This was a service call on a walk in freezer temping at 20 degrees I found that the systems temperature controller was adjusted too high. I corrected the setting and watched the unit come down to temp.
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So today's service call is a walk-in freezer temping in the 20s and they're saying their ice cream is all soft. They say they noticed it. Yesterday, here's my unit, that's the back of my evaporator coil. So we do not have an ice tub condition.
I've got a thermometer in here right now to monitor box temp and I'm gon na go ahead and go on to the roof and check the system out my little thermometer right. There is 23 degrees, so it seems about 2-1 in the 20s. We come up here to the ice cream. Oh yeah, that ice cream is from Hill.
An ice-cream needs to be in a negative 10 to be firm and hard. So I'm up on the roof. Here's our equipment, visually we've got a clear sight. Glass condenser fan motors are running, the condenser is clean and it's looking okay flat.
I will say that a for a walk-in freezer I stood see some frost and we're not. You know usually you'll see this being frosting and fill up a lot colder, so we're gon na go ahead and gauge that, because I'd be able to knead and see what's going on within the system, all right, so this unit is actually cycling off. I have a feeling that it's cycling off on temperature because it just turned on when I had satisfied and then it just turned back on. Let's look at our box 10.
Our box temp is 24 degrees, so I think we need to be looking downstairs because a refrigerant pressures horrible. It's actually pumping down right now, that's kind of strange, so yeah I'm going to jump onto the route or downstairs and look at that temperature controller and see. What's going on with that, it's interesting, so this thing is satisfied and we're currently at 24 degrees in the box yeah. So we've got a temperature controller problem.
Well, it was set for 25 degrees. So that's a problem yeah. So now I need to make a decision see that I don't like what they found these controls on the okay. So I'm assuming that you guys caught what happened there.
We had a service call on a walk-in freezer that wasn't working. The complaint was that it was maintaining 25 degrees. So when I went onto the roof I found that the unit was cycling on and off normally okay, so it was pumping down and then eventually turning back on. So what I ended up finding was that the evaporators temperature controller had vibrated itself up to 25 degrees.
It's a very common thing on those evaporator coils, where they mount the control on the coil itself in the beginning. They won't do that, but after some time the controls, the little dial, starts to get a little weak and it'll just be very sensitive to vibration, and it just naturally happens in this instance. I brought that to the customers attention and asked them what they wanted to do and they wanted to go ahead and wait. They did not want me to change the control because we're kind of working on a bigger picture here and they want to start replacing that equipment actually so for now they just wanted me to go ahead and adjust it down and then I'm submitting some quotes to Go ahead and upgrade that equipment for them they've already done their walk-in cooler and they just like to be proactive and want to go ahead and do the walk-in freezer because they just don't want to run into more problems next summer. So with that being said, I just kind of want to go over a little bit real, quick okay, so the system was pumping down. What that means was that the temperature controller was shutting down the liquid line solenoid valve and the refrigerant flow was being stopped at the liquid line, solenoid valve okay, so coming out of the receiver, we have a liquid line running downstairs and right before the metering device. The expansion valve there's a Silla note valve okay, that valve regulates the refrigerant flow: it's either on or off, and it's controlled by the temperature controller. So if that valve is open, then the refrigerant flows through the TX v through the evaporator coil, comes out of the evaporator coil now on the suction line and goes back up to the compressor gets pumped through the compressor out of the discharge line runs through your Condenser comes out of the condenser; it turns into a liquid in the condenser, then runs down to the metering device or expansion valve and then starts the cycle all over again.
Okay, it's important to remember that at the condenser we reject the heat of the refrigerant in the evaporator we absorb the heat of the space. Okay, so we've got the nice air running over the evaporator coil. It's pulling the heat out of the air, absorbing it into the refrigerant pumping it back upstairs, then changing the state of the refrigerant as it pumps through the compressor. Actually, I should say it changes the state once it comes out of the condenser, but pumps from the compressor into the condenser then changes the refrigerant back into a liquid then starts the process over and over and over again until the box temperature gets satisfied.
So, in our case, the box temperature was satisfying too early. We were hoping for a negative 10 degree, space, temperature or box temperature inside that walk-in freezer and we were maintaining a positive 25 degrees. So therefore, we had nice milky ice cream, which is not what the customer wanted. Okay, so went ahead and repaired that and the system is working good and, as far as I say, repair, I simply just turned the control down to negative 10 and watch the Box.
Come down and everything was good, all right guys. Hopefully you learned something. Let me know if you guys have any feedback, send me an email. All my information is in the show notes in the video and we'll see you guys on the next one.
Okay.
Nice, clear explanation of the cycle and what "pumping down" means.
Maybe they wanted ice cream smoothies.
That was a quick one and I liked how you explained the operation. For a newbie that is terrific, got to pound in the theory of operations. If you have that you can theoretically find any problem right? Thx for the great videos.
A wad of chewing gum holding the dial seems a lot cheaper than a new freezer to me. I recommend Big Red…delicious as well as functional. Service area Ottawa??
