Issue:
Does this chiller have a relief valve?
Resolution:
CGAM
The Pueblo CGAM chiller does not have a refrigerant relief valve. The main reason is that there is nothing on the unit that qualifies as a pressure vessel requiring relief (BPHE evap, compressor, MCHE coils). This is similar to the CGAF 20-60T chiller - see Do our units have Pressure Relief Valves?
Unit pressure relief is via the copper lines. In case of high pressures, a u-bend would rupture on the tube and fin condenser coil.
There is one fusible plug on the receiver tank on CGAM with microchannel condensers.
Chicago Relief valves are also not available on the CGAM chiller.
The relief valve (or tube rupture) is the third level of protection for the chiller. The first is the Adaptive Controls pulling back capacity before the chiller hits a limit. The second is the high pressure cutout switch shutting off the compressors when the chiller gets to the limit. The third is the relief valve or tube rupture.
ACSA
There is one pressure relief device on ACSA which is the fusible plug on the receiver tank. ACSA is all MCHE CONDENSER with one receiver per V.
It acts as a relief valve in the event of fire. It is required by ASHRAE 15 code. The plug material will melt away so it is not resettable but it is replaceable. Melting point of 232°C (450°F)
Per UL 1995 33.10 equipment shall have protective means such as a fusible plug, a rupture member, soldered or brazed tubing joints, special terminals, or pressure relief valves, or shall be so constructed that some part of the system will safely relieve the pressure in case of fire.
Fusible Plug Explained - saVRee
Notes:
Isolate refrigerant in CGAM condenser coil
What is the purpose of a liquid refrigerant receiver?
Facts:
- Air-Cooled Chiller (Pueblo) (CGAM 20-130 Ton)
- Air-Cooled Chiller (Pueblo) (ACSA 140-230 Ton)
Document Identifier: DOC-101874
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.