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PobodysNerfect
13-07-2004, 06:45 PM
ANSI / ASHRAE standard 15 (2001) defines a pressure vessel as "any refrigerant-containing receptacle in a refrigeration system" but continues by excluding, for example, evaporator coils and condenser coils from clasification as pressure vessels.

Also, any pressure vessel that contains liquid refrigerant that may be isolated by stop valves located anywhere in the system must be fitted with appropriately sixed overpressure protection?

So, must an evaporative condenser have a pressure relief valve, and must an evaporator (hot gas defrost - not electrical) have a pressure relief valve?

Saludos,

Jan

chemi-cool
13-07-2004, 08:23 PM
Hi Jan

It looks like the answer is in the question "that may be isolated by stop valves located anywhere in the system must be fitted with appropriately sixed overpressure protection"


If you have stop valves that isolate the evaporator or condenser then the answer will be yes according to ASHRAE .

Chemi :)

PobodysNerfect
14-07-2004, 05:57 PM
Hi Chemi!

Indeed, when you can trap liquid in a refrigeration system or if the pressure can rise above the design pressure (heating coil etc) you must have a relief device (according to standard 15).

Anyway, if a condenser (coil) is not classified as a pressure vessel, which always need a relief valve, then maybe it does not need any relief valve, as you not likely will fill it with liquid.

Saludos,

Jan

Volnei
18-07-2004, 03:00 AM
Hi Jan,

In a evaporator with hot gas defrost we usually have a pressure regulator valve to keep the pressure inside the coil during the defrost, so in my opinion, this valve works like a pressure relief valve.

Best regards.

Volnei

PobodysNerfect
19-07-2004, 01:14 AM
Hi Volnei,

Hot gas defrost could also be working with a HP float valve.

Anyway, if the hot gas pressure regulating valve should count as a pressure relief valve, then you can not have stop valves before or after.

Best regards,

Jan