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the AC2 which is on the heater relay board CN1 Pin 2 switches between a Line and N via the Relay on that board
No. Neutral does not play a role in this part of the heater circuit. We’re dealing with a simple relay that is either open or closed. When closed, the heater relay at connects Line from CN1-2 to CN1-3. When open, it’s just like any other open switch: just open. Which means the heater is no longer supplied with Line and so cannot do any work since there is no longer a complete circuit on the Line side of the heater circuit.
I know it will lowest resistance
If you’re saying that current takes the path of least resistance, then I need to correct you on that. This is a half truth. The full truth is that current (a directed stream of electrons) also takes the highest path of resistance. This is why parallel circuits work.
Shunts are a special case because a shunt does not create parallel circuits. Why? Because the shunt itself has no load. What three things do all valid circuits have? 1) power supply 2) a load 3) conductors connecting them together. Shunts, by definition, do not have a load therefore do not create a circuit in themselves. It’s just a jumper wire that is typically used to bypass a load and can reconfigure the larger circuit.
“Since current takes the path of least resistance.”
This is only a half truth. The full truth is that current (a directed stream of electrons) takes ALL valid paths regardless of resistance. The resistance just limits the number of electrons per second (amps, current) going through the load. This is, in fact, why parallel circuits work.
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This reply was modified 3 months ago by
Susan Brown.
If you connect a
positive voltage to the anode (negative side of the diode) and a negative voltage to the cathode
side (positive side of the diode), the diode becomes forward-biased (Figure 7-17a).Good question! Kleinert’s explanation is confusing because he is not talking about the PN junction INSIDE the diode. He is only talking about the EXTERNAL voltage applied to the diode. Hang with me…
PN means “positive-negative.” This is specially “doped” (technical term– that’s what they really call it) semiconductor material INSIDE the diode; half of it is positively doped (has a net positive charge) and half is negatively doped (has a net negative charge). The JUNCTION (where the P and the N material meet– all inside the diode) is the interesting part. The whole trick of semiconductors with PN junctions is either collapsing the junction so the material conducts electrons (current) or expanding the junction so that it blocks electrons.
In a diode, the P-type material (positively doped) is called the anode and the N-type material (negatively doped) is called the cathode. If you apply an EXTERNAL positive charge to the P-type end and a negative EXTERNAL charge to the N-type end, then the PN junction collapses and diode will conduct electrons. This is called “forward biased.” If you switch the external charges and apply a negative charge to the P-type end and a positive charge to the N-type end, then the PN junction expands and electrons cannot get through. This is called “reverse biased.”
With this in mind, here are some resources to watch/read for further elucidation:
1. Read this article on “Diodes in AC circuits”: https://appliantology.org/blogs/entry/1093-diodes-in-ac-circuits/
2. Watch this video on “Diodes in Appliances”: https://appliantology.org/topic/102375-diodes-in-appliances/
3. For a deep dive on semiconductors and PN junctions, watch this webinar: https://appliantology.org/topic/57328-webinar-pn-junctions-and-semiconductors/?do=findComment&comment=339413&_rid=4
When I went to diagnostic after reset the refrigerator I found a frost on the section line.
You should never see frost on the suction line in a properly functioning refrigerator. Frost on the suction line means mixed phase refrigerant (liquid and vapor) is reaching the compressor. The liquid refrigerant can damage the compressor. The inverter (if equipped) will detect this as an overcurrent and kill power to the compressor.
Has this refrigerator sealed system been serviced before? If so, may be an overcharge.
If not, then the heat exchanger (capillary tube adhered to the suction line) may be disrupted.
In a radiant heating element, the thermal limiter is part of the element– it’s the rod you would see sticking inside the element. So the entire element would be replaced.
do I test for amps to see if it’s working properly or am I just testing to see if it is getting power or not.
