So we've got a walk-in freezer, that's not working properly. The complaint is, is that they're getting frost all over the walls of the unit? Upon arrival, I did not see any ice on the walls. However, I did notice that the door hinges. Enclosure are not closing the door properly they're currently doing a product rearrangement in the freezer, so I'm going to come up on the roof and check out the equipment.

It's a heat crab condensing unit, so we've got a head pressure. Control valve sightglass apparently looks clear. We'll go ahead and gage up and check everything out. So the first thing I noticed when I put these gauges on is that my superheat was a little bit high now granted.

This is the superheat out the compressor currently at 46 degrees, but I'm gon na go ahead and click over to the evaporator, superheat and you're gon na see that's running actually kind of high too. So here we go and we're at 20 degrees, evaporator superheat. We want to be a lot closer to 8 degrees on this particular box, so I went ahead and tried to adjust on the TX v and no dice. It does not drop the superheat there's something wrong with the TX v.

So my walk-in freezer has two high evaporator superheat and not expansion valve has been adjusted as far as it'll go he's got a number three cartridge in it or 404, so we're gon na recommend replacing that txp. So here's what we got: 12,000 BTU evaporator coil 14,000 BTU condenser coil a number 3 cartridge in the spoilin q body expansion valve. If you go to 404 a refrigerant. The number 3 is a one ton valve and if you go to heat craft and look what they call four 12,000 BTU at a negative 20 evaporator, they call for a one and a half ton.

So it looks like someone went a little small on the TXV. So we're gon na need to up the size. So if we go up to the number four valve or number four cartridge for 404 a, we would get a one and a half ton or that's what we would be required. And if we go again to right here for twelve thousand BTUs, it's asking for a one and a half ton.

So that would explain why our superheat is way too high and we've got the valve adjusted and we can't get it any lower. One of the cool things about digital gauges: you can do little experiments and see a little bit more into the system. So here I'm going to show you guys the operation of the head pressure control valve or the head master. So I've got my probes hooked up to all different parts of the head master, basically all three sides of it.

So I can measure the discharge line: temp the liquid line temp and the liquid drain. So here's an example of a system where a head master is not bypassing. Okay, I'm gon na click on the high pressure. We've got a liquid line, temperature of 75 degrees.

We have a discharge line, temperature of 118 degrees at the head master and we have a liquid drain of 75 degrees. That's all at the head master right now so here in a second we're gon na switch over to a bypassing head master and what I did was I actually wet the condenser to get it to simulate a bypassing headmaster and not really simulate, but it made it Happen so here we go, the condenser is wet. I have a 71 degree liquid line temperature, a hundred and thirty six degree discharge line temperature and a 55 degree liquid drain coming out the bottom of the condenser. So you can actually see the head master, bypassing just thought that was cool.

It's a recap. Service call walk-in freezer, having frost on the walls didn't find any when I got here found that the door was not shutting properly and then also found that we had an expansion valve that was originally installed. That was too small. You.