Thanks , that was a worthwhile video. I know what they look like and how to check them already, but I still try to learn new techniques…..it would be cool to show the parts close up , for newer guys. But yeah , you're doing a service to the industry with these, good on you , Sir.
My church Rheem heat pump did not come on when I called for ac. I pressed the contactor at the unit and it just clicked. The defrost board was normal and then after I pressed the contactor, the lights blinked. I didnt read what the code equates to before I left. Am I suppose to find 24 volts at the LP and HP. Can I reset the board to see if it will start?
I know this is a beginner forum but I had 2 today low/high on a Trane that would shut off the outdoor unit but not blow the ah fuse. Resistance through switches was 2.4 k ohms. It was intermittent and happen once every 10 hours roughly. I bypassed them. Not a service call you want when units run great while you're there.
My current situation: Split System HVAC compressor and fan do not operate. Indoor unit and thermostat working properly. Capacitor is new. When I depress the plunger on the relay, they both start. There is no 24v to relay coil. Coil has continuity. Pressure switches have continuity. OF1 & OF2 has continuity. What's left? Could the HK32EA007 Board be bad?
Use your electrical meter to diagnose what is blocking the signal between your thermostat and the contactor. If the contactor works and the stat works, it is something in-between.
So, oddly enough, I went to the outside unit to check voltages at the board with my DMM. As I checked power to Common at the T1 C C O connector, the Relay Coil energized and the AC has been running fine ever since. Not sure what happened to make it do that? Thanks for your reply!!!
The Lennox unit I just repaired at my home has a pressure switch with a reset button on it. The outdoor unit would not power on at all. I pushed the button on the High Pressure Switch and the unit started running again. I felt a distinct click when I pushed the button which I did not feel in subsequent pushing.
u repaired ur own unit? Are u a technician? 99% of the time a tripped pressure switch means u got another problem on residential equipment. You should have it looked at by a pro. Make sure everything is clean. A compressor running high pressure means high bills and very soon to be bad compressor
If it went out again after that clean the condenser coil, some gasses are bad in terms of glide so can be affected by mainly heat, but well just say ambient temperature, and the other consideration can be the fan rpm, in some machines there’s a variable speed fan, if it can’t do the full range you’ll get issues, pressure switches do wear out also, but good job, a technician usually would just reset it, and run unit, clean it and see if the call returns.
Depends on what you mean. What's starting and stopping? The fan and the compressor, just compressor, compressor stays on but fan is intermittent? If both constantly turn off and on intermittently then you may have bad contactor or capacitor.
Thank you for a most helpful video. My condenser (Carrier 3 ton 14 SEER) has no low pressure switch in it. It is possible to have one added? If so do you have any pointers as to what to purchase?
@@TECTubefilms We have to find a leak and fix it so we'll be doing the evacuation anyway I just ordered a few things so will have my guy add the switch We are in Bahamas so these things are hard to get hold of. Thank you for you thoughtful reply and excellent video.
@@TECTubefilms You don't need to braze it in. If you don't mind looking like a newb, use one of those t's you put on the service port that turns the port into 2, one for gauges and one for the new pressure switch. Don't do that if you want to look professional though.
i didn't test my switches, but i bypassed them and grounded the contactor the AC still didn't run...could it be the relay board on the unit? I so far changed the main board the capacitor and the contactor...the compressor runs if i push the contactor by hand, I'm running out of things to replace lol
What were the reasons you had to change the board, the capacitor, and the contactor? That is a lot of stuff. What happened that damaged them all at the same time? How did you test each of those to determine they needed to be replaced?
@@TECTubefilms none of those are bad but before i did enough research i had those spare parts on hand so i replaced thinking its the contactor then i said well ill try capacitor. I replaced the board with another board that has a fuse unlike the old one. But after ive done my research and diagnosed none of those were broken...
I have the same problem, but for me, if I press the contactor the AC runs but without cold air. I think there is a leak somewhere and AC is out of R22 (that's why contactor doesn't remain engaged). And since it's R22 I plan to replace the whole unit. It's also over 20 years old.
