Walk-In-Freezer Condensate Drain Questions

[SandShark]

I have a walk-in-freezer that, whenever it went into defrost, condensate water was dripping from the drain onto the floor. The drain runs outside and I knew I had big problems because no water was coming out of the drain.

I pulled the insulation off the drain line and found two gaping splits in the copper tubing. Not only that, whoever fabricated the drain, field fabricated a trap from copper tubing and elbows. The trap was about 3" deep. Also, the braided pipe heat cable was shorted out. Further investigation revealed the leads from the cable ran over the top of the drain pan, over the drain pan heaters and finally to the evaporator coil terminal board. One lead was connected to "N" and one lead was connected to "3" on the evaporator coil terminal board which meant, even if the heat cable wasn't shorted out, it would be energized only when the system went into defrost.

So, to solve the issue once and for all, I plan on re-piping the drain and doing away with the trap. I plan on replacing the drain line heat cable with a 15' 120V heat cable, wrapping and securing the heat cable around the copper drain line, insulating with 1" wall tubing insulation, installing a dedicated 120V GFCI receptacle behind the evaporator coil and plugging the heat cable into it.

I asked our staff electrician what he thought and he said he had never heard of installing a receptacle inside a walk-in-freezer for a drain line heat cable. I told him I had seen it done this way many times. Is this what you would do in this situation? In not, what do you suggest I do? Thanks.

[smilies]

Yes, I see it done. It then gets replaced with a commercial grade 20a device. The sparky showed me the code where it was acceptable. Mostly, it just gets wired in hot off of coil power.
Oh, the trap...you're gonna want to keep it, just outside the box, above freezing.

[ryan1088]

Sounds like you are on the right track. I do not have any freezers with receptacles in the freezer itself. We do have a few that the outlet is outside near where the line comes out though. I will usually land one wire on one of your incoming power terminals and the other to ground. I've had a lot of trouble with it only being on during defrost.

[jackintheboxtec]

I would just wire it directly to the junction box no plug. Is the trap on the out side of the walk-in or in side? The trap needs to be out side to prevent air being sucked in and causing icing problems.

[SandShark]

Yes, I see it done. It then gets replaced with a commercial grade 20a device. The sparky showed me the code where it was acceptable. Mostly, it just gets wired in hot off of coil power.
Oh, the trap...you're gonna want to keep it, just outside the box, above freezing.

The evaporator coil is 240V, fed by one hot leg from "N" on the defrost clock. "N" on the defrost clock is one side of line at the condensing unit. The other side of line comes from either "3" for the defrost heaters or "4" for the fans. There is no other non-switched 240V circuit going to the evaporator coil. That's why I think there were issues in the first place because the existing drain heater was being fed by the switched circuit feeding the defrost heaters. Therefore, the drain heater was only energized during defrost. I don't want to do it that way again.

I do agree with installing a trap in the drain outside the freezer, though.

Sounds like you are on the right track. I do not have any freezers with receptacles in the freezer itself. We do have a few that the outlet is outside near where the line comes out though. I will usually land one wire on one of your incoming power terminals and the other to ground. I've had a lot of trouble with it only being on during defrost.

There is no ground at the evaporator coil and, besides that, even if there was one, I don't think NEC allows using ground as neutral. It's no big deal running a dedicated circuit for the drain heater. There's a breaker panel right outside the freezer.

I would just wire it directly to the junction box no plug. Is the trap on the out side of the walk-in or in side? The trap needs to be out side to prevent air being sucked in and causing icing problems.

Yeah, doing that is an option. Thanks for the suggestion. Definitely installing a trap outside the freezer, too.

[jackintheboxtec]

They make those heaters 240V also.

[VTP99]

Why not wire it to the fans ? It would be on a lot longer and the pipe would be well heated during the defrost period. If you use a 120v cable where is the neutral coming from ?

[SandShark]

Why not wire it to the fans ? It would be on a lot longer and the pipe would be well heated during the defrost period. If you use a 120v cable where is the neutral coming from ?

That's how it was wired before. Besides, if I were to wire the new heater the way it was done before and the way you're suggesting I do it, the leads of the heat cable aren't long enough to get back to the evaporator coil terminal board. I would have to splice onto the leads and the wires would be exposed on the backside of the evaporator coil, which I don't believe is code. Whoever installed the heat cable before, ran the leads over the drain pan, under the evaporator coil and across the drain pan heaters to the terminal board because the leads weren't long enough to run them on the backside of the evaporator into the coil where the terminal board is located. In other words, it was a jack-leg installation.

As I stated, I plan on running a dedicated circuit from the breaker panel right outside the freezer to a 120V GFCI receptacle behind the evaporator coil. None of you guys have seen receptacles for heat cables inside walk-in-freezers before?

[jackintheboxtec]

Yes I've seen it done that way before but its better to wire it directly. With it being plugged in you run the risk of it getting unplugged then your redoing the pipe again.

[VTP99]

You said it went to #3 and I'm saying move it to # 4
Also if you have to splice just use butt connectors with heat shrink tubing.

[crymtide]

Since we have so many answers I'll add mine. The cheapest fastest most effective method is a heater designed to go inside the drain pipe (available at a refrigeration supply store). You wire it to be on continuously and there is no need for insulation on the drain line. These heaters are braided metal on the outside and feed in to the drain line right at the start in the drain pan with the wiring going to the terminal block where the fans and defrost coils land. On a 208/230 volt system you use the available 208/ 230volt heater or you can get one that is voltage specific 208 vac or 240 vac and land on the incoming terminals supplying voltage to the terminal strips. You'll find only one leg on the fans/heaters is switched on/off by the defrost timer, and choosing the correct terminals will get you power all the time even if you end up jumping to a separate unused terminal to supply your power during fan/heater switching. The braided heaters are available in multiple lengths but aren't designed to go through bends other than the one or two close to the pan so this doesn't work if your running around the walls of the freezer before you exit the freezer wall, but work very well for drains that after 2 or so bends head through the back or side wall.

