Pentair Myers MCU20S User manual

DOUBLE
INSULATED
NOTE! To the installer: Please make sure you provide this manual to the owner of the equipment or to the responsible
party who maintains the system.
MODEL MCU20S
CONDENSATE UNIT
INSTALLATION, OPERATING, SAFETY AND WARRANTY MANUAL
Part # 23833A463 | © 2012 Pentair Pump Group, Inc. | 11/08/12

23833A463 11/08/12 2
APPLICATION
The Myers Condensate Pump is designed to automatically
remove the liquid from an air conditioner evaporative coil and/or
a gas condensing warm air furnace. This pump is made from a
tough ABS plastic so it will resist corrosion and impacts.
CALIFORNIA PROPOSITION 65 WARNING:
This product and related accessories
contain chemicals known to the State of
California to cause cancer, birth defects or other
reproductive harm.
IMPORTANT SAFETY INSTALLATION
INSTRUCTIONS
n WARNING: To reduce the risk of electric shock,
connect switch leads to Class 2 circuit only.
n Pull plug before servicing this unit.
n FOR INDOOR USE ONLY
(Employer uniquement Al interior).
n Thermally protected (double insulated).
n Never handle the pump with wet hands or while standing in
or near damp ground, while the unit is plugged in.
n Never operate the pump with frayed or brittle power cord
and always protect it from sharp objects, hot surfaces, oil,
and chemicals.
n Avoid kinking the cord.
n Before installing or servicing your pump, be certain the
pump is not plugged in.
n THIS PUMP UNIT IS NOT SUBMERSIBLE.
SPECIFICATIONS
Motor Ratings: 115 VAC, 1.45 amps, 67 watts
Thermally protected
Double insulated enclosure
Weight: 3.25 lbs.
Dimension: 11" x 5" x 4-3/4"
Tank Capacity: 2 qts. total
Flow (GPH) Head (ft.)
95 1
85 5
70 10
45 15
0 20
UNPACK THE PUMP
Carefully unpack the unit. Check for damage and make sure
all of the required parts are included. The units are thoroughly
tested before packing to ensure safe delivery and operation. If
there is any sign of damage due to shipment, return it to the
place of purchase for repair or replacement.
INSTALLATION
1. Choose a mounting location near the air conditioner or
furnace. The pump must be mounted level and the inlet
must be below the lowest drain. The unit has two brackets
built into the deck that can be used to attach the unit to a
wall or to the side of the appliance with installer supplied
fasteners.
2. The pump should be mounted so the deck is at least 6½"
above the floor. This will allow clearance for the tank to be
removed later for cleaning.
CONNECTING THE PIPING
1. Run flexible tubing or pipe from the condensate drain on the
evaporator pan and/or drain from furnace to one of the inlet
holes on the pump. (Note: This drain line should have a
continuous downward slope to allow gravity flow.)
2. Cut the end of the line at an angle so the end does not
close off on the bottom of the pump tank. Note: If there
is an overflow drain from the evaporator pan or from the
furnace, it may be necessary to tee the overflow and the
main drain together before they enter the pump.
3. Connect a discharge line to the barbed check valve on top
of the pump. This line may be flexible tubing or rigid pipe,
but must be no larger than 3/8" I.D.
4. Extend the discharge line straight up from the pump to the
highest point possible without exceeding the head/GPH
capacity of the pump before directing the line to the drain.
From this high point, run the discharge line to a drain with a
downward slope.
5. For best results, the drain should be below or approximately
level with the bottom of the pump tank. If it is not possible
to slope the line downward, make an inverted “U” trap at
the high point of the discharge line above the pump.
WARNING: Although not needed for this pump, local codes
may require the use of a condensate neutralizer when using
this pump with a condensing gas furnace. Consult local
codes for guidelines.
ELECTRICAL ASSEMBLY
n Shut off electrical power at the fuse box before making
any wiring connections. All wiring must be done
according to local and/or applicable national codes.