@@RahulRathi_Multimedia i ran further testing and the low pressure switch is open, i bypassed it and compressor runs but doesnt cool, also r22 so i think im in the same boat because r22 so expensive and hard to find thanks to the overreach of epa
@@RahulRathi_Multimedia If you push the contactor in, it only engages the outdoor unit. To get cold air delivered in the home, you also need the indoor unit's fan to be turned on.
@@thomasguillen5898 You need to determine if the pressure switch is actually bad or if the pressure in the system is getting too high and hence the switch is just doing it's job.
Thanks for the video =). Leaving some feedback here that you might want to consider related to safety: Apparently some AC units have pressure sensors without Schrader valves so removing them without depleting the refrigerant inside can be hazardous. It would be good to mention some disclaimers related to safety.
Why would it be any harder to check voltage vs continuity? Either way, you have to get to both sides of the switch. If there is more than one switch, you have to check each one anyway. Continuity may be more useful, but I don't see it being any easier.
It is personal preference. One of our trainers, Ryan, always uses continuity to test any switches, while many of our other trainers use voltage. In our experience, it seems that those who were trained in HVAC programs at colleges or unions test switches with voltage and those with building automation backgrounds use continuity.
The only disadvantage of testing with voltage is that you need to know what voltage to expect (DC or AC... 24, 120, 240, etc) whereas with continuity you do not need to know anything about the rest of the circuit.
Pressure switches are "normally closed" devices and open when something is not right so in this case the switch will be closed unless the pressure is too low. We are not sure what you are asking when you say "taken off the low side."
@@TECTubefilms He means if you remove the low pressure switch from the system, should it be open or closed. Or in other words, would they normally be open or closed at 1 bar. The answer is no. Low pressure switch is designed specifically to shut down a super low charged system. The worst low charged system is 1 bar, so the switch should be open if taken off the unit.
the ac guy I have said my high pressure switch was bad . but after watching this video I test the switch and I have continuity so it's a good switch or could it be bad?
Without being there to test it ourselves, we do not know why he concluded it was a bad switch. Having continuity doesn't necessarily mean the switch is good. Having continuity, just means the switch is closed. Then the question becomes "was the pressure the moment you tested the switch the correct pressure that it should be closed at?" Also, the switch could be broke in the closed position and hence it always has continuity even when the switch should be open.
Pressure switches rarely go bad. Odds are your HVAC guy determined the system wasn't working properly and then found that the high pressure switch was open. What he may have done is he may have then told you the switch is bad. What he should have done is find out why the switch is open. The reason it would be open would be because of, well... you guessed it... too high pressure in the system. When you checked it later, the pressure in the system had probably subsided so the switch closed back. So in other words, based on this very limited info, my best guess is your HVAC guy is lazy or inexperienced and assumed the pressure switch was lying when in reality it was probably just doing its job. The best course of action, given that is true, would be to find out what's causing the high pressure.
@@TECTubefilms Not sure why you're confused. Sounds a lot like what most HVAC techs would do: Pressure switch open = bad pressure switch. What they should do is: Pressure switch open = why is the pressure switch open?
Good video Question : I have a one and a half ton 220volts split unit AC. After few seconds of turning it on the clamp meter reads 22A then rise to reach 37A for few seconds then it stops and the clamp meter reads zero or 0.1A What could be the problem?
@@TECTubefilms Just to clarify - so testing the switches while they are in the unit cannot tell you if they are bad or not, just that they are open, correct? The other thing you would have to rule out is that your pressure is not high/low. If it is normal pressure, then an open switch would indicate a bad switch, correct?
@@mcgu8114 Yes, if you can measure the pressure at the switch and it is in a normal range compared to the trigger point of the pressure switch but the switch is open anyway, then the switch itself is the issue. That statement holds true for all pressure switches for all fluids.
