Why is the top rim on prep cooler not getting cold?

[ectofix]

The “top rim” (as you called it) is called a COLD RAIL.

 

Could you please at least offer up some idea of who makes the one you’re referring to?  A model number would be nice too.

[fixbear]

Not knowing your make and model puts me at a handicap,  But the fact that it has a separate refrigeration circuit for the top rail means it’s a high end top.  Are all spaces full of pans?  They do not cool correctly if you leave one or 2 out.  Possible causes of your problem are that the condenser is not cooling enough or your charge is low.  Check your condenser fan and the air flow through the condenser.  Feel the liquid line at the bottom of the condenser or the filter dryer for temperature.  If near room temp you’ll need to check the charge.  If hot you lack air flow though the condenser.  This can be dirt in the condenser or fan not to speed.(bearings).

 

All this depends on the lower box being at the correct temp first. And that the thermostats are working correctly.

[fixbear]

I forgot to mention to check the upper temp control. If there is no call for cooling, it won’t cool.  Unfortunately I don’t have a clue as to what type of cold control you happen to have.

[henry]

Yes if you give me a make and model I may be able to help you out but the first thing to do is check and see if the solenoid is energized

[mewservices]

I put a new solenoid valve and TXV on it because the solenoid wasn’t working and I figured while I had it evacuated I might as well put a new TXV on it as well. The valve is energized and you can feel the refrigerant going by but it’s just not getting into the top rim(coils) in the top part. Bottom works great.

Here is a picture of the tag unfortunately the model number is not readable but the serial is.

Thank You so much!!!

 

 

 

Martin Wright/ Owner of M.E.W Services

-HVAC-R Technician

-Commercial Appliance Technician

-Foodservice Equipment Technician

-Residential Appliance Technician

-Electrician

 

(315) 573-5700

[mewservices]

Well I guess I can’t attach a picture. So anyway it’s a Delfield and it’s a S/C refrigerated base and reduced height rail. Like I said model number is no longer there but serial is 0506036001668M

134A- 32oz

Thanks again!!

[fixbear]

Tubing resriction like a pinch or bend for the top rail.

[mewservices]

I didn’t see anything 

[fixbear]

Usually where the tubing enters or exits the case.  What is the refrigerant and what refrigerant was it built with.  Sometimes they get a oil lock from congealing oil incompatibility or to much oil in the system.

 

Adjusting the TXV on a parallel evaporator system is also a bit difficult.

[ectofix]

Well then, maybe…

– a blob of sil-foss restricting flow?

– the new TXV is out of adjustment or possibly damaged during installation (brazed in?)?

– the new TXV bulb is improperly mounted?

– the new solenoid valve was maybe damaged during installation (brazed in?)?

 

Are you seeing any frost on the line feeding the cold rail?