TEE COIL
DRAINS
TOGETHER IF
NECESSARY
CONNECTION FOR
DISCHARGE LINE
OVERFLOW DRAIN FROM
FURNACE
CONDENSATE NEUTRALIZER
CARTRIDGE (IF REQUIRED)
MAIN
DRAIN FROM FURNACE
MAIN DRAIN
FROM COIL
OVERFLOW DRAIN
FROM COIL WHEN
REQUIRED
CONDENSING
GAS FURNACE
20 FT.
MAX.
CONDENSATE
PUMP
DRAIN
LINE
AIR CONDITIONING
EVAPORATOR
3/8 VINYL TUBING

23833A463 11/08/12
3
NOTE: The stripped white wires extending from the side
of the top housing are NOT powered.
These are used in Step 2.
1. Main Power: Unit is provided with a 6 foot long power
cord. Connect this cord to a constant line voltage source,
not a fan or other device that may run intermittently.
2. Safety Switch: The
overflow safety switch may
be wired in series with the
appliance’s thermostat to
shut off the unit in the event
that the pump fails. In
the case where heating or
cooling requirements are
a necessity, the overflow
safety switch may be wired
into an alarm circuit. Note:
In most cases, use the normally closed (NC) contacts when
used with a furnace or air conditioner and use the normally
open (NO) contacts when used to trigger an alarm.
TEST PROCEDURES
1. With the unit plugged in and the discharge line in place,
pour water into the pump reservoir until the unit activates to
verify the unit works.
2. To test the overflow safety circuit
a. Energize the appliance so it runs.
b. Kink the tube coming from the pump discharge, or
unplug the power cord, so it cannot pump out.
c. Pour water into the pump reservoir, filling it completely.
d. As the water level nears the top of the unit the overflow
safety switch should activate, breaking the thermostat
circuit to the appliance (or triggering an alarm circuit,
if used).
e. Unkink the tube, or plug the cord back in, and allow
the pump to empty the tank. As the water level goes
down the overflow safety switch will deactivate and the
appliance will energize again (or the alarm will reset).
MAINTENANCE
WARNING! Before attempting any maintenance on the unit,
disconnect the power cord from the power supply to reduce
the risk of electric shock. Also, take whatever precautions
are necessary if the safety overflow switch is wired to a
thermostat or alarm circuit.
Servicing a double-insulated product should be done only by
qualified service personnel.
If the unit does not perform as stated in the above tests,
remove the two screws holding the cover from the deck and
remove the cover. Verify that the float mechanism moves up
and down freely. If the float binds, it may be dirty or damaged.
Since the motor is totally enclosed, no maintenance is required
on the motor. However, the tank and float may need to be
cleaned periodically. Simply remove the four screws at the
corners of the pump deck and lower the tank. The tank can
now be cleaned with a mild detergent. Use a damp cloth to
wipe off the float if necessary. The impeller may need to be
cleaned as well.
OVERFLOW SAFE-
TY SWITCH
TYPICAL
THERMOSTAT
THERMOSTAT
TERMINAL
CONNECTIONS
IN FURNACE
TROUBLESHOOTING
If the unit does not function properly, refer to the following:
Unit does not run.
Pump makes loud noises
when running.
Unit runs but does not pump
liquid out.
Liquid drains back into pump from
discharge line.
Liquid leaks from around the
check valve.
a. Check the power supply.
b. Check the appliance to see if condensation is actually being generated.
c. Check to make sure the pump float mechanism moves freely and clicks the
activation switch when moved up and down.
d. The motor is protected by a thermal overload device, which may have tripped.
This may be verified by measuring the resistance through the motor coil. An
open circuit reading indicates that the motor has overloaded, and the unit must
be replaced.
e. Check the drain line(s) into the pump for obstructions. Note: If these lines are
clogged and remain clogged, the appliance may eventually be damaged.
a. Check the tank for debris and clean if necessary. The impeller may also
be cleaned.
a. Check the activation float to be sure it is not stuck in the up position.
b. Check the height of the discharge tubing to be sure it does not exceed 20
vertical feet.
c. Check the discharge tube for obstructions and clear if needed.
d. Check the check valve for obstructions.
a. Check valve may have debris in it.
b. If the discharge line is plumbed so the highest point is less than 5 feet above the
pump, the check valve may allow liquid to drain out of the line. This is normal
and will not damage the pump.
a. If the check valve is too tight or too loose it may leak around the O-ring.