Remember that power, P, is volts times amps. P=I*E. I don’t carry a watt meter but always carry an amp clamp. So amps are a proxy for watts– if I know the supply voltage and the amps, I know watts. Also remember that loads require watts to function properly. for some loads, like heating elements, you may be given a wattage spec either on tech sheet or on the part itself. If that heating element is not getting hot or not getting hot enough, I’ll proceed this way:
- Identify the heating element circuit on the schematic
- Find a convenient EEPs for that circuit such as at the timer or control board
- Measure voltage supply for that circuit (without voltage, nothing else happens because volts drives amps (electrons))
- If the voltage supply is good, then I measure amps and compare with specs
Here’s where real techs are separated from PCMs. The PCM looks at the manufacturer specs which usually give a resistance spec. I ignore this because they are dumbed-down specs. They do this because they know that most techs don’t understand amps and watts and aren’t comfortable or competent to work on live circuits. But most understand ohms. So they give ohms specs for liability protection because you make an ohm measurement on a dead circuit.
So I measure amps and compare with the wattage spec (which is usually given either on the tech sheet for on the part itself. You usually don’t need to tear down the appliance to get the wattage spec stamped on the part because you can simply look up the part at an online parts site and look at the picture of the label to get the wattage spec). If the amps are in spec, then I know that circuit, including the load, are functioning per design. If amps are too low (usually the case) then I know there’s a problem with a connection in that circuit or the load itself. If amps are zero (and I have a good supply voltage for that circuit) then I know I’m dealing with an open in the circuit somewhere. If you do it this way, measuring resistance of the load is irrelevant.
Remember, too, that a “good” ohms test is not diagnostically conclusive because circuit switches, connections, and loads can (and do!) fail under load (when electrons are moving though the circuit). Ohms testing is ONLY diagnostically conclusive if you measure open. Amps, however, ARE diagnostically conclusive.
If you suspect a switch (such as a hi limit) is failing under load, the best way to test it is NOT ohms! Instead, jump the switch out of the circuit and then run it again to see if you get normal operation. If the circuit works normally, then you have proven the jumped switch is the problem and you replace it. If not, then the problem lies elsewhere.
Ohms are useful in some situations. For example, a dishwasher drain pump in a computer-controlled dishwasher is not working. In this case, the computer may may be sensing a grounded winding in the pump due to current sensing. You would verify this by checking ohms from the pump winding to chassis ground. Should read open. If you get some resistance, even in the K-ohms or M-ohms, then, Houston, we have a situation and you should replace the pump. If the path from winding to ground reads open, then you can confirm the pump is capable of running by using your cheater cord to hot wire the pump. Measure pump amps when you do this. If the pump runs and amps are in spec, then the problem is NOT the pump but instead is the computer board (not supplying voltage to the pump circuit).
Have you watched the video on “Voltage and Voltage Drop, Loads and Switches, Jumpers and Cheater” yet? If you haven’t yet, you will– it’s in the Core course. I explain this in detail in that video.
The service manual does call out a capacitive touch panel. Also had this note about them:
REASSEMBLY NOTE: When reinstalling the User Interface to
the console, only hand tighten the seven (7) hex-head screws
until snug. Using a power driver will strip the screw holes and
stress the capacitive touch user interface.This gives a good clue about how these panels could develop a stuck key error problem. Unlike the panels used in ovens and ranges, this panel is all plastic. This means to can flex and is subject to faults induced by torque stress, such as over tightening the mounting screws. You don’t see this with the glass panels because the glass adds stiffness. If simply overnighting the mounting screws can induce problems in the touch panel, then heat and age can do the same thing. It’s another example of Whirlpool taking a good technology (capacitive touch panels) and implementing it on the cheap (all plastic). These problems could have been prevented by using either thicker plastic or a genuine glass touch panel– both of which would have added stiffness. But no! Whirlpool did it on the cheap to save a nickel per unit in production costs.
Hi Nate,
Are you sure they were both capacitive touch and not membrane panels? Do you have the model numbers so we can see what it shows?
Spraying cleaner on the touch panel would not affect the keypads directly because of the glass barrier. But depending on how the capacitive touch panel was mounted on the UI frame, it’s possible that heavy doses of cleaner could collect at the seam and then wick into the capacitive touch panels reaching the traces creating a short between the traces. Depending on which traces were shorted, the board could read this as a stuck keypad.
