Cold store low temperatures and defrosting cycles create significant variations in air pressures. These subject the doors, walls and ceilings to constant strains which have to be relieved by heated relief valves. These balance the internal and external pressures.
Loheat makes valves which are designed for easy installation in wall thickness from 65 to 150mm with extension tubes for thicker walls.

Loheat PRV1 Pressure Relief Valve                       
Capacity 250 cubic metres 0-35°C
Quick and easy installation
Suitable for panels 65mm up to 150mm as standard
Easily adapted for thicker panels
105mm external diameter tube
Fine stainless steel mesh to screen out insects
Covers available in stainless steel or white painted aluminium
Separate indicator box is recommended as an add on to monitor the input power, showing when the PRV heater circuit is working

Loheat PRV2 Pressure Relief Valve
Capacity 120 cubic metres 0-35°C
Quick and easy installation
Panels from 80mm to 150mm
Extention tubes for thicker panels
Insect screen
90mm external tube diameter