Master Water Conditioning MWC-EM Series User manual

MWC-EM Series Ultraviolet Sterilizers
MWC-EM7 / MWC-EM10 / MWC-EM20
Installation and Operation Manual
2022 VERSION

Table of Contents
Page
Topic
Description
1
Model #
Model Number
Caution
Looking at UV Light
Shipping Description
UV Packaging
2
Piping Layout
Piping Layout
Specification Table
Unit Specifications
3
Pre-Treatment
Pre-treatment Discussed
Water Quality Table
Unit Location
Unit Set Up
4
MWC-EM Pressure Vessel
Pressure Vessel Installation
5
UV Sensor
Sensor Installation
6
Electrical
Electrical Requirements
MWC Meter Power Supply
Meter/Power Supply
Installation
7
Grounding
Grounding Instructions
8
Quartz and O’ring
Installing Quartz and O’ring
Germicidal Lamp
Installing Germicidal Lamp
MWC-EM Meter
Starting up MWC-EM Meter
9
Water Pressure Test
Filling Vessel with water
Disinfecting
Instructions for disinfecting
the Piping System
10
Final Check
Installation Final Check
Intensity Adjustment
Adjusting Intensity
11
Annual Maintenance
Germicidal Lamp, Quartz
Sleeve, Sensor Eye
Maintenance
Figure 2
Figure 2
12
Troubleshooting
Troubleshooting
13
Replacement Parts
Replacement Parts
14
Warranty
Warranty

Installation and Operating Instructions
for MWC-EM Series Ultraviolet Sterilizers
Model #:
_______ MWC-EM7 7 gpm UV- ¾”
_______ MWC-EM10 10 gpm UV -¾”
_______ MWC-EM20 20 gpm UV -1”
CAUTION:
NEVER LOOK DIRECTLY AT THE ULTRAVIOLET LIGHT WITH
THE NAKED EYE. View through a piece of ordinary glass or optical
glasses. ULTRAVIOLET LIGHT may cause eye irritation if eye is not
properly protected. You should never have to look directly at the
ULTRAVIOLET LIGHT when installing or trouble-shooting one of our
MWC-EM Water Sterilizers.
Shipping Description:
The UV unit is shipped complete as follows:
The large box contains the UV vessel and inside that box you will
also find the following:
1. A box containing the gland nut, quartz o’ring, silicone, and UV
brackets w/grounding lug.
2. A box containing the metered power supply with grounding wire
attached.
3. A box containing either the (1) N/C ¾” SS or (1) N/C 1”SS
normally closed solenoid.
4. A tube containing the germicidal lamp.
5. A tube containing the quartz sleeve.
FEATURE:
The UV meter has a built in safety feature that will de- energize
the normally closed solenoid and shut off the water if lamp goes out
or if the water quality changes!

Pre-Treatment:
A complete water test is recommended to determine if pre-treatment
equipment is required before installation of the UV unit. Water must
meet criteria below:
Contaminant
Maximum Allowable Level
Chloride
250 ppm
Color
None
Hardness
8 gpg
Iron
0.3 ppm
Manganese
0.05 ppm
pH
Range between 6 and 8.5
Total Dissolved Solids (TDS)
500 ppm
Turbidity
5 ntu
If untreated water quality exceeds the maximum allowable levels
specified, this will result in bacteria passing through the UV unit
and into the piping system.
Unit Location:
1. The MWC-EM unit must be installed after the well tank and any
water pre-treatment equipment (softeners, filter, etc.). You must
install a Cartridge type Dirt Filter before the MWC-EM unit to
eliminate the possibility of a dirt build-up inside the stainless
steel sterilization chamber. (SEE PAGE 2, PIPING LAYOUT )
2. Install at least 4 feet from a dedicated electrical outlet.
DO NOT INSTALL NEAR ANY HEATING SYSTEMS WHICH
RAISE THE AIR TEMPERATURE OVER 100 DEGREES.