Also, cockroaches! Don’t forget about the bugzillas and mice. I’ve seen Thermador range panels stuffed full of cockroaches. Mice can get into places you would never imagine possible.
I don’t understand how a module with one 1 pin for L1 input, in other words a module that performs multi-point spark ignition, can make use of flame sensing.
DSI boards come in two “flavors”: local flame sensing and remote flame sensing. These terms are relative to the flame itself. “Local” flame sensing means there’s a separate flame sensor that is physically placed alongside the spark electrode and is sensing the flame right there at the flame. “Remote” flame sensing means the board is remotely sensing the return current via the chassis. Aside from this variation in flame sensing locality, the board can sense then flame remotely via the same physics of flame rectified current that a multipoint reignition module uses to sense the flame remotely– through chassis return current.
Make sense?
At the 7 minute mark, Mr. Samurai says that the current sent through the burner returns to ground and is sensed by the board.
What would be the purpose of the current being sensed by the board?
The return current is used for flame sensing. Rectified current passes through the flame (called “flame rectification”) to the burner head, through the chassis, and back to the DSI board at the ground terminal. If the board does not sense this flame rectified return current, then it assumes flame as not been established and will continue sending spark voltage to the electrode. If the board does sense the rectified return current, then it stops sending spark voltage to the electrode. The DSI board functions as a reignition module.
Make sense?
when he plugged in the -17 degrees in vacum when he got the sane answer that I got but his was not negative so am I missing a step?
I understand your question. Since the “pressure” we’re talking about in the low side is actually a slight vacuum (something below atmospheric pressure), we use units of inHg (inches of mercury). The only function of the negative sign is to indicate a vacuum. At 17:31, I explicitly say this is a vacuum and write that on the slide.
So you can indicate a vacuum using either the minus sign, meaning “negative pressure” but this is just another way of saying “vacuum.” From a physics standpoint, it doesn’t really make sense to talk about “negative pressure” because pressure is always a force acting on something else. That’s why I don’t like to put a minus sign in front of a “pressure.” But it’s okay to say that as long as we understand in our heads that “negative pressure” really means vacuum. The other more correct way to talk about “negative pressure” is to use the correct term “vacuum.” In this case, we have 1.5 inHg of vacuum which also means 1.5 inHg below standard atmospheric pressure.
Make sense?
The special property of saturation (and ONLY at saturation) is that if you know temperature, you know pressure; if you know pressure, you know temperature. This is because at saturation, pressure and temperature move in lockstep with each other. Outside of saturation (either sub cooling or superheating) pressure and temperature move independently of each other. You can see this most easily on the PH diagram. In the area under the saturation dome, you’ll notice that pressure and temperature move along the same horizontal line.
Also I had a question on the danfoss app in the video the samurai when he plugged in the -17 degrees in vacum when he got the sane answer that I got but his was not negative so am I missing a step?
Please give a time stamp on the video so I can scrub forward to it and take a look.
Dashed lines can indicate a couple of things depending on specifics. A dashed line drawn as a box can indicate optional circuitry or the delineation of a control board. A dashed line connecting two components indicates they are connected by mechanical action. For example, the centrifugal switch in a motor will often have a dashed line connecting the switched to the motor. Here’s an example that shows both:
Hi Ron,
If you haven’t already, start by watching this workshop recording at Appliantology: https://appliantology.org/topic/72423-voltage-voltage-drop-loads-switches-jumpers-cheaters/
ALL switches can be safely jumped for troubleshooting purposes because both sides of the power supply (Line and Neutral) never come together at a switch, only at loads.
Switches come in many different forms and types, including solid state (triacs) and non-solid state (relays and other mechanical switches). Doesn’t matter because they all function the same way: open and close one side a power supply to a load. The key phrase there is “one side of the power supply.” Meaning either Line OR Neutral in an AC circuit or either DC supply OR DC ground in a DC circuit. What you will never ever see is BOTH sides of the power supply coming together at a switch because when the switch closes, you have a dead short.
In your example of jumping then hi-limit and getting a short, the only way this is possible is if you misidentified the wires for the hi limit and accidentally shorted both sides of the power supply together.
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