Geo-Flo NP Series Installation guide

www.geo-o.com
NP Base Non-Pressurized Flow Centers
Installaon, Operang, and Maintenance Manual
Geo-Flo Corporaon
905 Williams Park Drive
Bedford, Indiana 47421, U.S.A.
Main Number: 812-275-8513
Toll Free: 800-784-8069
Fax: [phone]

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 NPBSeriesNon-PressurizedFlowCenters 
Table of Contents
General Descripon . . . . . . . . . . . . . 1
Available Flow Center Models . . . . . . . . 2
Flow Center Pump Sizing. . . . . . . . . . . 5
Installaon . . . . . . . . . . . . . . . . 6
Flushing and Purging . . . . . . . . . . . . 8
Start Up . . . . . . . . . . . . . . . . . .13
Maintenance. . . . . . . . . . . . . . . .15
Pump High Voltage Wiring . . . . . . . . . .17
Oponal Pressure Relief Piping . . . . . . . .18
Troubleshoong . . . . . . . . . . . . . .19
NOTES:
This guide provides the installer with instrucons specic to NP Base Flow Centers. Please refer to your
heat pump manufacturer’s instrucons or CSA/ANSI/IGSHPA guidelines for addional detailed ushing,
purging, and installaon informaon. Please review the enre IOM document before proceeding with
the installaon.
Geo-Flo Corporaon is connually working to improve its products. As a result, the design and
specicaons of products in this catalog may change without noce and may not be as described
herein. For the most up-to-date informaon, please visit our website, or contact our Customer Service
Department. Statements and other informaon contained in this document are not express warranes
and do not form the basis of any bargain between the pares, but are merely Geo-Flo’s opinion or
commendaon of its products.

General Descripon
The NP Series is a family of non-pressurized ow centers used for
closed-loop geothermal (ground source) heat pump systems. The
NP Series ow centers ulize a water column to provide the neces-
sary sucon head for the circulator pump, and to ensure a ooded
pump volute. Each NP Series ow center consists of a uid reservoir
(tank), ush and/or service/isolaon valves, and one or more pumps
housed in a foam-insulated cabinet. The valves included in each NP
ow center varies within the family of products. Review the follow-
ing secon on “Available NP Flow Center Models” for more informa-
on. Every NP ow center includes a sealing cap to ensure a closed
system and provides vacuum relief to prevent the reservoir from
dropping below atmospheric pressure when the loop expands (dur-
ing cooling season). A pressure relief valve prevents the reservoir
from being over-pressurized when the loop contracts (during heang
season). Since the NP reservoir can hold pressure, the air space at
the top funcons like an expansion tank in pressurized systems. The
NP reservoir provides an air separaon funcon due to the size of
the tank and design of the return piping.
1 | Installaon, Operang, and Maintenance Manual
Figure 1 shows the uid ow to and from the NP Base ow center. The uid is pumped from the ow center’s
tank on the le side, travels up through the sucon side isolaon valve, through the pump(s), and out the dis-
charge isolaon valve . The uid returns from the ground loop through the top right tank isolaon valve and is
directed to the tank where any air present in the uid is released.
Figure 1: Generalized uid ow
(components inside cabinet)
Out: From
Flow Center
to Heat Pump
In: From
Ground Loop
to Flow Center
To tank
From tank

Available Models
The NP Series of ow centers are available in several
models to meet the requirements of the specic instal-
laon and contractor preference. The following is a
brief descripon of each NP product. Note that each NP
product has a specic installaon manual. This manual
focuses on the NP Base. Consult the manuals for each
specic NP for further informaon.
NP Base (NPB) Flow Center:
The NP Base is a cost compeve model designed for
single geothermal heat pump installaons (one heat
pump on a dedicated ground loop) where the contrac-
tor chooses to install external ush valves, or chooses to
ulize internal headers (i.e. all loop circuits are brought
into the mechanical room). The NPB includes isolaon
valves on the pump sucon and discharge, and an isola-
on valve on the return. Field connecons to the NPB
are 1” NPT.
NP Flow Center:
The standard NP Flow Center is the original NP oering
and includes Geo-Flo’s Flo-Link double O-ring technology.
The NP is designed for single geothermal heat pump
installaons. The NP includes 3-way, 4-posion ushing
and isolaon valves that allow the contractor to ush the
heat pump and ground loop without addional valves or
plumbing. This NP may also be used with internal head-
ers. The 3-way valve on the sucon side of the pump(s)
can also be ulized to ll and drain the tank. The NP
Flow Center does not ship with any ngs. Hose kits are
available for installaon ease and exibility.
NPB Series Non-Pressurized Flow Centers | 2
Figure 2: NPB
Figure 3: Standard NP

