replacement was 2 months ago. Now both the left and right element lights have gone off! I apparently do not have a local repair person who knows anything about them. I do have a plumber who has helped just by replacing the elements but he doesn't know why the elements keep going out. Most of the elements have had the metal coil in the element broken but some have not. There does not appear to be any buildup on the element. There is minimal hot water use in my house since I'm single and mostly wash clothes in cold water. I only run the dishwasher every five days or so but do take a bath daily. I'm really frustrated. Can you help!! Carole from Missouri

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  • cmhayes Apr 18, 2009

    I have the instruction book and both my plumber and I have read it. Everything appears to be set correctly and it has worked properly previously. No "troubleshooting" comments appear to be applicable. Elements are new. The referral to only discussed "regular" hotwater heaters, not tankless ones.



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CLICK HERE for the Owners manual to your unit.

It is my experience that a unit with a high element failure rate is primarily due to the thermostat being improperly set... and the element heats up to maximumm ALL THE TIME.

To set the thermostat properly -

a) Flow enough hot water to activate unit. The indicator light on the black flow control board
should illuminate.
b) Further increase the hot water flow and the indicator light o n the clear thermostatic board
to the left of the black board should illuminate. Note: This light should pulse On and Off at
first and after about 20- 30 seconds it should stay fully on.
c) Further increase the hot water flow and the indicator light o n the next clear thermostatic
board (PS28T model only) should illuminate. Note: This light should pulse On and Off at
first and after about 20- 30 seconds it should stay fully on.
d) Set (PS19T) thermostat to achieve the desired outlet temperature.
Set both (PS28T) thermostats to the same position to achieve the desired outlet temp.
e) The thermostat is now set and the water temperature will alwa ys be the same when the
indicator light is pulsing.
f) Increasing water flow (above the flow rate at which the thermostatic control is no longer
effective) will reduce the water temperature.

If a lower temperature is required for the PS19T, turn the temperature adjustment screw
counter-clockwise about 1/8 of a turn (See pages 3 & 4 for adjustment location). Wait 15-20
seconds and check the temperature at the fixture. Repeat this process until the desired
temperature has been achieved.
For PS28T model try to adjust the 2 temperature adjustment screws by about the same
amount so that the lights pulse at the same rate. If you have reduced the temperature
considerably from the 140 F setting, you could now open up the o utlet ball valve slightly to achieve
a higher rate of flow.
When the indicator light is on continuously, the unit is emitting full power. When it is pulsing, the
unit is modulating the power to achieve the temperature set by means of the temperature
adjustment screw.
In order to obtain good control at “single lever” mixer type faucets (single spout) the cold water
supply to the faucet should be restricted to give approximately the same flow rate of cold water
to the faucet as the hot water coming from your Powerstar heater. The simplest method of
doing this is by partially closing the cold water valve under the sink.

Also - since the plumber does not have knowledge of tankless heaters - be sure that once elements are replaced - that the water is turned on for a few minutes BEFORE powering up the heater. Water pockets can develop around or inside the heating element tube and burn out the element prematurely. it must be surrounded FULLY by water at all times when heating.

You havent told the age of the heater - but there may also be sediment buildup around where the element is inserted that does not allow water to fully encompass the element as well.

Next time you have them out - make sure there isnt a pocket of lime where the element is.

Thanks for using FixYa !!
If you need further clarification about your question - please use the "continue with this expert" option so we are connected in the future.

Thank You!! :D

Posted on Apr 18, 2009

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Hi Carole,

Please find the instruction manual for your type of heater in the bellow link:

Keep this handy as it's instructions will help u from time to time.

Also please find a detailed troubleshooting of various parts of the heater ( primarily the elements) in the bellow mentioned links.


Have a nice day.

Posted on Apr 13, 2009


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