suction probe

[headgasket]

Hi i am new to the supermarket game,but have been in the trade for over 25 years, could any one help me with this one, what causes the suction probe reading on some cases to go up and down, and not give a linear reading like evap probe, is this a indicator of a faulty probe,

[lowcool]

probably liquid,heat load and reaction time would want to be quicker assuming its eev jobby.without gettin to technical that is

[Silhouette]

Assuming you have an electronic expansion valve?
The controller will continually try to maintain the required TD between the two probes (Evap & Suction) but the suction pressure, evap temp and air flow will be constantly changing, depending on case type etc. So the valve will be under constant control change therefore the suction pressure and temperature will vary and will hardly ever give a straight line graph!!

[Eeram]

what causes the suction probe reading on some cases to go up and down


By saying this, how much is the variance? What Silhouette says is true. The controller will try to keep the superheat between the pre defined settings and the probe (sensor) reading will vary all the time.

Just make sure the probe (sensor) is properly secured at the 3 or 9 o' clock position. It is adviseable to insulate the probe.

10 Cabinets/Cases in a line up will give 10 different readings, even if they are all the same.

[Yuri B.]

In your place I would ask the admin. to delete the 3 last posts.

[lowcool]

came across a probe on a vertical of main suction line feeding a rack,found out later that it was fitted as a safety to shut down system if line got to cold,out with the oxy boiled off liquid in three sumps reset oil safetys all restarted ok,never did find out whose clever idea it was

[headgasket]

thanks for your replies, the probe is fitted on a sainsbury case and is a standard TEV ,and varies from -20c to -3, but the evap/ air of is -30c,THE freezer case next to this one suction probe -20c all the time apart from defrost, i have found this on three in a run, which are the ones that keep going into CPT.

[lowcool]

whats ctp oh while were at it whats cop?

[headgasket]

Critical product temperature, correct operating pressure. any jobs going in Adelaide,

[lowcool]

gday headgasket
always,had a chat with a mate yesterday,company callled frigrite is bringing out some scots,see if they like our 46 deg c summers.if your looking your better off going straight to the companies alot dont advertise unless their looking to poach,thats what it seems like

[Silhouette]

Can you tell me the case type?
On JS with TEV usually a Carel controller?
It could be refrigerant starvation. Check the TEV inlet filters, they may be blocked.