@TECTubefilms I have a 410 a system and only runs for a minute cuts off and goes into the 5 min delay and does the same thing. High side is 300psi and low side 130 psi the pressure switch trips the unit off and then resets how do I test a pressure switch to know if it's faulty
one way to test the pressure switches is to . 1. to test the high pressure switch just disconnect the fan motor and let the head pressure go high maybe even throw a blanket over the unit to prevent convection cooling. 2. to test the low pressure switch just connect a refrigerant recovery tank to the unit and let the refrigerant out into the tank until the unit shuts off. the recharge the unit. if the unit has the low pressure switch connected as a thread on and there is a valve stem similar to a tire you can remove the switch and the unit should shut off.
Thanks for shooting your Roadstar mod video in a vertical format on your camera even though the bike is horizontal. And because of the unsteady camera work, we were unable to use your video to enhance our own bike and wasted our time watching it. ua-cam.com/video/AXBqv6sY4-w/v-deo.htmlsi=_26Sc2Lli9VbcjjO
Your explanation of why checking continuity over voltage was golden.
Thanks , that was a worthwhile video. I know what they look like and how to check them already, but I still try to learn new techniques…..it would be cool to show the parts close up , for newer guys. But yeah , you're doing a service to the industry with these, good on you , Sir.
Yep. Our camera guy may go back to using 2 cameras... one for the trainer and one for the close up shot of what he is doing.
Thanks that’s what I was looking for
My church Rheem heat pump did not come on when I called for ac. I pressed the contactor at the unit and it just clicked. The defrost board was normal and then after I pressed the contactor, the lights blinked. I didnt read what the code equates to before I left. Am I suppose to find 24 volts at the LP and HP. Can I reset the board to see if it will start?
I know this is a beginner forum but I had 2 today low/high on a Trane that would shut off the outdoor unit but not blow the ah fuse. Resistance through switches was 2.4 k ohms. It was intermittent and happen once every 10 hours roughly. I bypassed them. Not a service call you want when units run great while you're there.
How does one change out a pressure switch?
Thanks!
How I downloaded red sheal refrigeration and air conditione mecanical pdf book please geys tell me if u know
Nice job, very clear and easy to understand
High pressure switch should be close .low pressure switch should be open this is correct ?
thanks nice video
My current situation: Split System HVAC compressor and fan do not operate. Indoor unit and thermostat working properly. Capacitor is new. When I depress the plunger on the relay, they both start. There is no 24v to relay coil. Coil has continuity. Pressure switches have continuity. OF1 & OF2 has continuity. What's left? Could the HK32EA007 Board be bad?
Use your electrical meter to diagnose what is blocking the signal between your thermostat and the contactor. If the contactor works and the stat works, it is something in-between.
So, oddly enough, I went to the outside unit to check voltages at the board with my DMM. As I checked power to Common at the T1 C C O connector, the Relay Coil energized and the AC has been running fine ever since. Not sure what happened to make it do that? Thanks for your reply!!!
Any luck getting this resolved? It sounds very similar if not exactly the same as to what I’m experiencing.
The Lennox unit I just repaired at my home has a pressure switch with a reset button on it. The outdoor unit would not power on at all. I pushed the button on the High Pressure Switch and the unit started running again. I felt a distinct click when I pushed the button which I did not feel in subsequent pushing.
u repaired ur own unit? Are u a technician? 99% of the time a tripped pressure switch means u got another problem on residential equipment. You should have it looked at by a pro. Make sure everything is clean. A compressor running high pressure means high bills and very soon to be bad compressor
@@hvacdr
It was the result of having switched the AC on and off and then on again too quickly. It's an old unit. But it still works.
If it went out again after that clean the condenser coil, some gasses are bad in terms of glide so can be affected by mainly heat, but well just say ambient temperature, and the other consideration can be the fan rpm, in some machines there’s a variable speed fan, if it can’t do the full range you’ll get issues, pressure switches do wear out also, but good job, a technician usually would just reset it, and run unit, clean it and see if the call returns.
Distant click was the contactor.
Thanks for the video. Will the system start and then cut out after a few seconds if the refrigerant is low?
Depends on what you mean. What's starting and stopping? The fan and the compressor, just compressor, compressor stays on but fan is intermittent? If both constantly turn off and on intermittently then you may have bad contactor or capacitor.
Thank you for a most helpful video. My condenser (Carrier 3 ton 14 SEER) has no low pressure switch in it. It is possible to have one added? If so do you have any pointers as to what to purchase?
