Question about Noritz 8.4 Gallon Residential Direct Vent Tankless Water Heater - N

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Unit flashes the number 20

Does not operate when flashing 20, lets water through fine but it's not hot. If I unplug the unit(electricity) then plug back in it works normal for a while then reverts back the the flashing 20 agian. the number 20 is not in the manual as a trouble shooting number.

also the red light on the front panel of unit flashes 4 times.

what does this mean?

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A 20 error code means the high limit switch is being tripped. This is most typically caused when scale develops in the heat exchanger. I'd recommend performing a descale on the heater to resolve the problem. Make sure to follow the instructions that came with your isolator valve kit.

Posted on Jul 12, 2010

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Got hot water for a little while then stop geting hot water

If you have a gas water heater and its a few years old and it has an electric fan for exhaust unplug the fan motor from out let and plug it in again this will rest your hot water computer and sensors. If the burner comes on which you will hear right away,, then it means your flame sensor needs cleaning its a 3 inch rod its infront of the door opening or water control below,,, slide cover off and one screw is holding the flame sensor rod. also look for a flashing red light down by the cntrols if it is flashing call a service man, in you need a computer board or module replaced if its a rental?,, its free. Please if this is Gas if you are not sure Call service man right away if its electric water heater Call for service likwise dont attempt repairs unless you need to rest your fuse on the electrical panel. Careful please lives could be in danger if you attempt anything you are not sure of Dont touch it!



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I would like to know the electrical requirements.( voltage and amperage) Does it plug in or is it hard wired? If the power goes out is the hot water also out? thankyou

Are you asking about tankless gas or tankless electric?

You posted under Tankless gas water heater: gas type tankless plugs into standard 120Volt household outlet to power circuit board. You need larger gas line than used for tank-type gas water heater.

If you are asking about volt and amp draw of Tankless electric, then that depends on specific model number.
For example, if each tankless element draws 3500Watts, and unit has 3 elements, you will need 3 additional 20 amp 240Volt circuit breakers. Volts x amps = watts. 3500 watts divided by 240Volts = 14.58 amps. At full blast, this unit would draw 43.75 amps and will cost more to operate yearly than tank-type electric water heater. If unit has 4500 watts elements, then it will draw 56 amps at full blast, and use a good percentage of household power.

Tankless water heaters have no hot water in power outage. This is true for gas and electric models.

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2 green flashes. hot water is blazing hot set at 120 degrees.have the energy smart unit model#ee2h50rd045v . what is wrong?

2 green flashes is 'High Water Temp.'

Typical energy smart manual:

3 flashes is Temperature Sensor failure.
4 flashes is Upper element
5 flashes is Lower element

Troubleshoot section says:
1) Make sure access doors and insulation are installed.
2) Check elements for resistance of 5-25 ohms (if element has a short in center of element, it might not trip breaker)
3) replace element and reset control system.
Buy ordinary 4500 Watt element from hardware store.

4) I also suspect the self-diagnostic control box.
Manual says: Repair parts may be ordered through your plumber,
local distributor, home improvement center, or by calling
You need serial number, product number and model number from label on side of tank.

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If there is an electricity failure how can we have a hot shower

Easy answer is you cant on these units. These tankless units store no hot water and need a 240V power supply to operate.

In some areas in far north Queensland I came up with a back up power unit (I used to work for Rinnai who make similar units). These were for remote units that used battery lighting and just wanted a bit of hot water for remote workers.

Basically you need a spare car batttery and an electrical inverter or a back up petrol generator. These hot water units only use a very small amount of electrical power even when that are operating. I had a guy run the hot water for nearly two weeks on a car battery and inverter after cycone Larry hit Innisfail in North Queensland.

Depends how often you get power losses as to how much money you want to spend to cover yourself (99.9999% don't bother with no real hassles).

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check the wiring connections for your remote. The FF is related to communication problems with the remote. You should also reset the unit by disconnecting electricity, waiting 20 seconds, and then reconnecting electricity to the heater.

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Sometimes the hot water just goes cold

Here are a couple things to look for:

1) flashing burner light - a flashing burner light indicates the unit is getting an error code
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B. 3 flashes - error 16, abnormal outlet water temperature; typically this code indicates you'll need to descale you unit
C. 4 or 5 flashes - exotic error codes; you should contact Noritz technical support to deal with these codes

2. If there is no flashing code, try increasing the hot water flow. In the summer time you typically use less hot water; this can result in intermittent operation of your tankless heater. Increase water flow by either: A. cleaning your showerhead and removing scale deposits B. widening your flow restrictor C. Remove your flow restrictor in the showerhead

3.If none of these resolves your problem, you probably have debris in your flow sensor. Contact Noritz technical support for a walkthrough on removing debris from a flow sensor.

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