[groetschel72]

Hello
I installed a Ranein Tankless Water Heater 18kw for my infloor heating system yesterday. It requires 2 x 40 amp breakers. The heater is just 4 meters away from the breaker box. I used the recommended 8/2 awg wires. My breaker box has a 200 amp service. If I understand it correctly, 18000 watts / 240 volts = 75 amp, which shouldn’t be a problem for my 200 amp service. I also checked all other higher amp services and made sure they are turned off.

But the lights in the house are flickering!!!

I googled the problem and found it is a known problem if the heater draws too much power for the breaker box (voltage drop), but this is not the case here.

Any ideas how to fix this problem?

THANKS
Gunnar

 

[AllanJ]

The sudden 70 odd ampere draw by the water heater could be enough to make a voltage drop, although still within acceptable 3% standards, enough to cause incandescent lights to dim noticeably. Other kinds of lights including some brands of LEDs might be sensitive enough, at the exact voltage they are getting, to dim noticeably or flicker also.

Power companies have different rules for wire size for the 120/240 volt power from the pole transformer and strung between utility poles and across your yard or driveway to your service entrance. There might be more voltage drop than you might expect in that stretch of wiring.

You might want to measure the exact voltage before and after the heater kicks on. Some wires with alligator clips on the ends, that the former Radio Shack used to sell and Amazon now does sell, could come in handy.

 

[Chris616]

Edit again: After having some coffee I can see that I was not thinking straight. Your two 240V breakers are each already connected to both busbars, so disregard everything that I've written except post #7.

 

[groetschel72]

The sudden 70 odd ampere draw by the water heater could be enough to make a voltage drop in the stretch from pole transformer to panel, although still within acceptable 3% standards, enough to cause incandescent lights to dim noticeably. Other kinds of lights including some brands of LEDs might be sensitive enough, at the exact voltage they are getting, to dim noticeably or flicker also.

Power companies have different rules for wire size for the 120/240 volt power strung between utility poles and across your yard or driveway to your service entrance. There might be more voltage drop than you might expect in that stretch of wiring.

You might want to measure the exact voltage before and after the heater kicks on. Some wires with alligator clips on the ends, that the former Radio Shack used to sell and Amazon now does sell, could come in handy.

So, the solution would be to change all LED lights in the house? Do you have a recommendation for working LEDs? I am currently using the light bulbs from Costco.

 

[groetschel72]

Are any of the flicking lights connected to breakers on the right side of the panel? You have the two heater breakers connected to the same bus bar.

Shall I try to move one of the breakers from the left to the right side of the panel?

 

[Chris616]

Shall I try to move one of the breakers from the left to the right side of the panel?

After having some coffee I can see that I was "out to lunch" on my earlier comment, so disregard my previous post.

 

[Chris616]

It's unrelated to your question, but you might be interested in reading this recent thread about Federal Pioneer Stab-Lok panels.

https://www.diychatroom.com/threads/do-we-have-to-change-our-breaker-panel.776477/?post_id=7225404#post-7225404

 

[AllanJ]

The heater would be wired to two double breakers or four single breakers. If single breakers the installation guide will suggest them wired up as pairs.

I suspect that the breakers for your heater were already correctly placed in the panel where you got 240 volts within each pair. If not, a pair would have zero volts between them, no power would be drawn, and I trust that insufficent power would be drawn altogether to cause any light dimming.

 

[groetschel72]

Yes, the heater is wired to two double pole breakers. And since each provides 240 volts the breakers are connected to both busses.

 

[Missouri Bound]

Flickering is sometime caused by loose connections....not necessarily of your new heater but anywhere and including the main lugs to each circuit. Is your home all electric...range, water heater, dryer etc?
What is the capacity of your electric panel?
What is the age of your panel?
And of course there is always the usual comments about Stab-Lok breakers and equipment which seem to have concerned many people.

 

[AllanJ]

Take oue one of the bulbs that flickers and put it in a portable lamp fixture. Move that fixture around to different rooms, plug it in and find out what brahch circuits (what receptacles) it does not flicker.

Is the a receptacle within 10 feet of the primary panel or load center in the basement? Plug in the light fixture there, does it flicker?

 

[groetschel72]

Flickering is sometime caused by loose connections....not necessarily of your new heater but anywhere and including the main lugs to each circuit. Is your home all electric...range, water heater, dryer etc?
What is the capacity of your electric panel?
What is the age of your panel?
And of course there is always the usual comments about Stab-Lok breakers and equipment which seem to have concerned many people.

Thanks for your message. My panel has a 200 amp capacity. I don't think it is caused by a loose connection. If I switch the two double pole breakers off, no flickering. If I switch them on and heater draws power, flickering.

 

[groetschel72]

Take oue one of the bulbs that flickers and put it in a portable lamp fixture. Move that fixture around to different rooms, plug it in and find out what brahch circuits (what receptacles) it does not flicker.

Is the a receptacle within 10 feet of the primary panel or load center in the basement? Plug in the light fixture there, does it flicker?

Thanks. I did what you suggested. The flickering is most vital in the utility room (where the breaker panel is). I tested receptacles throughout the house, and all are flickering. I have the feeling that the further away I get, the less it flickers. Does this make sense?

 

[Jim Port]

Any marginal connection with get worse under a heavy load. It could be upstream in the panel.

 

[AllanJ]

The voltage perturbation (rise and fall) is occurring in wiring that is common to all of the locations where you plugged in the test light. That is, the problem is occurring in or upstream of the primary panel.

 

[Missouri Bound]

What are you calling a "flicker"
A constant pulse or just a bit when the heater kicks on and off?
The website has very little technical information but it says that it "intelligent constant temperature"
If that is accomplished by rapidly cycling the heater off and on.....then it make sense how it could cause a flicker in some electrical circuits.
Let me ask you this.....when you first started it up....did it flicker or did that start after it got to the set temperature?

 

[dcwired4]

If you have one, use a digital volt meter to check voltage at the feed to the panel across the 2 hots. With heater on, any fluctuations. If so, the issue is in connections possibly in the meter, drop to the weatherhead (overhead), or at the pole ( the Poco's issue).

 

[groetschel72]

The voltage perturbation (rise and fall) is occurring in wiring that is common to all of the locations where you plugged in the test light. That is, the problem is occurring in or upstream of the primary panel.

Thanks. I will Have an electrician coming in and check everything. I am going to report back what the problem was.

 

[Missouri Bound]

Thanks. I will Have an electrician coming in and check everything. I am going to report back what the problem was.

Thank you for that. It is appreciated.

 

[groetschel72]

You ask good questions.
I call “flicker” a very little dim in the light for about 1 sec and then 1 sec back to normal -pulsing. Hmm, I only noticed it when the water has reached the desired temperature. I will have an electrician coming in and check what’s going on. Thanks again.