4008 RV By-Pass Pump By SHURflo
Installation & Maintenance Manual

16GA [1,29mm] min.

Installation Preparation
CONNECTOR
The goal of installation is to provide a quiet, easyTypical Pump Installation
SWITCH
FUSE
FUSE
to-maintain installation with good flow and low
GROUND
backpressure. This can be accomplished with
the following guidelines:
• Mount on a solid surface in an accessible
location for strainer cleaning and pump maintenance.
SOLID SURFACE
• Use flexible high-pressure hose on the pump
POTABLE H20 INLET
inlet and outlet [such as SHURflo Kit 94-59100]. The pumps ports and strainer should not
HIGH-PRESSURE
STRAINER
be connected to plastic or rigid pipe, or the
FLEXIBLE HOSE
SWIVEL FITTINGS
pump's normal motion will transmit through
rigid plumbing causing noise, and possibly
Installation Guidelines
loosening or cracking components.
• Solid surface within 6 feet of tank
• Accessible location
• Pump must use an adequate 50-mesh strainer
• Minimize flow restrictions in the system • Strainer on pump inlet
[such as SHURflo 255 series strainers].
• No accumulator needed
• Properly sized wiring
• Use a minimum of 1/2" [13mm] Inner Diame• Flexible hose on inlet and outlet
• Proper electrical protection
ter plumbing. Smaller ID plumbing will cause
• Minimize plumbing elbows and valves
• Properly sized plumbing
cavitation, high backpressure, low flow and
noise.
• No need for an accumulator with by-pass pumps.
• Pump is designed for intermittent duty only: Do not use these pumps for running a Reverse-Osmosis [RO] Filtration
System. High pressure-continuous duty usage will shorten the life of the pump and is not covered under warranty.
• Wire Size is 16 GA MINIMUM , 12GA is recommended---See Wire Chart in Electrical Section for minimum sizing.
• Minimum power requirement is a 10 Amp circuit.
• Reduce restrictions on inlet and outlet. This includes small inner diameter shut-off valves, winterizing valves and
elbows.
• If the RV has an Intellitec Pump Controller, it must be rated at 10 or 15 amps; If the controller is rated at 7.5 Amps, a
new controller or a high-amp relay must be used.
Mounting
• Mount the pump within 6 feet of the tank for best performance and pump life. The pump will pull farther, but the farther it
pulls the more work it does, increasing vibration and noise, and reducing the output and pump life.
• Mount pump in a space of at least 1 cubic foot for adequate ventilation to prevent overheating.
• Pump may be mounted in any position.
• Mount pump for easy access for cleaning strainer, maintenance and service.
• Mount pump on a solid surface to prevent vibration and noise.
Electrical
• The pump works best on an individual filtered circuit, protected by the recommended fuse or breaker specified on the label.
• A 15-Amp switch is recommended and should be on the positive lead.
• Wire Sizing: Proper wire sizing is required for good pump operation. If the
wire is too small, low voltage will affect the pump performance and can create
a fire hazard.
SHUT OFF POWER TO THE PUMP WHEN LEAVING THE RV UNATTENDED.

Minimum Wire Size for a 10% voltage drop on a
12VDC, 10 Amp Circuit. Length is the distance from
the power source to pump and back to ground.
Feet

[Meters]

AWG

[mm²]

0 - 25

[0 - 7.6]

16

[1.3]

25 -50

[7.6 - 15.2]

14

[2.1]

50 - 70

[15.2 - 21.3]

12

[3.3]

70 -110 [21.3 - 33.5]

10

[5.3]
Plumbing
Installation of a strainer is required to prevent debris from entering the pump.
For noise and vibration reduction we recommend at least 18 in. [.5 M] of 1/2" [13mm] I.D. flexible high-pressure hose to
both ports. The pump ports and strainer should not be connected to plastic or rigid pipe. This hose should be anchored
where it meets the hard plumbing to reduce plumbing vibration.

