1 walk in, 1 reach in, 1 condenser.

[craig1]

Just picked up a new account today, a convenience store with an interesting install. Its a 10 door display walk-in for beer and a 5 door reach in for milk, packaged meat, and cheese connected to one condenser. The evaps on the walk in were solid blocks of ice and the walk in stat was set to 20 degrees.

The stat on the walk-in controls an LLSV at the condenser out in the parking garage. The reach-in has a stat which controls an LLSV in the reach-in. See the problem? The reach in can't cool unless the walk-in is asking for cooling. If they set the walk-in warmer than 20, the reach-in gets warm. The walk in has an EPR, don't know what its set at.

The owners bought the store about a year ago and the compressor bit the dust 2 months ago so they had a new comp put in it. The installer apparently forgot to account for flooding charge so the system was seriously undercharged now that its cold out. I think its going to better now that it's topped up, but it can never be perfect because the two cases are so different. The previous owners told the current owners that they turned off the condenser every night to save electricity, but I suspect it was also to prevent icing. I bet that heat cycled beer was delicious

I'm thinking of adding a LLSV for the walk-in evaps so that each case can run independantly. Would this work? would I need an EPR on the reach in? or should it be OK?

Adding a separate condenser would be best, but that is not possible since the store in a high rise and the condensers are out in the parking garage and the lines are not accessible.

[pauls heating &]

add a water cooled condenser to one system

[Herb1025]

Do they have two Liquid lines Some systems will have two LLSV with two controls and the one two be kept warmer will have an EPR to rise the suction pressure so It can maintain that warmer temp

[Dad]

Multiple evaps single condensers are common place in CStores and small groceries.

Moving the valve to the evap on the walk in will work but what refrigerant are we talking about?

The PR is used because of the size difference in the WI and the RI. It will help with that new compressor by keeping a constant return pressure and help prevent flooding but it really should have a suction accumulator too.

[craig1]

what refrigerant are we talking about?

R-22

[neumonic]

The stat on the walk-in controls an LLSV at the condenser out in the parking garage. The reach-in has a stat which controls an LLSV in the reach-in. See the problem? The reach in can't cool unless the walk-in is asking for cooling. If they set the walk-in warmer than 20, the reach-in gets warm. The walk in has an EPR, don't know what its set at.I'm thinking of adding a LLSV for the walk-in evaps so that each case can run independantly. Would this work? would I need an EPR on the reach in? or should it be OK?

That seems strange that it has an epr and a stat and LLSV for the walk in. I would remove that solenoid at the condenser and put it on the walk in alone. Unless that is what is there for defrost? you mentioned the coils were ice blocks? what is used for defrost?

[neumonic]

or better yet put the epr on the reach-in and run the walk-in off LPC

[Dad]

R-22

Grab a time clock and put it in a 30 minute air defrost twice a day on the walk in. The R22 coils have a tendency to ice up.

[pecmsg]

Just picked up a new account today, a convenience store with an interesting install. It’s a 10 door display walk-in for beer and a 5 door reach in for milk, packaged meat, and cheese connected to one condenser. The evaps on the walk in were solid blocks of ice and the walk in stat was set to 20 degrees.

The stat on the walk-in controls an LLSV at the condenser out in the parking garage. The reach-in has a stat which controls an LLSV in the reach-in. See the problem? The reach in can't cool unless the walk-in is asking for cooling. If they set the walk-in warmer than 20, the reach-in gets warm. The walk in has an EPR, don't know what it’s set at.

The owners bought the store about a year ago and the compressor bit the dust 2 months ago so they had a new comp put in it. The installer apparently forgot to account for flooding charge so the system was seriously undercharged now that it’s cold out. I think its going to better now that it's topped up, but it can never be perfect because the two cases are so different. The previous owners told the current owners that they turned off the condenser every night to save electricity, but I suspect it was also to prevent icing. I bet that heat cycled beer was delicious

I'm thinking of adding a LLSV for the walk-in evaps so that each case can run independently. Would this work? Would I need an EPR on the reach in? Or should it be OK?

Adding a separate condenser would be best, but that is not possible since the store in a high rise and the condensers are out in the parking garage and the lines are not accessible.

Get the charge correct.

Move the LLSV from the condensing unit and install it in the walk-in.

Install a time clock at the condensing unit, off cycle for 1 ½ to 2 hrs when there closed. (If you can wire this into the LLSV’s that’s even better but not required)

Make sure the crankcase heater is working.

Adjust your SH in both cases.

Set the thermostats with ice water.

[craig1]

Grab a time clock and put it in a 30 minute air defrost twice a day on the walk in. The R22 coils have a tendency to ice up.

It actually had a clock set for 1 hour once a day. I added a second defrost period.

I suspect the freeze up was due to the case being below freezing, so even in when the timer kicked in the ice didn't melt. There was a leaking water heater sitting on the ceiling of the wall of the walk in and icicles were forming inside the cooler where the water was leaking in so it definitely was below freezing in there.

They had cranked the stat down to get the compressor to run long enough to keep the reach-in cool. I suspect with the refrigerant topped up the reach-in should cool a bit better and not require the walk in to be set so cold.

[Dad]

Good that it's got a clock. I think everyone understands the stat setting on the walk in being 20 and that's why it froze up. Pec has the right idea above and in one place. But a suction accumulator, even a small one will keep that compressor from slugging back.

note, since the water heater is leaking and should be replace, move it from the top of the walk in or make sure it's supported from a different source.

[icemeister]

Since you have a single defrost timer at the condensing unit I suggest you use it to control the liquid line solenoid at the condensing unit for pumpdown on defrost and add another LLS at the walk-in controlled by the existing thermostat.

Then the beer case and the walk-in each have independent temperature control and the system will then have a master defrost control.

The EPR really isn't necessary here unless you're needing to maintain a high relative humidity in the walk-in box. Actually, in situations like this where humidity control isn't a big factor and there are only two circuits involved, I've found it's better to not have an EPR on either circuit. Without EPRs, when one circuit is satisfied, the compressor will have more load to run on if there's no holdback valve there and that circuit will tend to cycle off faster.

[Dad]

What do you think about the slugging Mr. C.. ?

Do you agree with the suction accumulator install? I would guess it would also depend on the system capacity but it would provide decent compressor protection since they just replaced it.

I also wonder what sort of climate we are discussing. Is this store in a cold climate?