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  1. #1
    Join Date
    Nov 2003
    Location
    South Carolina
    Posts
    1,167

    R404 freezer drawers under cooktop

    Hi guys hope yall can help me out. These drawers are in a Dennys restaurant under their cook tops. Condensing unit is on the roof and it runs 3 different small evaporators with 2 drawers each one of top of the other under the cooktop. Not really sure how common these are but this is the problem. When I got there all 2 of the evaporators cooling the box to about 34* and one of them cooling at 27* box temperature. On the roof the line is all frozen up including about half of the compressor. The evaporators have some frost on them but not blocked and fans are turning at the evaps. Ive got a clear site glass my low side pressure is 35 and high side is 320. Ive got a 14 degree line temp at the compressor. These evaporators are small and very difficult to get to with no service port fittings. Anyone who can help me out? Im primarily an HVAC guy who was thrown into these restaurants and Im a bit rusty. These drawers are low temp and not med temp.

  2. #2
    Join Date
    Jan 2010
    Posts
    6,829

    Hmm

    Problem i have found with these is cooks don't close drawers half the time and so the evaporators freeze up. Or the drawer seals are not sealing because of misaligned drawers. Did you check your defrost clock when you arrived ? It may have just came out of defrost before you got there giving you a false indication of the coil. 320psi on the high side is to high unless its say 80* outside or you have a restriction. Is your outside coil clean ? What kind of head pressure control ? Fan cycling ? 14*= 50psi-35psi=15* superheat is high. Should be around 4-6* @ evaporator. Were just getting started.

  3. #3
    Join Date
    Feb 2010
    Location
    butler pa
    Posts
    1,073
    +1 on the drawers not being closed..
    door gaskets bad..
    drawers being diamonded due to being slammed shut w knees...
    those line cooks can be the root of the problem..
    id check and see if they are shut when you get there next time....

    we had one dennys the walk in would always freeze up...
    found the door open to walkin most times i got there...(they were in such a hurry they couldnt take the time to use the door thus leave it open )
    installed a baseball bat closer on it..
    strangely after that the freezing up stopped...

  4. #4
    Join Date
    Aug 2008
    Location
    Pittsburgh PA
    Posts
    4
    NO ice on the coils but ice on the compressor and suction line! Liquid in the suction line! If you have 3 seperate evaporators, you hopefully have 3 liquid line solenoids and thermostats. I think 1 of the 3 t.x.v.s is overfeeding. Try to cycle 1 thermostat off at a time, when the suction pressure drops and the frost goes away you found the overfeeding t.x.v.

  5. #5
    Join Date
    Aug 2007
    Location
    Winter Haven, FL
    Posts
    4,380
    Moisture in system.

  6. #6
    Join Date
    Dec 2000
    Location
    Flat Rock, NC
    Posts
    463
    Where are you in sc , I put some of these in for dennys back 15-18 years ago and yes they are godawful to service.

  7. #7
    Join Date
    Nov 2003
    Location
    South Carolina
    Posts
    1,167
    Quote Originally Posted by codgy View Post
    Where are you in sc , I put some of these in for dennys back 15-18 years ago and yes they are godawful to service.
    Im in the upstate in Greenville. I use to do a good bit of refrigeration but in the past 5 years its been mainly HVAC until I got thrown into all these Dennys and in all honesty its a god awful mess...not a good situation for me to get acclimated again. It seems every call I get is some kind of weird freaky thing going on. In this particular Dennys both defrost timers are open and coated with egg, sausage grease you name it but the timer to this 404 drawer is still working. I felt today it may be over charged so I reclaimed refrigerant just until I got bubbles in the sight glass and and let it run till it equalized. Now Ive got a frosted up line but at least the compressor is no longer frozen. Ive got 25 pounds on the low side and 225 on my high side. When I check temp on the line at the compressor my temperature is swinging wildly from 23* then within minutes it will go down to 6* but the low side pressure remains constant at 25. Im thinking maybe moisture or a bad expansion valve on one of the evaps but im getting frustrated. Climbing up and down the side of this building is wearing on me. Im considering just dumping the system refrigerant and evacuating then starting over just to rule out contaminants. The gaskets on the drawers seem to be ok and they are closed. The real frustrating part of this whole thing is while im sitting there scratching my head over this it appears the condensing unit for the ice machine is now malfunctioning even as im standing there. The drawer set up just seems to me to be a very bad idea considering who is opening and closing them. Most of these drawers are beat all to hell.

