Coffe maker and pulsing lights. "Burst fire" triac control?

Thread Starter

jeffkrol

Joined Dec 8, 2015
11
OK wife bought a new coffee maker.
Made the lights flicker on any circuit we tried (just the one it's on though)
I really mean pulsing since it is patterned not random.

From the above you will deduce we have an older home..

At first thought it was a faulty unit .Exchanged it, same thing.

Before anyone goes off on loose neutrals ect keep in mind in 20 years we only had 2 things ever do this.
One was a curling iron and the other this coffee pot.

Fancy thing that it is it's annoying..and if it was up to me (it isn't ATM) I'd do what I normally do with things that don't work right out of the box.. chuck it..
Anyways for the sake of marital harmony I'm going to try to find a (simpler than rewiring the house) solution to this..

Bit more on this coffee nightmare "symptoms" lights pulse at like 1cps for awhile, go quite and then repeat.
Doesn't matter the kind of light though incandescents show it more (used as test bulbs).. A few of the LED's (need to verify this) we use seem to be immune but not all.

Pretty sure it has a pre-heater that may use the above referenced method (burst fire) of firing up the coil but speculation on my part..

Now what I'm wondering on (unless I can get a consensus and backing this is really a BAD thing, the flicker that is) need others word over mine. Some will understand. :)

After a bunch of err 'research' I was wondering if it's possible to use a transient suppressor (R/C circuit) to alleviate or at least semi- mitigate this issue?
I'm not familiar with them and not publically common enough (i.e. get one at wal-mart) for me to be comfortable enough to just "slap" one on.
Other solution mentioned was a UPS.
Circuit she wants to use has a GFCI on it but no "equipment ground).
Circuit isn't over-loaded AFAICT and flicker occurs w/ almost nothing else on it but 2 LED bulbs (there are more but for testing, not on) , clock, and normally idling projection TV

Believe the main element is 1400W (will check later)

Don't feel like running a line for a stupid coffee pot..:(

Soo..any ideas?

Dang, can't edit titles AFAICT sorry..

Opp's last thing.. It's a 2 prong appliance (no ground) in case that is relevant.
 
Last edited:

Yaakov

Joined Jan 27, 2019
1,612
Your description of the problem, and that a curling iron also did this, makes me concerned for the safety of using that circuit. If the lights are dimming, it means the wires are heating. You are drawing more current than the circuit can handle without limiting. The coffee maker and curling iron are probably rated right at the 15A limit.

It may not be safe to operate these devices on circuits in your older home shared with anything else. It is probably safe to do it alone, but that’s speculation. The circuit should be rated at a minimum of 15A, but who knows?

Bottom line, if not rewiring, running a new circuit from the distribution box would be the safe bet. I’d hate to hear you’d stopped the lights from dimming only to have a fire.
 

Thread Starter

jeffkrol

Joined Dec 8, 2015
11
Your description of the problem, and that a curling iron also did this, makes me concerned for the safety of using that circuit. If the lights are dimming, it means the wires are heating. You are drawing more current than the circuit can handle without limiting. The coffee maker and curling iron are probably rated right at the 15A limit.

It may not be safe to operate these devices on circuits in your older home shared with anything else. It is probably safe to do it alone, but that’s speculation. The circuit should be rated at a minimum of 15A, but who knows?

Bottom line, if not rewiring, running a new circuit from the distribution box would be the safe bet. I’d hate to hear you’d stopped the lights from dimming only to have a fire.
Not that it's perfect but listed as 1450 Watts (12A).
Old coffee pot was listed 1300 Watts (10.8A) w/ no issues noticed..
A 1.2A difference..

Thanks for the advice btw..
 

Thread Starter

jeffkrol

Joined Dec 8, 2015
11
Ran out of edit time.. I'll check the voltage drop in the line. AFAICT you are "allowed" 12V (10%) or less.
Really woudn't LIKE less than a few volts but think that would still be tolerable in this case.. but ???
Last time I checked this circuit (curling iron) voltage drop was about 2V
.2 Ohm..
IF I understand this correctly.

Thought LED's weren't susceptible to this though..but that is another story.
 

Yaakov

Joined Jan 27, 2019
1,612
Not that it's perfect but listed as 1450 Watts (12A).
Old coffee pot was listed 1300 Watts (10.8A) w/ no issues noticed..
A 1.2A difference..

Thanks for the advice btw..
Electrical fires are a real hazard and many homes are lost on account of them. You might find the simply checking the various receptacles and being sure the connections are well made can clear the problem. In theory, this shouldn't be an issue.
 

DbLoud120

Joined May 26, 2014
74
Hello,
You didn't say what model coffee maker that you have but some newer styles that use electronic temperature control use a triac to control the tank heater.

At or near the set temperature the unit pulses the tank heater to help maintain more precise temperature control. In other words, the pulsing is normal.

Your old machine likely used a mechanical thermostat so there would be no pulsing.

This unit should be on a dedicated branch circuit.
 
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