Bell & Gossett 138808 GMU30 Glycol Make-Up Unit

Closed-loop heating and cooling systems can use the Bell & Gossett 138808 GMU30 with 30-gallon storage, approximately 1.5 GPM pump flow, 115 V single-phase power, polyethylene storage, steel support, and pressure-switch control.

The listed cut-out pressure is approximately 50 psi, which provides a control reference for commercial hydronic loops. The unit supports sealed-system make-up service, but actual pressure settings, fluid compatibility, discharge piping, and safety-device requirements must match the installed system.

System Components

- Thirty-gallon storage capacity establishes the reservoir volume for make-up planning.
- Approximately 1.5 GPM pump flow provides the listed delivery reference for system evaluation.
- 115 V single-phase power supports control-panel and branch-circuit planning.
- Polyethylene storage construction identifies the documented tank material.
- Steel frame construction provides the listed support arrangement for equipment placement.
- Pressure-switch control manages automatic start and stop based on system pressure.
- Approximately 50 psi cut-out pressure establishes the listed control reference.

Performance and Application

The GMU30 is listed for sealed hydronic systems and commercial heating or cooling loops. Its approximately 1.5 GPM flow and 50 psi cut-out reference describe make-up operation, not guaranteed system performance. Final selection requires review of system volume, pressure range, fluid type, and required replenishment rate.

Installation Requirements

Install the unit on a level, secured base with service access, support the discharge piping independently, inspect fittings for leaks, and provide appropriate pressure relief and expansion controls. Glycol installations require secondary containment, while the make-up connection must match the system’s piping and pressure requirements.

Warranty and Maintenance

Bell & Gossett provides an 18-Month Limited Warranty from shipment or a 1-Year Limited Warranty from installation, whichever occurs first, covering defects in materials and workmanship. Proper installation and intended use are required, while misuse, alteration, negligence, and contrary operation are excluded. Mulmotor provides pre-purchase product guidance and order-related customer support.