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Operation
This pump is designed for intermittent duty only.
The pump operates normally up to about 40-psi, where a spring-loaded by-pass valve opens, allowing flow back from the
output side to the input side, providing smooth, steady flow with virtually no cycling, all the way down to a trickle. As a
faucet is opened back up, the pressure will drop, the by-pass will close and full flow is again obtained. This allows good
flow, even with today’s restrictive showers and pullout sprayer faucets. Performance will vary, of course, depending on the
voltage to the pump; lower voltage = lower flow, higher voltage = higher flow. Remember your electrical safety: It is
always best to shut power to the pump OFF when leaving the RV unattended.
About The By-Pass
NOTE: By-pass adjustment should be performed by professional technicians with proper
gauges and equipment.
The by-pass is a spring loaded diaphragm that opens up allowing water from the discharge side back to the inlet side.
The by-pass is set to begin opening at about 40 psi and creating full by-pass at about 62 psi (for 55 psi models), lower
pressure pumps will vary depending on the by-pass and pressure switch settings. If the switch or by -pass are adjusted too
much, the by-pass and switch shut-off can overlap and THE PUMP WILL NOT SHUT OFF. Screwing the switch screw in
clockwise will raise the shut-off pressure. Unscrewing the switch screw counterclockwise will lower the pump shut-off pressure. Screwing the by-pass screw in will raise the pressure at which the by-pass starts and raise the full by-pass pressure.
Unscrewing the by-pass screw counterclockwise will lower the pressure at which by-pass starts and lower the full by-pass
pressure. WARNING: If full by-pass is reached before the shut-off setting, the pump will not shut off. Full by-pass
pressure setting should be at least 5 psi higher than pump shut off pressure.
Maintenance
Normal pump maintenance is all that is needed: Checking and cleaning of the strainer, normal sanitizing and winterizing
and occasionally checking all plumbing hardware and fittings for tightness. Lack of sanitizing is the number one reason for
premature pump failure and poor performance over time. Lack of sanitizing will cause scale build-up on the diaphragm
and valves, causing low flow and leak back [occasional pump cycling with no faucets open or tank filling up when hooked
up to city water].
Sanitizing
Potable water systems require periodic maintenance to keep components working properly and deliver a consistent flow of
fresh water. Sanitizing is recommended: prior to storing, after a period of storage, or any time the system is opened or
contaminated, as follows: NOTE: Check your Vehicle Owner’s Manual for specific instructions. By-pass any filters
or remove filter cartridges.
1. Determine the amount of common household bleach needed to sanitize the tank.
A) 2 ounces of bleach per 15 gallons tank size: 60 gallon tank [15 x 4] = 4 x 2 ounces = 8 ounces of bleach.
B) I ml bleach per 1 liter tank size: 300 liter tank = 300 milliliters of bleach.
2. Mix the bleach with water in a container such as a gallon jug. If tank is filled through a pressurized fitting, pour the bleach
into the hose before attaching the hose to the city water entry.
3. Pour the bleach solution into the tank and fill the tank with potable water. Rock RV back and forth to coat top and sides of
potable water tank.
4. Open all faucets (Hot & Cold) allowing the water to run until the odor of chlorine is detected. Allow four (4) hours of
contact time to disinfect completely. Doubling the solution concentration allows for a contact time of one (1) hour.
5. Drain the tank. Refill the tank and flush the system once or twice until the odor has decreased. The residual chlorine
odor and taste is not harmful.
Winterizing Refer to the vehicle owner’s manual for specific winterizing instructions.
If water is allowed to freeze in the system, serious damage to the plumbing and pump may occur. Failures of this type will
void the warranty. The best guarantee against damage is to completely drain the pump and perform the following:
1. Drain the water tank. If the tank doesn't have a drain valve, open all faucets allowing the pump to operate until the tank
is empty.
2. Open all the faucets (including the lowest valve or drain in the plumbing), allow the pump to purge the water from the
plumbing, and then turn the pump OFF.
3. Using a pan to catch the remaining water, remove the plumbing at the pump's inlet/outlet ports. Turn the pump ON,
allowing it to operate until the water is expelled. Turn OFF power to the pump once the plumbing is emptied. Do not
reconnect the pump plumbing. Make a note at tank filler as a reminder: "Plumbing is disconnected".
4. All faucets must be left open to guard against any damage.
5. Potable anti-freeze may be poured down drains and toilets to protect p-traps and toilet seals. Sanitize the plumbing system
before putting the plumbing system back in service.

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Troubleshooting
Vibration induced by driving can loosen plumbing, strainers and pump hardware. Check for system
components that are loose. Also, refer to the chart below for trouble-shooting tips.
PUMP WILL NOT START/ BLOWS CIRCUIT:

•
•
•
•
•
•

PUMP WILL NOT SHUT-OFF / RUNS WHEN FAUCET IS CLOSED:

•

Electrical connections, fuse or breaker, main switch, and ground
connection.

•
•
•
•
•

Is the motor hot? Thermal breaker may have triggered; it will reset
when cool.
Is voltage present at the switch? Bypass the pressure switch.
Does the pump operate?
Charging System for correct voltage (±10%) and good ground.
For an open or grounded circuit, or motor; or improperly sized
wire.

•
•
•
•
•

•
•

For seized or locked diaphragm assembly (water frozen?).
Is the strainer clogged with debris?

•
•

Is there water in the tank, or has air collected in the hot water
heater?
Is the inlet tubing/plumbing sucking in air at plumbing connections
(vacuum leak)?