Good evening from Jakarta Indonesia, would you please share everything about Air blast freezer..what is subcooler and how how does it work on 2 stage compresor..thank you so much.
You’d think they would be electronic controls these days
Let's say that they wanted to just replace the temperature control, would it be a good idea to mount the new control box to the wall behind the evaporator to keep the thing from vibrating itself to the wrong temp again over time?
Have used silicone to lock the thermostat but you could replace it
Great explanation of how the refrigerant pulls heat out of the box and discharges it on the roof. Great video.
Can you show me when you have time the whole walking freezer wiring ,thank you very much for your videos,i like it all.
Another good one 👌
Thank you very much every video is a learning for me thank you and god bless
What did you use to check the pressures? I like how you could use your tablet with them. Service area Barrhaven??
Farid from UK.Thank you very much
What is the best refrigeration book? I missed it in the live chat.
They should have checked the temp controller
Employees screwing with the dial or vibration,set it, when temp is reached then fill the slot with a bead of silicone to keep set
Easiest $300 service call ever
Now it's San Samonella soft ice… yummy!!
No drop of securing paint available in the US to keep the thermostat adjusted right?
Had that I've been to a walk-in freezer. I drilled a hole in the temperature dial and use wire to fasten it solid, no more troubles.
I'll bet you one of the staff adjusted it, because they were salty about something, I've seen it before when I worked at a Tim Horton's, guy was written up for swearing in front of customers, being a right dick, he gotten written up and almost fired, the same morning the freezer which is supposed to be -20c was 10c no actual proof but the dial doesn't move easily Service area Orleans??
Hi man good work
Awesomeness.. Great why on describing the service call and breaking it down for people to understand and helps a lot of new Techs out in the field.
Haha. Man, im at a hospital and thats so common there. The kitchen aid would change the stpt bc of it being so cold in a freezer and complain the next day about it.
Can I ask if not too much trouble, what brand/model is your little blue yellow fold out thermometer with stick probe? Thanks
Hey Chris I had a question after watching your podcast on refrigeration controls you were talking about TDs and I was always taught coming up this rule of thumb what’s ur take on this , fan forced evaps 15 degree td, gravity coil 20 degrees and cold plates 25 degreee td
I have a question I hope you have the time to answer. I had a call on a under counter refrigerator where the temperature would get up to 44 degrees then slowly come down to 38 degrees then go back up to 44 or 45 customer said it does not happen to often. I put my gauges on, my low side was at 45-50 my high was 250-300 psi. Evaporator looked ok no ice build up. its like an intermittent problem I wanted to replace thermostat cause I felt that was the issue but it was normal fridge temp which was 39 degrees n defrost clock look ok. My question is did you ever ran in to something like that? If so what was your solution? I'm 2 months into this trade I'm still learning the company I work for just threw me to the wolves. I had this call earlier today n I ordered a thermostat cause I feel that what it was, would love your opinion if you have time thanks.
I bet They got a truck in and they were putting the product away and they turned the thermostat up while they were in there and forgot to turn it back down. Hence why they didn’t want to replace it because they knew they forgot maybe? Just a theory..
Nice tip 👍👍👍👍👍
You are one of the best technicians I’ve ever seen. I’m 20 yrs old and I interested to learn this job. I want to tell you that your videos are great I will learn a lot with your videos. Thank you so much.
Nice video! I usually put some silicone on the temp control dial. I helps it from moving again.
tx Chris
I've noticed from experience if you heat the oil to 365 degrees then the potato chips don't get burnt. Then season them with sea salt for a great taste.
Install a Ranco ETC. problem solved. No more walking from vibration. It either works or doesn’t. The Emerson style ETC are also very neat because you can power steal if you are unable to pull another wire. Are you in Kanata ?
Nice find your experience shows through your work.
Hey I have enjoyed your videos I would like to contact you I’ve got some questions about a cooler I’m having trouble with thanks
Nice explanation about pump down, give me more clear pictures.
Maybe 5 times in a year I had to replace thermostat at walk in cooler and walk in freezer. The manager gets panic when they see the temperature is above the 41 degree ( walk in cooler) they will fiddle the knob also at the walk in freezer they will freak out when they see 20 degree ( defrost is normal) I ended up explaining how work like that. But they keep freak out anyways I became used to emergency call like that. Thank you for making video !
Very common for Chili's to make a call like that. They seem to cycle out equipment after 8 years
Good video Chris. What are your thoughts on the Measure quick app? And do you think Jim will release a refrigeration app? Are you in Nepean ?
So when the solenoid shuts , a pressure controller will shut the condensing unit off from going into a vacuum?
Keep them coming
I wish i could get a easy one too? Service area Kanata??
I would have never thought it'd be the thermostat vibrating itself up , I would have been a d$ck about it and thought someone had messed with it !
Dude, thanks for the tip, that's awesome to learn stuff like that!
👍👍
Part # on fieldpiece probes & would you recommend for range? Are you in Orleans ?
Two new words I have learned on my HVAC journey. Endothermic and Exothermic.
Good video Chris Are you in Ottawa ?
Thanks for the video Really enjoy 😊 the Refrigeration Videos
Work