Yes it can be added. But it would not be worth the cost to evacuate the system and pipe it in.
@@TECTubefilms We have to find a leak and fix it so we'll be doing the evacuation anyway I just ordered a few things so will have my guy add the switch We are in Bahamas so these things are hard to get hold of. Thank you for you thoughtful reply and excellent video.
@@TECTubefilms You don't need to braze it in. If you don't mind looking like a newb, use one of those t's you put on the service port that turns the port into 2, one for gauges and one for the new pressure switch. Don't do that if you want to look professional though.
Can’t see shit
i didn't test my switches, but i bypassed them and grounded the contactor the AC still didn't run...could it be the relay board on the unit? I so far changed the main board the capacitor and the contactor...the compressor runs if i push the contactor by hand, I'm running out of things to replace lol
What were the reasons you had to change the board, the capacitor, and the contactor? That is a lot of stuff. What happened that damaged them all at the same time? How did you test each of those to determine they needed to be replaced?
@@TECTubefilms none of those are bad but before i did enough research i had those spare parts on hand so i replaced thinking its the contactor then i said well ill try capacitor. I replaced the board with another board that has a fuse unlike the old one. But after ive done my research and diagnosed none of those were broken...
I have the same problem, but for me, if I press the contactor the AC runs but without cold air. I think there is a leak somewhere and AC is out of R22 (that's why contactor doesn't remain engaged). And since it's R22 I plan to replace the whole unit. It's also over 20 years old.
@@RahulRathi_Multimedia i ran further testing and the low pressure switch is open, i bypassed it and compressor runs but doesnt cool, also r22 so i think im in the same boat because r22 so expensive and hard to find thanks to the overreach of epa
@@RahulRathi_Multimedia If you push the contactor in, it only engages the outdoor unit. To get cold air delivered in the home, you also need the indoor unit's fan to be turned on.
Will a bad high pressure switch .. stop the condensing unit from cycling off when set temperature reached? Thanks...
No. Once the thermostat stops calling for cooling, the unit will shut-off regardless of the pressure switch.
@@TECTubefilms Thanks a lot for your response I was having this issue with my ac was looking for a solution ....
@@thomasguillen5898 You need to determine if the pressure switch is actually bad or if the pressure in the system is getting too high and hence the switch is just doing it's job.
That 2nd low pressure switch Cannot Be Good because it read Closed and it’s not even hooked to the System Sensing Ref. Flow.??
It's probably a high pressure one.
Thanks for the video =). Leaving some feedback here that you might want to consider related to safety: Apparently some AC units have pressure sensors without Schrader valves so removing them without depleting the refrigerant inside can be hazardous. It would be good to mention some disclaimers related to safety.
Yes sir👍
Why would it be any harder to check voltage vs continuity? Either way, you have to get to both sides of the switch. If there is more than one switch, you have to check each one anyway. Continuity may be more useful, but I don't see it being any easier.
It is personal preference. One of our trainers, Ryan, always uses continuity to test any switches, while many of our other trainers use voltage. In our experience, it seems that those who were trained in HVAC programs at colleges or unions test switches with voltage and those with building automation backgrounds use continuity.
The only disadvantage of testing with voltage is that you need to know what voltage to expect (DC or AC... 24, 120, 240, etc) whereas with continuity you do not need to know anything about the rest of the circuit.
Will my low pressure switch test closed when taken off the low side?
Pressure switches are "normally closed" devices and open when something is not right so in this case the switch will be closed unless the pressure is too low. We are not sure what you are asking when you say "taken off the low side."
@@TECTubefilms He means if you remove the low pressure switch from the system, should it be open or closed. Or in other words, would they normally be open or closed at 1 bar. The answer is no. Low pressure switch is designed specifically to shut down a super low charged system. The worst low charged system is 1 bar, so the switch should be open if taken off the unit.
the ac guy I have said my high pressure switch was bad . but after watching this video I test the switch and I have continuity so it's a good switch or could it be bad?
We are a little confused. If he tested the switch and concluded it was bad, why did he not replace it?
