Defrost Timer - Stop Compressor or Not ?

[hvac-user]

My question pretains to a walk in freezer with a Copeland compressor (exterior of bldg.) 40ft. from walk in cooler (inside bldg). Evaporator is higher then compressor.
I'm new to refrigeration and have seen defrost timers wired to shutoff the compressor and liquid solenoid valves and some that only shut off liquid solenoid valve and let the compressor cycle on pressure. Some defrost timer installation instructions actually show shutting off the compressor and using the temperature switch to shutoff the liquid solenoid but not the compressor. My question is what method is best? I'm leaning to using the defrost timer in series witht the temperature switch and just letting the compressor run on pressure control. From everything I gather in studies that would allow the liquid to stay out of the EVAPs during off cycling (both temperature and defrost). But is this as safe as also turing off compressor?

[Moparmyway]

IMHO, use the timer to cut off the liquid solenoid.

[captain123]

IMHO, use the timer to cut off the liquid solenoid.

I agree, use a timer.

[skpkey9]

Systems should be on a pump down, Timer controls the solenoid...

[hvac-user]

Thanks for the advice. I'll wire the valve in series with the thermostat and defrost timer. Is there any real concern about only having pressure for the compressor controls...i mean the failure of one pressure switch could cause compressor problems?

[hvac-user]

Thanks for the advice............I'll wire the thermostat in series with the defrost timer and close the liquid valve. So no real concern about running the compressor with just the pressure switches for control?

[skpkey9]

If you lose your charge low pressure switch will catch... I like to use the dual pressure controls that have a manual reset on high pressure switch if system does not have one I will usually install a screw on manual reset high pressure cut out... other than that you should be fine...

Hope this Helps...