MWC-EM Solenoid and 304 Electro Polished SS Vessel
Installation:
1. The ultraviolet unit is designed to be installed in a vertical position.
The unit is supplied with (2) brackets to support the unit.
NOTE: The upper bracket has a grounding lug attached to it
2. Place the top bracket (larger one) over the nipple located at the
top of the vessel. The end of the bracket with the three holes
should be facing up towards the top of the vessel.
3. Tighten the gray PVC ring onto the nipple. This will compress
down onto the top of bracket.
4. Attach the smaller bracket to the bottom of the vessel. The
bracket has a clip type fastener that attaches to the bottom rim of
the vessel. The end of the bracket with the three holes should be
facing down towards the bottom of the vessel.
5. Secure the top bracket to a wall by using three appropriate screws
or fasteners (not provided).
Be sure to leave plenty of clearance above vessel for servicing
the quartz tube and germicidal lamp. (For proper clearance, see
Specification Table on page 2)
6. Secure the bottom bracket to the wall by using three screws or
fasteners (not provided).
7. Use quality unions and ball valves on the inlet and outlet for
servicing the unit. See Page 2for a typical installation piping
layout. If sweat fittings are used, be sure soldering is done in such
a manner as not to allow heat to reach the UV vessel. If Schedule
80 PVC or CPVC is used, make sure to follow the proper primer
and solvent instructions.
8. Pipe the inlet into the bottom nipple of the UV vessel.
9. Install a 1’’ x 3/4” reducing bushing (not provided) into the inlet of
the solenoid valve.
10. Install the ¾” (for the EM7 and EM10 units) or the 1” (for the
EM20 units) normally closed solenoid to the outlet on the top
nipple of the UV vessel. Make sure that the solenoid is installed in
the proper direction. See page 2 There is an internal flow
restrictor in the outlet nipple of all units. It is recommended you
install a boiler drain on the inlet piping of the unit. This will
allow for easy draining of the vessel when replacing the UV
quartz.

UV Sensor Installation:
1. First, unwrap the sensor carefully. Being very careful not to
drop or break the sensor eyepiece.
2. Wipe the sensor eyepiece with household alcohol to remove
dirt, oil and fingerprints.
3. Before inserting the UV sensor into the vessel check the o’ring
this is on the quartz eyepiece.
4. Insert the UV sensor assembly with gray gland nut. Hand
tighten only!
5. Attach the other end of the UV sensors black amp electrical
connection to the lower right side of the meter. Insert the amp
into the twist lock connector. The connector will only fit into the
connector one way. Hand Tighten Only!
UV Sensor Assembly
Quartz Dome
Eyepiece
UV Sensor Cell
Black Grommet
Gray Sensor Cord
Gray Quartz Nut with O'ring
Figure 1
O-ring

Electrical Requirements:
Always follow all local electrical codes when installing our
water
treatment equipment.
1. Provide an 115v/60Hz properly grounded dedicated electrical
outlet. (It’s very important that the polarity be correct)
Avoid using outlets that are switch controlled.
2. Maximum amperage required is 5 amps.
3. Make sure the electrical service provides power 24 hours per day.
We recommend installing a surge protector to protect unit from
power surges, which are not covered by warranty.
!!! DO NOT UNDER ANY CIRCUMSTANCE WIRE THE UV UNIT TO THE
WELL PUMP SWITCH OR WELL PUMP ELECTRICAL SUPPLY!!!
Meter & Power Supply Installation:
1. Choose a wall placement that is dry and clear of all piping and
metal objects, and within 4 feet of the UV vessel and the
electrical outlet.
2. Remove cover from power supply for mounting.
3. Secure power supply to wall with screws (not provided).
SEE PROPER GROUNDING INSTRUCTIONS ON NEXT PAGE

MASTER
Water Conditioning Corp.
MWC-SERIES GROUNDING INSTRUCTIONS
IMPORTANT
All MWC-Series UV systems must be properly grounded. The vessel must be grounded
to the MWC-Power Supply to make a complete ground.
MWC-SERIES
Grounding Lug Installation
Grounding Lug
Front View of Bracket
Insert stripped green ground wire into ground
lug
and hand tighten with screw driver.
Top View of Bracket
14 gauge green ground
wire from power supply

Quartz and O’ring Installation:
1. Wipe the quartz sleeve with household alcohol to remove dirt, oil
and fingerprints.
2. Carefully place the quartz sleeve into the top opening of the
vessel.
3. Lubricate the o'ring with silicone (which is supplied) then place the
o’ring over the top of the quartz sleeve.
4. Hand-tighten the clear gland nut onto the nipple located on the top
of the vessel. Do not over tighten or the quartz sleeve may
shatter.
When operating, the clear gland nut will glow blue.
Germicidal Lamp Installation:
1. Clean the germicidal lamp with household alcohol to remove dirt,
oil and fingerprints.
2. Remove jumper wire from white-end connection of power supply
and insert UV lamp pins in place of jumper wire.
3. Gently insert the germicidal lamp into the quartz sleeve through
the center of the clear gland nut located at the top of the vessel. Be
careful not to drop the lamp inside the vessel. This could break the
quartz sleeve.
4. Slide the black fitting into the center of the clear gland nut.
Meter and Power Supply Start Up:
1. Before plugging the UV meter power supply into the electrical
outlet. Locate the on/off switch on the lower left side of the meter
and flip switch to the off position
2. Re-install cover.
3. Plug the meter into the surge protector (not provided) then
into dedicated electrical outlet.
4. Turn the UV meter power supply to the on position. The MWC-EM unit
will alarm immediately until the reading on the UV meter reaches
100%. Once it reaches the 100% it will continue to alarm until the time
delay times out which could take several minutes.
5. Once the alarm goes off, the system is ready for the next step.

