Coldroom control

[R1976]

Hi all,

We have a 5 degree coldroom to fit out with a 40m pipe run. We are going to control the condensing unit with a signal from an Elliwell controller and control panel.

Would it be better to use a solenoid valve and control it by LP pumpdown?

[Magoo]

Hi R1976.
Use the Elliweel control signal in compressor control circuit with Hp/Lp, control solenoid with compressor run/stop. Put the solenoid close to evaporator to stop liquid line hammer and cracked pipes. Once system up and running leave chiller door open and ice up evap and set LP trip at that suction pressure at compressor. And re-cycle for air defrost. All bases covered, ice ups and temp control.
Next have a serious talk to sales engineer for selling a 40 metre pipe run system.

[R1976]

Thanks Magoo,

I was thinking of putting the solenoid above the ceiling on top of the cold room, which is about 1 metre from the expansion valve. P traps top and bottom of coldroom suction riser.

Main suction line is sized at 1"1/8, Evap connection is 7/8". Can I reduce down on top of coldroom, this means I can bend the p traps into 7/8" pipe and less brazing for me:D?

What would have been a better alternative to this system?

[Magoo]

R1976.
I dont know the system capacity, but I would double P trap riser from evap in 7/8 to keep gas velocity up for oil return and increase to 1 1/8 for suction run to compressor to reduce pressure drop in long pipe run. Double check line losses versus system capacity.

[R1976]

Magoo,

By double p traps do you mean one at the bottom and one at the top of the evap riser?

[Magoo]

R1976. yes top and bottom