  8. #8
    Join Date
    Nov 2003
    Location
    South Carolina
    Posts
    1,167
    Quote Originally Posted by VTP99 View Post
    Problem i have found with these is cooks don't close drawers half the time and so the evaporators freeze up. Or the drawer seals are not sealing because of misaligned drawers. Did you check your defrost clock when you arrived ? It may have just came out of defrost before you got there giving you a false indication of the coil. 320psi on the high side is to high unless its say 80* outside or you have a restriction. Is your outside coil clean ? What kind of head pressure control ? Fan cycling ? 14*= 50psi-35psi=15* superheat is high. Should be around 4-6* @ evaporator. Were just getting started.
    Although the defrost timer is in poor condition and coated with all sorts of grease and other renderings as its located right under the dripping cook tops it is working and it was not just coming out of defrost. The drawers do seem to seal ok on this particular system so I dont feel its drawing in any excess air to the point of causing this sudden problem. It does have a fan cycling control that cuts out at 150 and cuts in at 250. It had a malfunctioning duel pressure control that I replaced. Outside ambient is 70. These drawers are deep with the evaps deep inside them at the back and its a choir just to squeeze my big butt up side the hole to try and get any kind of temp of the line at the evap. Imagine doing that while you have 3 cooks stepping all over you. So Ive been taking my temps at the line at the compressor. At the compressor now I have a low side line temp swinging from 23* all the way back down to 6* then back up again all withing minutes and its continuous after 2 hour run time. My low side pressure is now 25 and high side is maintaining steady at 225. Box temp can get down to about 28* and thats about it. Coil on condenser is clean and evap coils are clean.

  9. #9
    Join Date
    Jan 2010
    Posts
    6,829
    Do you have EPR,s on the suction lines of each evaporator ? The Denny's I've worked on had them on the backside of the cook line wall up in the drop ceiling. Suction lines continued on to the roof top condenser which contained three compressors.

  10. #10
    Join Date
    Nov 2003
    Location
    South Carolina
    Posts
    1,167
    Quote Originally Posted by VTP99 View Post
    Do you have EPR,s on the suction lines of each evaporator ? The Denny's I've worked on had them on the backside of the cook line wall up in the drop ceiling. Suction lines continued on to the roof top condenser which contained three compressors.
    What is an EPR? I havent looked up in the drop ceiling yet.

  11. #11
    Join Date
    Mar 2007
    Posts
    543
    Quote Originally Posted by hackmaster View Post
    Im in the upstate in Greenville. I use to do a good bit of refrigeration but in the past 5 years its been mainly HVAC until I got thrown into all these Dennys and in all honesty its a god awful mess...not a good situation for me to get acclimated again. It seems every call I get is some kind of weird freaky thing going on. In this particular Dennys both defrost timers are open and coated with egg, sausage grease you name it but the timer to this 404 drawer is still working. I felt today it may be over charged so I reclaimed refrigerant just until I got bubbles in the sight glass and and let it run till it equalized. Now Ive got a frosted up line but at least the compressor is no longer frozen. Ive got 25 pounds on the low side and 225 on my high side. When I check temp on the line at the compressor my temperature is swinging wildly from 23* then within minutes it will go down to 6* but the low side pressure remains constant at 25. Im thinking maybe moisture or a bad expansion valve on one of the evaps but im getting frustrated. Climbing up and down the side of this building is wearing on me. Im considering just dumping the system refrigerant and evacuating then starting over just to rule out contaminants. The gaskets on the drawers seem to be ok and they are closed. The real frustrating part of this whole thing is while im sitting there scratching my head over this it appears the condensing unit for the ice machine is now malfunctioning even as im standing there. The drawer set up just seems to me to be a very bad idea considering who is opening and closing them. Most of these drawers are beat all to hell.
    Are all txv sensing bulbs installed properly? On tight, insulated, and so on. The only other advice I can offer is do not get frustrated.

  12. #12
    Join Date
    Jan 2010
    Posts
    6,829
    Hackmaster,
    The EPR is a evaporator pressure regulator. If you have them on the suction lines there will be a dust cap you remove to access a allen screw. Adjusting will regulate the evaporator outlet pressure.

  13. #13
    Join Date
    Aug 2002
    Location
    Southold.calm
    Posts
    6,355
    Quote Originally Posted by hackmaster View Post
    What is an EPR? I havent looked up in the drop ceiling yet.
    Should be mounted in or near the case.

    Looks like this
    Attached Images Attached Images  

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