Filling the UV Unit with Water:
NOTE: Plug the 1” normally closed solenoid into a dedicated
electrical supply. This is only during the filling and disinfection
of the piping!
1. Open the inlet ball valve about 25% to fill the UV vessel slowly.
2. Open the inlet and outlet ball valve to their full open position.
3. Open cold water faucet in kitchen and run until all air is purged.
Shut off faucet.
4. Inspect for leaks and repair if any are found.
Disinfecting the Piping System with Chlorine:
NOTE: The MWC-EM meter will drop from a 100% and start to
alarm once the chlorine is induced into the system! This is
common and is caused by the reaction when chlorine and
water are mixed and the UV meter eye senses interference in
the UV vessel.
1. Shut off the water to the inlet and outlet of the cartridge filter.
2. Remove the cartridge sump and empty all water. Fill with
household chlorine (Clorox, non-scented), 5.25% sodium
hypochlorite.
3. Re-install the sump to the filter assembly and open the inlet and
outlet valves.
4. Open the cold water faucet at the furthest point in the piping until
you detect chlorine odor. Once the odor is detected, close that
faucet. Continue this procedure until the chlorine odor has been
detected at every faucet. If chlorine odor is not detected at all
faucets, repeat steps 1 through 4.
5. Close ball valve on outlet of cartridge filter.
6. Allow the water to stand for at least (4) hours to kill the bacteria
residual in the piping system.
7. Unplug solenoid from outlet and plug into the lower right side of
the MWC-EM Meter Power Supply.
** No water should be used during disinfection. **

Final Check:
1. Open outlet ball valve on UV unit.
2. Make sure the MWC-EM UV Unit is plugged into a surge protector
(not provided) then a dedicated electrical outlet with power 24
hours per day.
3. Check all piping for leaks, repair if necessary.
4. Unplug the 1” normally closed solenoid from the electrical outlet
and plug the solenoid into the lower right side of the UV Meter
Supply.
5. Open cold water lines and flush out until chlorine odor is no longer
detected.
Before consumption of water, an EPA Lab
Test is suggested.

MWC-EM UV INTENSITY ADJUSTMENT:
1. Once the unit has been in operation it maybe necessary to reset
the UV meter to 100%.
NOTE: All MWC-EM units are tested and calibrated at the factory.
2. The MWC-EM meter is very sensitive to the water quality and
room temperature!
3. When resetting the meter to 100%, unit must be running for
minimum of 1 hour.
4. You will need a very small flat head screw driver. Remove the
black cap located on the upper right side of the meter
5. With the unit on and operating turn the lower screw clock wise ¼
turn at time until you reach 100%. The MWC-EM unit is now
working properly, you may now re-install the black cap.
NOTE: Never adjust or turn the upper screw on the meter board!
This has been set at the factory and cannot be field adjusted! If it
is changed it must be sent back to the factory for recalibration!
UV Meter Adjustment
Set at 100%
Mounting Holes
UV sensor amp connection
1” N/C solenoid connection
Fuse 1.5 amps
Mounting Holes
ON/OFF Switch

ANNUAL MAINTENANCE PROCEDURE:
Annual Germicidal Lamp Replacement and Quartz Cleaning:
1. Unplug the UV Meter power supply from surge protector and the
electrical outlet.
2. Open the ball valve/test port on outlet side of UV unit to
depressurize vessel. When completed, close ball valve/test port.
3. Pull the black cap from the center of the clear gland nut.
4. Carefully lift the germicidal lamp out of the quartz sleeve by pulling
up on the gray harness wire and discard the lamp. Remember the
lamp is glass and can cause injury to you if the lamp is dropped.
5. Open the ball valve/test port on outlet side of UV unit to
depressurize vessel. When completed, close ball valve/test port.
6. Carefully remove clear gland nut, gently grasp quartz sleeve and
lift out.
7. Remove clear gland nut and O-ring from quartz sleeve.
8. Clean quartz sleeve with household alcohol. If stained, replace.
(Reference Quartz Installation)
9. Follow with germicidal lamp installation Remove the UV meter eye
and clean with household alcohol and reinstall.
MWC-EM SERIES