[prorefco]

I have always prefered Frostex heat tape for freezers. It's self-regulating and since it's not a series heater, it won't burn out even if wrapped over itself. In some cases, I have even ran it through the drain line. It's available in 120 and 240 volt and you cut it to the length you need. I don't think I have ever had one fail on me.

As far as an outlet inside the box, or one dedicated to the drain line heater, I have seen this on rare occasions. It's fine but it's more costly than you need and you always stand the risk of it getting unplugged.

[76olds]

I've seen outlets inside the freezer for the drain line heater.

Powered from the light circuit.

Convenient place to plug in the light when your working in the freezer.

[SandShark]

Since we have so many answers I'll add mine. The cheapest fastest most effective method is a heater designed to go inside the drain pipe (available at a refrigeration supply store). You wire it to be on continuously and there is no need for insulation on the drain line. These heaters are braided metal on the outside and feed in to the drain line right at the start in the drain pan with the wiring going to the terminal block where the fans and defrost coils land. On a 208/230 volt system you use the available 208/ 230volt heater or you can get one that is voltage specific 208 vac or 240 vac and land on the incoming terminals supplying voltage to the terminal strips. You'll find only one leg on the fans/heaters is switched on/off by the defrost timer, and choosing the correct terminals will get you power all the time even if you end up jumping to a separate unused terminal to supply your power during fan/heater switching. The braided heaters are available in multiple lengths but aren't designed to go through bends other than the one or two close to the pan so this doesn't work if your running around the walls of the freezer before you exit the freezer wall, but work very well for drains that after 2 or so bends head through the back or side wall.

Yeah, I know about those types of heaters. That's what was there when I started on this issue. In fact, I have a kit of various lengths of 120V braided heat cable that was given to me by one of the maintenance guys when I started work here. I thought about using them, but I ordered a RayChem 120V 12' heat cable with a NEMA 5-15 plug from Grainger. I re-piped the drain today and tapped into the light circuit on top of the box. Ran it in liquid tight conduit, mounted an indoor/outdoor 1-gang rectangle box up behind the evaporator coil so no one can mess with it and installed a receptacle cover enclosure.

Question. Where would you get 240V power all the time from the terminal block in the evaporator coil? As I said, I can get it between "N" and "3" when it's in defrost or I can get it between "N" and "4" when the fans are running, but there is no non-switched, all the time, 240V circuit at the terminal board. I would need to pull another wire from the condensing unit on the roof, which would have been a lot more trouble than installing a receptacle behind the evaporator coil.

Anyway, thanks for all the advice and suggestions everyone. I really appreciate it.

I've seen outlets inside the freezer for the drain line heater.

Powered from the light circuit.

Convenient place to plug in the light when your working in the freezer.

Exactly!

[icemeister]

...Question. Where would you get 240V power all the time from the terminal block in the evaporator coil? As I said, I can get it between "N" and "3" when it's in defrost or I can get it between "N" and "4" when the fans are running, but there is no non-switched, all the time, 240V circuit at the terminal board. I would need to pull another wire from the condensing unit on the roof, which would have been a lot more trouble than installing a receptacle behind the evaporator coil...

While connecting the drain line heater to the fans is usually sufficient, if you need constant power in a hurry, just install relay to switch between 3 and 4...with the NC contacts wired to 4, the NO to 3 and the coil to 3.

Voila...constant power.

[2sac]

You said it went to #3 and I'm saying move it to # 4
Also if you have to splice just use butt connectors with heat shrink tubing.

Agree

Stay away from a gfci. It will get wet. It will trip. It will get knocked out from employees stacking boxes. You will be back repiping.

[prorefco]

I have never had a problem using terminal 4 on the coil terminal board.

Also, when installing an outlet inside the box, make sure you seal the wires inside the conduit just outside the box.

[SandShark]

While connecting the drain line heater to the fans is usually sufficient, if you need constant power in a hurry, just install relay to switch between 3 and 4...with the NC contacts wired to 4, the NO to 3 and the coil to 3.

Voila...constant power.

If you saw the end of the coil with the controls and wiring, and the conditions I'd have to do that under, you'd understand why that's impossible to do. It would be easier to pull another wire.

Agree

Stay away from a gfci. It will get wet. It will trip. It will get knocked out from employees stacking boxes. You will be back repiping.

It remains to be seen if the receptacle will will sense a path to ground and trip. I don't think that will happen. It will not get knocked out from employees stacking boxes. It's high up, behind the evaporator coil where boxes cannot be stacked. Repiping what, the drain? What makes you say that?

[Fridge Repairer]

I recommend not putting a GFI outlet inside the freezer unless you enjoy working on frozen drain lines! I also highly recommend using a trap because if you don't you will get snow build up in drain opening. Best of luck. In freezers I like to use Tee's with cleanouts instead of elbows....then when the drain line freezes over all I have to do to clear out the ice is heat up a piece of threaded rod and shove it thru the drain.

[SandShark]

I recommend not putting a GFI outlet inside the freezer unless you enjoy working on frozen drain lines! I also highly recommend using a trap because if you don't you will get snow build up in drain opening. Best of luck. In freezers I like to use Tee's with cleanouts instead of elbows....then when the drain line freezes over all I have to do to clear out the ice is heat up a piece of threaded rod and shove it thru the drain.

Yeah, I've been warned multiple times now not to use a GFCI, but I appreciate your repeating that warning. I think I get it. Trap has been installed, but thanks for the tip. Heat up a piece of threaded rod, huh? I'll have to write that one down so I don't forget. Thanks!