We have a service call on a walk-in cooler, that's at 55 degrees, evaporator fan motors are running and at this time I don't see any ice. These are our walk-in condensers. We've got a freezer and a cooler I'm assuming that one's the freezer, because that's the one. That's running but well jump in here and figure it out little tour, real, quick everything looks good all right, so get the electrical opened up.

The first thing we're gon na do is check three-phase power. Coming in, let's see what we got here, go away. Go away! Go away our contactors not pulled in, but we know we have three-phase power coming in the next thing. I'm gon na do is jump over here to the time clock and check one two neutral go away.

I'm gon na check. I should say one to end: we're gon na check three to end to make sure home and then we're gon na check for two end three to end is our default or get so Florida and that's our refrigeration circuit, so we're in refrigeration mode right now. Okay, we're gon na go ahead and check our low pressure control, see if we've got an open circuit and we do so. Our low pressure control is open right now, so we are gon na have to get some service gauges on this and see why we have an open, low pressure control.

So that's interesting. We have equalized pressures in the system. There's plenty of pressure on the low side, pressure control, there's Oakland I'll have to dig into this a little bit more there's something interesting going on here, but temporarily I jumped off a little pressure switch and watching the box run this under a heavy heavy load. So we're gon na let it run for a little bit.

Obviously gon na need to change out that low pressure. So it's kind of strange, though okay, so my pressure control is right. There, that's the capillary and there's no way to shut off the pressure. So what I did was I clip the tube.

This is um, mind you. This is the low pressure control and I pinched it shut because it's just a minor amount. So now we're gon na pump the system down. So I've gone to the receiver valve and I've bunch seated it.

Okay and I've got the new pressure control set in there and wired in, but it's obviously not connected yet because I've got to get the connection on the other port that I've got thin shock. So what we're gon na do? We've got power, turned back on we're gon na, go ahead and jump out this pressure control by using the little spot right here and now it's running and we're gon na pump the system down to about 15 10, psi 10 to 15 psi and then I'll. Just change that pressure control, while there's you know 10 psi of pressure, it'll be no big deal, so we're just letting it pump down right now. We're at 14 well yeah, chill right there and mind you.

It's probably gon na rise a little bit. So the whole point is: is we want pressure coming out the whole time, I'm changing it? That way, we don't ever run the system out of gas. So now I'm just gon na get in there with a couple wrenches and twist that thing off okay, so I've got it replaced now. What I did was I just made that finger tight, then loosened it and put my finger on it.

Put some nylon on the threads he's the nylon glue, it's good stuff, put some dialogue on the threads and also oiled the back side of the flare with nylon too, and then just you know, tighten everything up. I was able to do it without losing the pressure in the system. I mean, if you know, pissed out for a second. That was it, so that's the easy change out and then we'll go ahead and open up the receiver and let the gas flow back through now.

We're able to do this without changing the dryer or having to pull a vacuum, because the system was never completely out of pressure. Another tip is on these receivers or any of these service valves that have packings. So this one has a packing nut. It's got two flat sides to put my wrench on it.

You always want to loosen and tighten those as you're doing the valve, so you notice something this one's actually going to start leaking when I loosen it. Okay, you're gon na make this valve last longer. If you loosen the packing before you open a closed valve, okay, so now don't know if you guys hear that, but it's kind of hissing gas out a little bit. That's how it's going to be okay! So now we're going to open up the system, mind you we're still in a positive pressure about 15 psi.

So now we're going to open up system. So it's open now and it's running so we're gon na test the pressure control settings. Now you can never trust the numbers on the controls. You always need to manually, set them, meaning you need to see where it cuts in and cuts out at, because those numbers can be skewed a little bit so we're gon na pump it down one more time.

We're gon na check to see what the pressure control turns off at and then what it turns on at to verify that we have it set what we wanted. Okay, so we're just going to watch it pump down and then I'm gon na crack the valve and watch it turn back on just to make sure we're good and we're getting ready to shut off right now should be around five or six okay. So it looks like it's cutting out of 15 25. Oh no! That's about right, yeah! So it's 25 yeah! So we'll see! Okay! So now we're gon na bring it back on and just just crack it just a little bit and see where it turns back on.

Okay, my differential isn't enough there. I need more of a differential, we're going to adjust the pressure control accordingly and then repeat to make sure I have a set where I want it on this system. I want it to cut out at about five and then cut in 25, 30 ish somewhere in there. It's just a regular pump down yeah we're going to test it again for cutout about any time.

Okay, I think it's cutting out about two psi. That's okay! A little low but barely crack it and see where it turns on that yeah 30-ish. Okay, that's close enough, but, like I said you can never really trust those, because, according to this, it cuts in at 30 and cuts out at five so and it's actually cutting out at what and in at like 25 inch or 30s or something. So you just got ta always double-check.

The setting this one was a service call on a walking cooler. The unit had a bad low pressure control. It wasn't a really difficult call. Okay.

It was a little strange, though, that the pressure control failed in the way that it did. Basically, the pressure control thought the system was completely out of gas when it wasn't. Okay, so to verify my diagnosis, I went ahead and jumped out the low pressure control and then verified that everything else in the system was working properly and it was so. The system itself was really high in temperature, so I left the pressure control jumped out.

While I went and picked up the parts it took me about an hour or so to go, get the pressure control, so that was good because I was able to see the Box come down in temperature by the time I had gotten back. Okay, another thing was: is I used a shortcut and sometimes we tend to take shortcuts and to try to make our job faster and quicker, I'm okay with shortcuts, as long as they work okay, when they don't work, that's when they start to become problematic. So you always have to be prepared and know what could go wrong so that way, you're ready for it. Okay, so I was able to pump this system down at the liquid line receiver to about 6 psi.

So basically, I still had 6 psi of positive pressure. In the low side - and I was able to change that pressure, control was just a quarter-inch flare fitting. I was able to twist that off and get the new one on before the system ran out of gas. Ok.

By doing that, I saved myself from having to change the liquid line, filter dryer and from having to pull a vacuum on the system. Okay, now again I had everything ready with me. I had already installed the low pressure control the new one, and it was just basically ready to be connected. I had my wrenches that I needed.

I had mine ilog that I needed. I had everything there just in case I ran into a problem. That's a very important thing to understand: ok, there's times that you can do this, there's times that you can't okay, so you always have to be ready. Ok and don't don't just assume, it's gon na be quick and easy, because when you assume that's when it bites you in the butt so change the low pressure control, the system was working.

Great everything else was cool, it had a sightglass. The refrigerant pressures were where they needed to be. The temperature controller was cycling where it was supposed to be. Everything else was great.

Okay, so that's it. I want to say thank you very much like I have in the last videos. I really appreciate you guys watching my videos. I do enjoy the feedback.

I've been getting lots of emails from you guys, keep them coming. Ok, lots of questions. If I haven't gotten back to you yet I will okay, it's just taking some time to get through it. There's a bunch of emails, but I'm getting through them and I think I've answered majority of them.

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