TROUBLESHOOTING
Symptom: No flow of water no Alarm and Gland Nut not glowing
Cause Solution
Electric Supply
Check electrical outlet and breaker box for power.
Replace fuse in Meter Power Supply
Symptom: No flow of water no Alarm and Gland Nut is glowing
blue and meter is reading 100%
Cause Solution
Solenoid
Turn off water and release pressure to the MWC-EM
unit. Remove solenoid coil and clean port and plunger.
Defective solenoid replace
Symptom: Alarm is on and no flow of water and Meter is reading
less than 50% and Lamp is on and Gland Nut is glowing blue.
Cause Solution
Lamp is over a year old
Replace lamp
See Germicidal Lamp Replacement.
Quartz Sleeve is dirty
Remove quartz sleeve and clean
UV sensor eye dirty
Remove Sensor Eye and clean
Symptom: Alarm is on and no flow of water and Lamp is out and
Meter is reading 0%
Cause Solution
Lamp
Replace lamp
See Germicidal Lamp Replacement.
Remove quartz sleeve and clean
Remove Sensor Eye and clean
MWC-EM power supply defective replace

4 YEAR LIMITED WARRANTY
As of November 2022
This MWC-E, ES & EM Series Ultraviolet Sterilizer is warranted for a period of four years
from date of purchase by first user against defects in materials and workmanship, except for the
Ultraviolet Lamp which is warranted for 90 days and a UV Meter Eyepiece Assembly which is
warranted for one year from date of purchase against defects in materials and workmanship.
Except, as specifically set forth in this paragraph, Master Water Conditioning Corporation makes no
other warranties, express or implied.
This warranty shall be void if the ultraviolet sterilizer is moved from the place of original
installation, or if damage is caused by misuse, misapplication, accident, freezing, flood, fire or if not
installed in accordance with instructions furnished by Master Water Conditioning Corporation.
This warranty shall be void in the event of damages from external sources or where the
ultraviolet sterilizer has been operated at pressure in excess of 100 pounds per square inch or at a
temperature in excess of 100 degrees F., or below 32 degrees F. Incidental costs or consequential
damages are not covered by this warranty.
All defective parts shall be returned prepaid to Master Water Conditioning Corporation for
inspection. Master shall not be liable for labor charges other than Master factory repairs.
This warranty gives you specific legal rights, and you may have other rights which vary from
state to state. Some states do not allow limitations on duration of implied warranties or exclusion of
incidental or consequential damages, so the above limitations may not apply to you.
All claims must be submitted in writing to Master Water Conditioning Corporation at 224
Shoemaker Road, Pottstown, Pennsylvania 19464, within thirty (30) days from the discovery of the
defect. Master Water Conditioning Corporation thereafter will correct defective parts and
workmanship or rusting, corrosion or bursting within sixty (60) days.
224 Shoemaker Rd. Pottstown, Pa. 19464
MASTER
Water Conditioning Corp.

MWC-EM UV INTENSITY ADJUSTMENT:
1. Once the unit has been in operation it maybe necessary to reset
the UV meter to 100%.
NOTE: All MWC-EM units are tested and calibrated at the factory.
2. The MWC-EM meter is very sensitive to the water quality and
room temperature!
3. When resetting the meter to 100%, unit must be running for
minimum of 1 hour.
4. You will need a very small flat head screw driver. Remove the
black cap located on the upper right side of the meter
5. With the unit on and operating turn the lower screw clock wise ¼
turn at time until you reach 100%. The MWC-EM unit is now
working properly, you may now re-install the black cap.
NOTE: Never adjust or turn the upper screw on the meter board!
This has been set at the factory and cannot be field adjusted! If it
is changed it must be sent back to the factory for recalibration!
UV Meter Adjustment
Set at 100%
Mounting Holes
UV sensor amp connection
1” N/C solenoid connection
Fuse 1.5 amps
Mounting Holes
ON/OFF Switch

