Leak in evap or condensor rads, restaurant walk in coolers, only ~ 5years old

Leonard

Own several restaurant walk in coolers. New tenant of 2 years claims evap and condenser rads leaked. I believe they only had ~ 5 years of total use ( previous tenant installed them).

Evap and condensers looked very clean, like new. System history is : ran for 3 years, then building vacant and thieves stole 4 ft of copper outside, system open for 3 years. Then repair and ~ 2 year run time with new tenant. Tenant says a refrigeration guy says being open to atmosphere for years caused corrosion. Does this sound reasonable? (Not a money issue as tenant is responsible for all repairs in lease)

After copper theft I wrapped pipe ends with aluminum foil to keep out bugs/dirt ( not a hermetic seal) . And stored compressor/condensor units indoors.

Len
Mechanical Engineer

HVACNUT

A lot of walk ins dont hold a lot of refrigerant. If there's a leak it won't take long. The circuit usually pumps down to the condenser when the cycle is finished. Seems like it need a nitro or sniffer test.

Ironman

Possible. Moisture in the air when mixed with particular refrigerants or oil will produce an acidic mixture. The compressor is usually the first thing to fail.

Leonard

Have 4 systems, all opened by copper thieves (for 4 ft of copper pipe each) , plus 1 or 2 spare compressor units.

Think pump on one did fail. Tenant said evap leaked on another. Outside of evaps looked so clean I thought they were new.

ratio

I wouldn't have much confidence in a system that was open for years. Tape is a temporary fix to keep bugs out overnight, for long term storage I'd burn it shut & put a few hundred lbs of N₂ in it.

unclejohn

Acids in the pickle juice and salad dressings are a major contributor to evap leaks. Can't explain the condenser leaks. I doubt that being open to the atmosphere had any effect on the copper.

Leonard

Suppose could be vinager acid vapor in the air, condensing on evap. But on casual visual inspection evap and it's fins looked new. (after old tenant left)

Evap assembly looked so new and clean , I didn't give it a hard look between the fins at tubing. Old tenant went bankrupt, so they usually don't clean anything when that happens, yet evaps were clean. Have not looked at them now new tenant is in there.

JUGHNE

Are they sure the new lineset/couplings is not the leak?

Leonard

No idea, he only told me about it after someone fixed it. In lease he agreed to be responsible for all repairs. Just wanted to know if it's likely real or if he's telling me a fairy tail.

Leonard

Walk-in coolers.( footprint ~ 10 X 15 ft, or less)

Other strange thing on one unit is pump comes on and only runs ~ 5- 10 seconds then shuts off. Might be off for long time ( > 5-15 minutes) . Noticed it in spring and summer (only time I was there) , New Hampshire . Is this normal? Hi side pressure switch hi/low set too close maybe? Acumulator too small, pump too large? No experience with walk-ins.

I think pump charges an SMALL accumulator and evap thermostat only opens a solenoid to let refrigerant flow if walk-in is too warm. Walk-ins are set up so each evap has it's own pump/condensor , only one evap per walk-in


Compressors, and typical evaps.

JUGHNE

Usually, T-stat inside walk in box on back side of evap, (air inlet).
It closes on temp rise and solenoid valve opens in liquid line.
Pressure rises in suction line and switch starts compressor. Usually should run until T-stat is satisfied. Then sol valve closes and unit pumps down.

You may have heard a second pump down cycle that lasts maybe 5 seconds. The gas expands in the suction line and activates the pressure switch again.
Adjusting the pressure switch may stop the redundant re-pump down.

Leonard

There was only one pump run , it lasted ~ 5 seconds. Sheet metal rattles so no chance I missed hearing it run.

I was working on other things in the area. All was quite for a long time (maybe 15 minutes) then ~ 5 seconds pump run. After maybe 15-30 minutes later there was another 5 second pump run , then none till I left (at least 10 minutes).

Just struck me strange that it would have such a short run time. Is this type operation normal? Or do you think this will lead to an early failure in future?

Guessing pump or high side solenoid is leaking thru a bit.

Ironman

Leonard said:

There was only one pump run , it lasted ~ 5 seconds. Sheet metal rattles so no chance I missed hearing it run.

I was working on other things in the area. All was quite for a long time (maybe 15 minutes) then ~ 5 seconds pump run. After maybe 15-30 minutes later there was another 5 second pump run , then none till I left (at least 10 minutes).

Just struck me strange that it would have such a short run time. Is this type operation normal? Or do you think this will lead to an early failure in future?

Guessing pump or high side solenoid is leaking thru a bit.

The compressor valves probably have slight leakage. This is normal.