Handling of MultiTherm® Heat Transfer Fluids


Drums should be protected from exposure to direct sunlight and/or precipitation. To prevent condensation due to temperature/humidity extremes, sealed drums should be moved inside at least 24 hours before system is filled.

System Filling 

Location - Fluid should be added at the lowest point of the system, preferably at the suction side of circulating pump to force air out of the vent valves. Aeration of the fluid should be avoided - do not add directly to the expansion tank.

Pump - Any portable or drum pump with sufficient capacity is acceptable. Do not use system circulating pump to add fluid since seal damage can result from running pump dry. All tubing, hoses, etc. should be oil resistant.

Valves - Open all vent/bleed valves as well as process block valves, control valves and all valves connecting system to expansion tank.

Filling - Add fluid to system. Close off vent/bleed valves when fluid runs out. Stop filling when fluid runs out of highest point.

Air Pocket Removal

Use system pump to circulate fluid slowly through system until all gas bubbles have escaped into expansion tank or have vented through vent/bleed valves.

Centrifugal Pump - Valve on pump discharge should be almost closed at start-up. Open valve slowly until 1/2 open and let fluid circulate.

Gear Pump - Cycle pump "on" and "off", gradually increasing "on" time until continuous operation is possible.

Cycle control valves until all loops are full. Add fluid as required to maintain level at 1/4 full in expansion tank.

Make sure Y-strainer (if installed) is clear before heater is operated.