High Freezer temperature

[chillyblue]

Hi

I have a walkin freezer which used to operate at about -18degC. the owners shut it down to have a new floor laid, now its been switched back on, the temperature in the room does not drop below minus12degC. the system is running on R22 suction pressure of 21psi discharge pressure seems a bit low around 150psi subcooling very good and with a clear sight glass, superheat around 8degC, The evaporator is clean, clear and not icing up, i've tried opening the TEV and shutting the TEV, neither seemed to have much effect.

Any ideas??????????

CB

[Paulajayne]

Compressor or low on gas

Paula

[chillyblue]

Hi

I've checked the compressor (had the head of and check pistons and valves/plate) all perfect. gas charge seems fine too!.

I think the system is undersized

CB

[old gas bottle]

when its had a new floor laid it should be bought down in stages over a week, 1=+4, 2= -5ish, then let in go at its target temp,there will be alot of heat to come out of the new floor,as said, one week, if it dont make it soon after that start looking at undersize kit or fault finding. they did renew the floor insulation ? yes.

[Samarjit Sen]

The system may be low on gas. But asw Old Gas Bottle says, if the floor has been laid a fresh, then give it some time and also check the floor insulation.

[lana]

Hi everybody,

I do agree with old gas bottle as long as there is no refrigeration problem.

Check the attached file.

Cheers

[Peter_1]

If it is concrete, then you have to wait 28 days before freezing.
Good link Lana, thanks

[Temprite]

Hi

I have a walkin freezer which used to operate at about -18degC. the owners shut it down to have a new floor laid, now its been switched back on, the temperature in the room does not drop below minus12degC. the system is running on R22 suction pressure of 21psi discharge pressure seems a bit low around 150psi subcooling very good and with a clear sight glass, superheat around 8degC, The evaporator is clean, clear and not icing up, i've tried opening the TEV and shutting the TEV, neither seemed to have much effect.

Any ideas??????????

CB

Had the same problem with a freezer room which had a new condensing unit installed.

Told customer that original unit was undersized but he insisted on changing with a unit of similar capacity.

The walls of the room were water logged also,and unit was turned off for about a one week period.

Unit got to about -12 degrees c and stayed there for about a week, after that it pulled down to the correct temp.

[NH3LVR]

Had the same problem with a freezer room which had a new condensing unit installed.
Unit got to about -12 degrees c and stayed there for about a week, after that it pulled down to the correct temp.

This is something I have seen many times in Blast Freezers. They typically have no source of cooling except for the Blast Coil, and are operated seasonally.
On startup for the season, it would take a couple of days for the heat to come out of the floor, and normal operation to resume.
Please note that these freezers I refer to had no insulation in the floor.
I have also seen this in Spiral Freezers with water saturated Fiberglass insulation in the floor.