UV Sensor Installation:
1. First, unwrap the sensor carefully. Being very careful not to
drop or break the sensor eyepiece.
2. Wipe the sensor eyepiece with household alcohol to remove
dirt, oil and fingerprints.
3. Before inserting the UV sensor into the vessel check the o’ring
this is on the quartz eyepiece.
4. Insert the UV sensor assembly with gray gland nut. Hand
tighten only!
5. Attach the other end of the UV sensors black amp electrical
connection to the lower right side of the meter. Insert the amp
into the twist lock connector. The connector will only fit into the
connector one way. Hand Tighten Only!
UV Sensor Assembly
Quartz Dome
Eyepiece
UV Sensor Cell
Black Grommet
Gray Sensor Cord
Gray Quartz Nut with O'ring
Figure 1
O-ring
CAUTION:
NEVER LOOK DIRECTLY AT THE ULTRAVIOLET LIGHT WITH
THE NAKED EYE. View through a piece of ordinary glass or optical
glasses. ULTRAVIOLET LIGHT may cause eye irritation if eye is not
properly protected. You should never have to look directly at the
ULTRAVIOLET LIGHT when installing or trouble-shooting one of our
MWC-EM Water Sterilizers.

MWC-EM FACTS SHEET
IMPORTANT
GROUNDING INSTRUCTIONS
All MWC-SERIES UV Systems must be grounded! The green 14# copper wire
coming out of the power supply must be grounded to the UV Vessel! Attach the
copper wire to the grounding lug to the upper mounting bracket and tighten the
screw.
CAUTION:
NEVER LOOK DIRECTLY AT THE ULTRAVIOLET LIGHT WITH THE NAKED EYE. View through a
piece of ordinary glass or optical glasses. ULTRAVIOLET LIGHT may cause eye irritation if eye is not
properly protected. You should never have to look directly at the ULTRAVIOLET LIGHT when installing
or trouble-shooting one of our MWC-E Water Sterilizers.
Pre-Treatment:
A complete water test is recommended to determine if pre-treatment equipment is required before
installation of the UV unit. Water must meet criteria below:
Untreated Water Quality Maximum Allowable Level
Chloride 250.00 ppm
Color 0.00 units
Hardness 8.00 gpg
Iron 0.30 ppm
Manganese 0.05 ppm
pH 6.0 to 8.5
Total Dissolved Solids 500.00 ppm
Turbidity 5.00 ntu
If untreated water quality exceeds the maximum allowable levels specified, this will result in
bacteria passing through the UV unit and into the piping system.
Unit Location:
1. The MWC-EM unit must be installed after the well tank and any
water pre-treatment equipment (softeners, filter, etc.). You must
install a Cartridge type Dirt Filter before the MWC-E unit to
eliminate the possibility of a dirt build-up inside the stainless
steel sterilization chamber. (SEE PAGE 2, PIPING LAYOUT)
2. Install at least 4 feet from a dedicated electrical outlet.
DO NOT INSTALL NEAR ANY HEATING SYSTEMS WHICH RAISE
THE AIR TEMPERATURE OVER 100 DEGREES.

Disinfecting the Piping System with Chlorine:
1. Shut off the water to the inlet and outlet of the cartridge filter.
2. Remove the cartridge sump and empty all water. Fill with household chlorine (Clorox, non-
scented), 5.25% sodium hypochlorite.
3. Re-install the sump to the filter assembly and open the inlet and outlet valves.
4. Open the cold water faucet at the farthest point in the piping until you detect chlorine odor.
Once the odor is detected, close that faucet. Continue this procedure until the chlorine odor
has been detected at every faucet. If chlorine odor is not detected at all faucets, repeat
steps 1 through 4.
5. Close ball valve on outlet of cartridge filter.
6. Allow the water to stand for at least (4) hours to kill the bacteria residual in the piping
system.
** No water should be used during disinfection. **
Before consumption of water, an EPA Lab Test is suggested.
MWC-EM SERIES
TROUBLESHOOTING
Symptom: No flow of water no Alarm and Gland Nut not glowing
Cause
Solution
Electric Supply
Check electrical outlet and breaker box for power.
Replace fuse in Meter Power Supply
Symptom: No flow of water no Alarm and Gland Nut is glowing blue and meter is reading 100%
Cause
Solution
Solenoid
Turn off water and release pressure to the MWC-EM unit.
Remove solenoid coil and clean port and plunger.
Defective solenoid replace
Symptom: Alarm is on and no flow of water and Meter is reading less than 50% and Lamp is on
and Gland Nut is glowing blue.
Cause
Solution
Lamp is over a year old
Replace lamp
See Germicidal Lamp Replacement.
Quartz Sleeve is dirty
Remove quartz sleeve and
UV quartz eye dirty
Remove Quartz Eye and clean
Symptom: Alarm is on and no flow of water and Lamp is out and Meter is reading 0%
Cause
Solution
Lamp
Replace lamp
See Germicidal Lamp Replacement.
Remove quartz sleeve and clean
Remove Quartz Eye and clean