Without being there to test it ourselves, we do not know why he concluded it was a bad switch. Having continuity doesn't necessarily mean the switch is good. Having continuity, just means the switch is closed. Then the question becomes "was the pressure the moment you tested the switch the correct pressure that it should be closed at?" Also, the switch could be broke in the closed position and hence it always has continuity even when the switch should be open.
@@TECTubefilms is
Pressure switches rarely go bad. Odds are your HVAC guy determined the system wasn't working properly and then found that the high pressure switch was open. What he may have done is he may have then told you the switch is bad. What he should have done is find out why the switch is open. The reason it would be open would be because of, well... you guessed it... too high pressure in the system. When you checked it later, the pressure in the system had probably subsided so the switch closed back. So in other words, based on this very limited info, my best guess is your HVAC guy is lazy or inexperienced and assumed the pressure switch was lying when in reality it was probably just doing its job. The best course of action, given that is true, would be to find out what's causing the high pressure.
@@TECTubefilms Not sure why you're confused. Sounds a lot like what most HVAC techs would do: Pressure switch open = bad pressure switch. What they should do is: Pressure switch open = why is the pressure switch open?
Good video
Question : I have a one and a half ton 220volts split unit AC. After few seconds of turning it on the clamp meter reads 22A then rise to reach 37A for few seconds then it stops and the clamp meter reads zero or 0.1A What could be the problem?
Suhaila Saba compressor
@@Isaiah626_ Thank you for your answer
I bought 5 high pressure they all had 6 k ohms not close even put on high pressure air not change resistances
When your unit is off are both high and low pressure switches supposed to be off ? My unit is short cycling
The pressure switches will be normally closed and when the refrigerant pressure is too high or too low, they will open and turn the unit off.
@@TECTubefilms Just to clarify - so testing the switches while they are in the unit cannot tell you if they are bad or not, just that they are open, correct? The other thing you would have to rule out is that your pressure is not high/low. If it is normal pressure, then an open switch would indicate a bad switch, correct?
@@mcgu8114 Yes, if you can measure the pressure at the switch and it is in a normal range compared to the trigger point of the pressure switch but the switch is open anyway, then the switch itself is the issue. That statement holds true for all pressure switches for all fluids.
@TECTubefilms I have a 410 a system and only runs for a minute cuts off and goes into the 5 min delay and does the same thing. High side is 300psi and low side 130 psi the pressure switch trips the unit off and then resets how do I test a pressure switch to know if it's faulty
@@jasonmontroy9182he literally just told you???
This would've been a great video, but the unit is 10 miles away and couldn't see anything.
Cant see anything your explaining.its best to have your cameraman zoom in.
I agree with you!
Are the switches in parallel or series
safety switches should be wired in series.
When you try so hard you forgot the goal
Why does he hold his hands so far out in front of him? It's killing me, i literally can't even
Smh
does an LPS open usually break the 24v common?
Yes on contact
And high pressure switch it’s wired in series
Yes
one way to test the pressure switches is to .
1. to test the high pressure switch just disconnect the fan motor and let the head pressure go high maybe even throw a blanket over the unit to prevent convection cooling.
2. to test the low pressure switch just connect a refrigerant recovery tank to the unit and let the refrigerant out into the tank until the unit shuts off.
the recharge the unit.
if the unit has the low pressure switch connected as a thread on and there is a valve stem similar to a tire you can remove the switch and the unit should shut off.
Worthless....you showed nothing about where to actually locate and test....everyone knows how to check continuty...
What additional specific information would you like to have seen related to pressure switches? We are looking for future video topics.
@@TECTubefilms how to replace it
@@TECTubefilms How to find the wiring diagram, lol.
Thanks for not showing close up of pressure switchs.trying to get my ac working and just wasted more time
Thanks for shooting your Roadstar mod video in a vertical format on your camera even though the bike is horizontal. And because of the unsteady camera work, we were unable to use your video to enhance our own bike and wasted our time watching it. ua-cam.com/video/AXBqv6sY4-w/v-deo.htmlsi=_26Sc2Lli9VbcjjO