NP Plus (NPP) Flow Center
The NP Plus has the same features as the NP but also includes an
external 3-way ushing/purging valve, and a set of Flo-Link X 1-1/4”
HDPE socket fusion ground loop adapters (Figures 4 and 5). This ad-
dional external 3-way valve allows the ground loop to be ushed
separately from the heat pump. Since the ground loop adapters
are included, a hose kit or a set of Flo-Link double O-ring adapters
are all that is required for connecon to the heat pump. The NP is
designed for single geothermal heat pump installaons.
NP Dual Circuit (NPD) Flow Center
The NPD has the same features as the NP and NPP but is designed
for installaons where two geothermal heat pumps share the same
ground loop. All 3-way valves are built into the NPD. Check valves
are included in the product to prevent the need to install external
check valves on each pump circuit. Hose kits are available for instal-
laon ease and exibility.
Figure 5: NPP
Figure 4: NPP with hose kit
Figure 6: NPD
3 | Installaon, Operang, and Maintenance Manual

NP Mul Circuit (NPM) Flow Center
The NPM is a family of mul-circuit non-pressurized ow centers that are used for two or more geothermal
heat pumps sharing the same ground loop. Since there are large number of available opons for the NPM,
please consult our website or the NPM literature for detailed descripons.
NPB Series Non-Pressurized Flow Centers | 4
Figure 7: NPM with circulators for each heat pump
Figure 8: NPM with central variable speed pump and zone valves for each heat pump

Flow (U.S. GPM) [l/s]
Grundfos Pump Performance Curves (Single Pump)
Head (Feet) [kPa]
UP26-116 UPS26-99 high spd UPS26-99 med spd UPS26-99 low spd
[0.13 0.25 0.38 0.50 0.63 0.76 0.88 1.00 1.14 1.26 1.39 1.51 1.64 1.77 1.89 2.02 2.15 2.27]
[14.9]
[29.8]
[44.8]
[59.7]
[74.6]
[89.5]
[104.5]
[119.4]
Flow (U.S. GPM) [l/s]
Grundfos Pump Performance Curves (Two Pumps)
Head (Feet) [kPa]
2 UP26-116 2UPS26-99 high spd 2 UPS26-99 med spd 2 UPS26-99 low spd
[0.13 0.25 0.38 0.50 0.63 0.76 0.88 1.00 1.14 1.26 1.39 1.51 1.64 1.77 1.89 2.02 2.15 2.27]
[29.8]
[59.7]
[89.5]
[119.4]
[149.3]
[179.1]
[208.9]
[238.8]
5 | Installaon, Operang, and Maintenance Manual
Flow Center sizing:
Performance curves
The specic NP Series ow center should be selected based on the system pressure drop (including the geo-
thermal heat pump, ground loop piping, and interior piping). Calculators to assist with pressure drop deter-
minaon and pump selecon are available at www.geo-o.com/calculators. The ow center selected should
provide at least the minimum amount of ow recommended by the heat pump manufacturer for the heat
pump selected.
NOTE: The NP Base (NPB) is currently oered with UPS26-99 and UP26-116 pumps only. NP, NPP, NPD, and
NPM ow centers have addional pump opons.

NPB Series Non-Pressurized Flow Centers | 6
Installaon
Mounng the unit
The NP Series ow center must be mounted on a level surface
near the ground source heat pump. The unit can be placed on
the oor or on an isolaon pad such as a small piece of expanded
polystyrene (blue board insulaon) or a high-density rubber equip-
ment pad. Since the cabinet is plasc and will not rust, an isolaon
pad is not required for a thermal break but may be used if desired.
An-p brackets and hardware are included and can be used if
deemed necessary for the installaon locaon. If these brackets
are used, several methods of aachment can be ulized. Figures
9a, 9b, and 9c show these methods. Note that if you chose to
mount the NP to a concrete oor, the concrete anchors must be
eld provided.
Figure 9c:
Figure 9b:
Figure 9a: An-p brackets (two included)
mounted on top sides of ow center
An-p brackets mounted on
boom of ow center
An-p brackets mounted on top
of ow center
Plumbing Opons
The NPB Series ow center can be plumbed with a wide variety
of materials including HDPE, PVC, copper, PEX, and exible hose
to provide many opons to the installer. The ow direcons to
and from the ow center are shown in Figure 10. The installer can
choose to direct the uid ow from the pump(s) to the geother-
mal heat pump out the top or the front of the ow center. The
included isolaon valve should be installed in the chosen direc-
on, and the included 1” plug should be installed in the unused
port. The brass swivel half-union ngs use a at gasket and
should be torqued hand-ght plus 1/8 to 1/4 turn onto the valves
and plug. Over torquing may cause the joint to leak. If the joint
drips at start-up, snug with channel locks unl the drip stops.
Figure 11 shows a standard installaon when the ground loop
headers are external to the building. Insulated 3-way ush valves
are available, or the installer may choose to install six ball valves
for ushing the loop and heat pump. Figure 12 shows an installa-
on where each loop circuit is brought into the mechanical room
and headered.
To HP
Opon 2
To HP
Opon 1
From
Loop
Figure 10: Flow Direcon

7 | Installaon, Operang, and Maintenance Manual
Figure 11: Plumbing diagram- external headers
Figure 12: Plumbing diagram- internal headers
Plumbing Opons: External Headers
Plumbing Opons: Internal Headers