•
•
•

Is inlet/outlet plumbing severely restricted or kinked? Restrictive
valves?
Proper voltage with the pump operating (±10%).
For debris in pump inlet/outlet valves or swollen/dry valves.

•
•

For correct voltage to pump (±10%).
For loose drive assembly or pump head screws.
Are the valves held open by debris or is the rubber swollen?
Pressure switch operation. By -pass set higher than shut -off
For plumbing which may have vibrated loose.
For a restricted inlet (clogged strainer, kinked hose, restrictive
valves).
Is the pump plumbed with rigid pipe causing noise to transmit?
Does the mounting surface amplify noise (flexible)? Does it bang
like a drum?
For mounting feet that are loose or are compressed too tight.
For air in the system. Check all fixtures for air and bleed system.
The motor with pump head removed. Is noise from motor or pump
head?

LEAKS FROM PUMP HEAD OR SWITCH:

•
•
•

Pump housing for cracks or loose drive assembly screws.
RAPID CYCLING:

•

For air trapped in outlet side (water heater) or pump head.

NOISY OR ROUGH OPERATION:

WILL NOT PRIME/SPUTTERS: (No discharge/Motor runs)

•
•

Output side (pressure) plumbing for leaks, and inspect for leaky valves
or toilet.

For restrictive plumbing and flow restrictions in faucets/shower
heads.

For loose screws at switch, by -pass or pump head.
Switch diaphragm ruptured or pinched.
For punctured diaphragm if water is present in the drive

assembly.

Water filter/purifier should be on separate feed line.
Shut-off pressure set too low.

Typical Performance

55 psi models: part kits

4

No.
1

Component
Upper Assembly

Part Kit
94-800-00

2
3

Valve Assembly
2.5° Drive Assembly

94-800-01
94-800-02

4
N/S
1,2,3

Motor
Check Valve
Pump Head

11-302-00
94-800-03
94-800-04

N/S

Pressure Switch

PSI/Bar

GPM [LPM]

Amps

0/0

3.0 [11.3]

2.8

10/0.7

2.3 [8.7]

3.2

20/1.4

1.9 [7.2]

4.2

30/2.1

1.6 [6.0]

5.1

40/2.8

1.4 [5.3]

6.1

50/3.4

0.8 [3.0]

6.8

55/3.8

0

7.5

3
2
1

94-800-05

LIMITED WARRANTY
SHURflo warrants its aftermarket retail 4008 series potable water pumps to be free from material and workmanship defects under normal use and service for 2
years from the date of purchase with purchase receipt or 2 years from the date of manufacture indicated on the motor nameplate if no purchase receipt is
available, as outlined in document MS-030-152. Pumps installed as original equipment are warranted for 1 year, and fall under the warranty supplied by the
manufacturer, as outlined in document MS-030-123. This limited warranty is in lieu of all other warranties, expressed or implied (including without limitation
implied warranties of merchantability and fitness for a particular purpose), and no other person is authorized to give any other warranty or assume obligation or
liability on SHURflo's behalf. SHURflo shall not be liable for any labor, damage or other expense, nor shall SHURflo be liable f or any indirect, incidental or
consequential damages of any kind incurred by the use or sale of any defective Product or part. This limited warranty covers Products distributed within the
United States of America and Canada. Other world market areas should consult with the distributor for any deviation from this document. The limited warranty
will not apply to pumps that were improperly installed, misapplied, or are incompatible with components not manufactured by SHURflo. Product failure due to
foreign debris is not covered under the terms of this limited warranty. SHURflo will not warrant any Product that is physically damaged, or altered outside
SHURflo. Warranty claims may be resolved by an authorized dealer service center, or by a SHURflo service center. Returns are to be shipped with charges
pre-paid. Package all returns carefully. SHURflo will not be responsible for freight damage incurred during shipping to a service center. For complete Limited
Warranty details, consult SHURflo.

Visit our Web Site at http://www.shurflo.com
Shurflo reserves the right to update specifications,
change prices, or make substitutions without notice.

SHURflo
5900 Katella Avenue
Cypress, CA 90630
Phone (562) 795-5200
Toll Free (800) 854-3218
Fax (562) 795-7564

911-1008 Rev D
© 2009 SHURflo, LLC All Rights Reserved

SHURflo East
52748 Park Six Court
Elkhart, IN 46514-5427
Phone (562) 795-5200
Toll Free (800) 854-3218
Fax (574) 264-2169

SHURflo Europe, Middle East, Africa
Pentair Water Belgium bvba
Industriepark Wolfstee, Toekomstlann 30
B-2200 Herentals, Belgium
Phone +32-14-283500
Fax +32-14-283505

FLOW TECHNOLOLIES GROUP

5900 Katella Ave, Cypress, CA 90630
Phone (800) 854-3218 • (562) 795-5200 • Fax (562) 795-7564
www.shurflo.com

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