Chattering at this relay control or contactor switch would be unusual; if it occurs you should shut off the circuit immediately to reduce the risk of an electrical fire. Watch out : while a single on-off click is normal for pressure switch operation, a pump pressure control switch that buzzes or chatters is sick and needs repair or replacement.
Examples of some key switch chatter or bounce causes are given below. Our full list is in the article just cited above. Schneider, discussing maintenance of their Square-D pressure control switch series offers these explanations and cures for a chattering pressure control switch adapted :. Great site and thorough set of diagnostic resources!
I wasn't able to find a noise similar to what my system is doing on your site, so I figured that you may be able to add it to your library Prior to this set of sounds, I was getting an intermittent chatter, which was resolved by swapping out the contactor and cleaning all electrical contacts. Now I'm getting this noise attached , which was not resolved by changing thermostats Had a Nest, and was suspicious that it may be a software based issue - Installed honeywell rthb.
Seems to be sporadic as to the timing, but I tend to hear it at night - perhaps primarily due to the fact that I'm in the house, and it's quiet. Temperature is cool enough right now to get by with fans while I figure it out and before I break down and pay someone for a diagnosis! Any info you have is helpful. MOV file] sound recording no image [ KB]. I'll look at the video, and post with comments and send you that link for comment. Thank you so much. About remaining chatter comment more after seeing video , it's easy enough to take the thermostat out of the equation: just disconnect it entirely at the appliance-end and jump the two TT wire terminals together at the appliance - that's the same as the thermostat calling for cooling or heating or whatever.
My neighbor is a commercial hvac guy so we're going to climb under the house tonight and see if we can take a look - I'll update you if we get anywhere! We thought that we found the issue in a loose connection at a wire nut - when we unscrewed it, the connected wires were actually broken off and stayed in the nut when we took the cap off. We unscrewed, cleaned, re-stripped, and re-connected all of the connections, but are still getting the issue.
We've got a fan control unit white rodgers if I'm calling it the wrong thing here on order, as a colleague of my neighbor suggested that as the next logical step in the circuit. I may be getting some of this confused since I'm translating from memory, but I figure if you know what you're talking about you can probably make heads and tails of it all. Thanks - I'll keep you posted once we get the fan control unit in. If I have a chance to get a video of the chattering contactor with the lid removed, I'll send it on over.
Thanks for the update. The "safety" controls to which you refer are probably pressure sensors that shut off the compressor if the system pressure indicates malfunction or unsafe conditions. Those controls can also produce a hissing sound if they operate.
Look closely at the circuit board; even a non-E. The bad relay you described can be either a root cause of trouble or it can itself be burned and damaged by something else that is too frequently trying to turn a piece of equipment on and off. Came home from a weekend away to a hot, seized compressor. Hoping for the best and giving it the night to cool down and try a restart in the AM. The low voltage issue we suspected sounds an awful lot like the info you have on hard starts, so it sounds like we may end up a bit pricier than I had hoped.
A working theory is that a relay or other component is chattering because it's trying to switch on and start a motor that just won't behave. There is a tremendous industry selling hard-start capacitors to give recalcitrant motors an extra kick in the seat of the pants.
I am usually suspicions that we're throwing good money after bad. Once a motor has seized at all, even if we get it going again by cooling down, and with some motors, squirting in some oil, I think the damage is already done. Installing a hard-start cap is relatively inexpensive and easy so it's not ridiculous to try that, and it may indeed give some extended life to a failing and expensive part, but I'm just sayin'. No Dice on the restart. Got the compressor, coolant, drier, etc. Fingers crossed this solves the chattering issue as well and that it's not a low voltage problem.
Someone checked voltage, right? That's easy enough to do. Also a check of the current draw when the compressor is trying to start is a powerful diagnostic. Very high amps might be read if a motor is seizing. Also a check of pressures is important.
Thanks for the advice and yeah, we checked voltage on day 2 when my neighbor brought his work toolbox home. I'll make sure to mention the pressure check also! Switched out the compressor, drier, capacitor, and relay on the furnace that we hadn't switched out already it was for the heat and shouldn't have had any impact, but while you're in there Cleaned up some wiring connections, Got it charged back up and we're blowing cold air again! Thanks for all of your help and advice, and I hope this helps someone else down the road!
Congrats; those repair costs sound surprisingly low, especially including the compressor motor. I'll post your discussion. Special Thanks : to Alan Carson, Carson Dunlop Associates, for technical review, comments, questions that improved the content and accuracy of this article. August Good point, G. I'd give a call to the service manager at your service company, discuss the recurrence of this failure, and ask that she send out a senior tech who can track down the underlying issue, such as a failing compressor motor, improper refrigerant charge, failed TEV etc.
