Callback: The Low Pressure Switch That Didn't Make Sense

Comments · 88

• JU

  @JustinTimeHVAC · 3 months ago · pinned

  Before you watch… what would’ve been your diagnosis? 🤔<br><br>✅ 24V in<br>✅ 0V out<br>✅ 0.0Ω across the switch<br><br>Something here didn’t add up. 👇

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• WO

  @woolval52 · 3 months ago

  The use of that fuse in-line was good to see. Instead of just twisting the wires together, you made sure to protect it from any potential overload. I&apos;m not an AC tech, but I can appreciate smart, safe methods. And I really like seeing other AC techs on here giving tips and sharing their experiences. Good group of guys. Watching your videos shows me you earn your pay. People probably assume that since you&apos;re an AC guy there&apos;s no sweating involved! Thanks for posting another video for my entertainment. Have a cold beer... you&apos;ve earned it.

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• BE

  @BernerDad · 3 months ago (edited)

  Hey you’re allowed to get frustrated especially after a long week! But remember, you never gave up! You methodically identified the problem using your knowledge and expertise which benefits the customers! I am sure you are valued and appreciated! Rest up Monday comes quick! 🇨🇦

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• RO

  @RogerGregory-vl4kb · 3 months ago

  You can put a Tee on the low pressure Shrader where you hook your gauges and add a low-pressure switch there.

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• DA

  @davidgearardo1788 · 2 weeks ago

  Man I couldn’t agree more on the pressure switches I’ve never understood the braze in type pressure switch it’s ridiculous

• JA

  @jamesfitzsimmons381 · 3 months ago

  Think maybe someone may have answered it &nbsp;couldn’t see all the meter ranges you were in but I bet it you checked the resistance of the the LPS while you had it jumped out to would see a resistance rising or bouncing up and down. &nbsp; Either way you are one smart guy

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• HI

  @HichamHVAC · 3 months ago

  Good job finding the issue. With that being said, quote the customer the high pressure switch as well since the system going to be open. It’s a job security my friend.

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• JK

  @jkmarshall3553 · 3 months ago

  That sensor is a real head scratcher for sure. &nbsp;But nice work tracking it down!

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• LK

  @LKN-HVAC · 3 months ago

  Hey, at least it was Friday Justin! &nbsp;I have seen a few switches act like what you saw over the years but rarely. This might be the case but wanted you to hook that open lead off of the switch back into the circuit with a clamp on the 24 line with a low scale clamp range of 2 or 10 amp scale meter while monitoring the 24 volt side.<br>Under ohms test (tiny current, no AC), the contacts touch enough to look like 0 Ω.<br><br>Under live 24 VAC, the contact interface is so poor (oxidized/pitted/contaminated) that it behaves like an open or very high resistance.<br><br>With the load wire removed, there’s no downstream path to pull that output terminal up toward 24 V, so it just sits near 0 V relative to C.<br><br>That’s why the jumper works: you’re giving the downstream leg a solid, low‑impedance connection to the 24 V feed that the switch can’t provide anymore.<br><br><br>I feel your frustration with the sweat in switches and there are more than just the 3 to 5X more cost for flared switches. It is nothing more than counting beans to them!<br>The manufacturer’s perspective:<br><br>Schrader = leak risk<br><br>Schrader = more warranty claims (Leaks)<br><br>Schrader = more certification cost (Factory required testing)<br><br>Schrader = more assembly time<br><br>Schrader = more field failures<br><br>A sweat‑in switch is cheaper, simpler, and more reliable for them. So bottom line the owners cost to repair isn&apos;t their concern!<br><br>Wouldn&apos;t it be great if a manufacture designed a system that is deemed the most inexpensive system to maintain because all replaceable parts can be changed at a 1/4 of the labor cost of all other systems so the longer you own that easy to service equipment the more you save over time due to 5 minute parts change even on blower motors. Designed by engineers and the help of HVAC service technicians for quick servicing of all parts! Yeah dream on....but they could do it! <br><br>Go get your M12!<br><br>Have a wonderful weekend!<br><br>Stay safe!

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• ST

  @stevendevilliers471 · 3 months ago

  Same game , different continent. Don&apos;t sweat it brother. Sometimes we all have just had enough and these small things push us over the edge. I take a step back and thank the lord that I have work and the ability to perform my job🎉🎉🎉🎉🎉

• CR

  @cryptogeek3559 · 3 months ago

  Happy Friday.

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• MI

  @mikemc7540 · 3 months ago

  Input impedance of your meter is in megohms but the contactor is in ohms. The switch has enough resistance that it won&apos;t support the contactor load but the continuity mode on the meter will show continuity up to a high resistance. That&apos;s why I kept my simpson analog meter for resistance and continuity checks.

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