General Description; Overview; Flow Rate Based Control - Grundfos Geo-Flo Universal Pump Controller Installation, Operating And Maintenance Manual

GEO-FLO UNIVERSAL PUMP CONTROLLER: UPC-GEO | 1

General Description

Overview

The Geo-Flo Universal Pump Controller (UPC-GEO), designed in collaboration with Grundfos, is a 24VAC pow-
ered controller that operates a one- or two-pump variable speed flow center system to provide accurate pump
control and feedback resulting in the lowest possible power consumption for the pump(s) and system (PWM
output only; feedback not available for 0-10 VDC output). Instantaneous pump power in Watts is displayed
on the back-lit LCD (PWM output only) along with other system parameters depending on which sensors are
installed. The installation technician decides whether to control the pump speed based on flow rate set points
or differential temperature (∆T) set points. Installing a single Grundfos Vortex Flow Sensor (VFS) with the
UPC- GEO allows the system to be controlled using a flow rate set point input into the controller based on the
requirements of the heat pump. The controller allows separate flow rate inputs for two-speed heat pumps,
which results in substantial energy savings due to lower flow rate requirements in first-stage heat pump opera-
tion. The Grundfos Vortex Flow Sensor provides both flow rate and temperature feedback which is displayed
on the controller. Differential temperature (ΔT) control requires the addition of two immersion thermistors and
allows separate ΔT inputs for heating and cooling modes. Installing both a VFS sensor and thermistors allows
the UPC-GEO to display flow rate, ΔT, and heat of extraction/rejection in KBTU/H. Two lockout modes allow
the installer to choose whether to lock the system parameters so they cannot be inadvertently changed or
to lock the screen so the feedback (temperatures, flow rate, power, etc.) are not displayed. A Meter mode is
included which allows the UPC-GEO to display temperature, flow, and MBtu parameters but does not control
the pump(s).
Flow-rate based control (Grundfos VFS flow sensor required)
The UPC-GEO receives a 24VAC signal from the heat pump or thermostat for stage-one or stage-two heating
or cooling. The UPC-GEO then provides a PWM signal to the variable speed Magna GEO 32-140 pump (or 0-10
VDC output for other pumps) and monitors the output signal from the Grundfos VFS flow sensor and pump.
The UPC-GEO increases or decreases the pump speed based on the flow rate input into the controller and the
actual flow rate of the system. For higher flow rate and/or head loss systems a two-pump variable speed flow
center may be required. This flow center consists of a single variable speed Magna GEO 32-140 and a constant
speed UPS26-99. The UPC-GEO attempts to satisfy the flow rate requirement by first using the more efficient
Magna GEO 32-140 pump. If the Magna GEO reaches its maximum performance level before satisfying the flow
rate set point requirement, the UPC-GEO energizes the UPS26-99 and ramps the Magna GEO down to match
the requirement, thereby minimizing pumping power. The UPC-GEO saves the pump signal settings to allow
it to quickly deliver the required flow rate on subsequent calls for heating or cooling. On two-pump variable
speed flow center systems the UPC-GEO energizes the UP26-99 for 30 seconds every 72 hours if it has not run
during that same period.