Seams like there must be another issue. Need to find replacement for this part. After shutting off the power I inspected the switch and the wiring. Both looked good. Coincidentally I just had a new fan motor installed 2 weeks ago so I thought for sure the issue was related to the new fan motor. The thermostat is old, about 23 years old. I replaced all 3 AA batteries in the old thermostat and to my surprise the outside contact switch quit clicking when the outside unit is running.
In my case this was an easy fix and I got lucky this time. Sounds like a bad fan motor. It also sounds as if you were working on your equipment without turnng the power off -- which could easily shocked or kill you.
My AC stopped working, The fan would not run at all. I have replaced the capacitor and the relay switch. When I first take capacitor out, the relay switch started clicking or chattering noises. I had to unplug the wires to the relay. After replaced with new capacitor, the fan started working, but the noise on the relay never stopped. As a result, the output tube keep showing white frozen ice.
The RC combination absorbs the high-energy oscillations caused by the contact bounce. Similarly, the oscillations created by the arcing are averaged and suppressed by the RC combination. This RC network will also help suppress the arc during the contact break operation and increase the overall life of the relay.
The formulas set forth above are used as a starting point when determining the resistance and capacitance needed for the RC network. As always, the final selection should be evaluated in the application to determine its acceptability.
Contact chatter is extended contact bounce that is not an inherent part of the relay. Contact chatter usually occurs because of either shock or vibration to the relay or an improper control signal to the relay. For the purpose of this discussion, the primary focus is on the control signal to the relay. A control voltage is applied to the coil of the relay in order for the relay to operate. The relay has a minimum voltage that provides proper actuation of the relay contacts.
If the control voltage drops below the specified minimum operating voltage, the relay may chatter. This rapid on and off cycling of the contacts occurs continuously for several seconds, causing excessive heating of the contacts and resulting in severe damage to the relay contacts.
This low-voltage chatter condition occurs due to the insufficient pull of the magnet at low voltages to overcome the spring forces that are needed to operate the relay effectively. A typical force-distance plot of a relay is shown in Fig. The armature spring keeps the contacts open when there is no voltage applied to the coil and opens the contacts when the voltage is removed from the coil. When voltage is applied to the coil, the armature starts to close and the armature spring force increases until the moveable contact touches the stationary contact.
At this point the armature spring force is combined with the contact spring force. This total force increases until the armature is fully seated. When the voltage applied to the relay coil is above the minimum requirement, the pull force of the magnet is greater than the spring force and the relay operates normally. The force of the pull curve is above the force of the springs throughout the full stroke of the relay. At a voltage lower than the specified pick-up voltage, the pull force of the magnet is not strong enough to overcome the spring force of the relay once the contact spring is activated.
At this point, the relay contacts will chatter and remain chattering as long as the low voltage continues. See Fig. One factor that should be considered with regard to contact chatter is the inrush current of the relay coil.
The coil current is higher than the rated current when the relay initially operates. A control voltage is applied to the coil of the relay in order for the relay to operate. The relay has a minimum voltage that provides proper actuation of the relay contacts.
How do you check a relay? Listen for a click when the relay is energized. Check the energized condition of the relay contacts. Use a digital multimeter DMM to test the resistance between each pole of the relay and the corresponding NC and NO contacts for that pole. All NC contacts should read infinite resistance to the corresponding pole. A Dc relay coil has resistance that limits the dc current.
An AC coil relies on its impedance for governing the current. An AC relay will remain contact closed due to mechanical inertia and a little mechanical hysteresis and, the fact that an alternating north and south pole both attract the relay armature. Why does my hid relay buzz? The reason the buzzing occurs even with the ECE's connected directly to the ballasts is that the relay is still receiving the pulse. Putting the ECE's in the path of the pulse and having them receive the pulse before the relay may solve the issue.
Why do contactors buzz? The cause of your "deafening buzzing" could be due to a damaged or missing shading coil. Have you checked that the shading coil is in fact installed, and if so is it in one piece. I have had brand new contactors right out of the box come both without the shading coil, or with a damaged one. Why does a contactor coil burn out? If you supply an AC contactor coil with less than rated voltage you risk the burn out due to the armature not able to fully engage.
Do relays fail open or closed? As you can see, relays most commonly fail in the "stuck open" position where the mechanical switching element fails to close and the relay fails to carry a current.
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