Check that the valve is hand tight, then tighten an additional 1/2 turn with
9/16" wrench.
b. If the O-ring under the check valve is damaged, replace with a 1/2" I.D. x 11/16"
O.D. x 3/32" width O-ring, or purchase a replacement check valve, which
includes an O-ring.

Warranty Rev. 12/13
STANDARD LIMITED WARRANTY
Pentair Myers® warrants its products against defects in material and workmanship for a period of 12 months from the
date of shipment from Pentair Myers or 18 months from the manufacturing date, whichever occurs first – provided
that such products are used in compliance with the requirements of the Pentair Myers catalog and technical manuals
for use in pumping raw sewage, municipal wastewater or similar, abrasive-free, noncorrosive liquids.
During the warranty period and subject to the conditions set forth, Pentair Myers, at its discretion, will repair or
replace to the original user, the parts that prove defective in materials and workmanship. Pentair Myers reserves the
right to change or improve its products or any portions thereof without being obligated to provide such a change or
improvement for prior sold and/or shipped units.
Start-up reports and electrical schematics may be required to support warranty claims. Submit at the time of start-
up through the Pentair Myers website: http://forms.pentairliterature.com/startupform/startupform.asp?type=m.
Warranty is effective only if Pentair Myers authorized control panels are used. All seal fail and heat sensing devices
must be hooked up, functional and monitored or this warranty will be void. Pentair Myers will cover only the lower
seal and labor thereof for all dual seal pumps. Under no circumstance will Pentair Myers be responsible for the cost
of field labor, travel expenses, rented equipment, removal/reinstallation costs or freight expenses to and from the
factory or an authorized Pentair Myers service facility.
This limited warranty will not apply: (a) to defects or malfunctions resulting from failure to properly install, operate or
maintain the unit in accordance with the printed instructions provided; (b) to failures resulting from abuse, accident
or negligence; (c) to normal maintenance services and parts used in connection with such service; (d) to units that
are not installed in accordance with applicable local codes, ordinances and good trade practices; (e) if the unit is
moved from its original installation location; (f) if unit is used for purposes other than for what it is designed and
manufactured; (g) to any unit that has been repaired or altered by anyone other than Pentair Myers or an authorized
Pentair Myers service provider; (h) to any unit that has been repaired using non factory specified/OEM parts.
Warranty Exclusions: PENTAIR MYERS MAKES NO EXPRESS OR IMPLIED WARRANTIES THAT EXTEND BEYOND
THE DESCRIPTION ON THE FACE HEREOF. PENTAIR MYERS SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR ANY PARTICULAR PURPOSE.
Liability Limitation: IN NO EVENT SHALL PENTAIR MYERS BE LIABLE OR RESPONSIBLE FOR CONSEQUENTIAL,
INCIDENTAL OR SPECIAL DAMAGES RESULTING FROM OR RELATED IN ANY MANNER TO ANY PENTAIR MYERS
PRODUCT OR PARTS THEREOF. PERSONAL INJURY AND/OR PROPERTY DAMAGE MAY RESULT FROM IMPROPER
INSTALLATION. PENTAIR MYERS DISCLAIMS ALL LIABILITY, INCLUDING LIABILITY UNDER THIS WARRANTY, FOR
IMPROPER INSTALLATION. PENTAIR MYERS RECOMMENDS INSTALLATION BY PROFESSIONALS.
Some states do not permit some or all of the above warranty limitations or the exclusion or limitation of incidental or
consequential damages and therefore such limitations may not apply to you. No warranties or representations at any
time made by any representatives of Pentair Myers shall vary or expand the provision hereof.
1101 MYERS PARKWAY 490 PINEBUSH ROAD, UNIT 4
ASHLAND, OHIO 44805 CAMBRIDGE, ONTARIO, CANADA N1T 0A5
PH: 855-274-8947 PH: 800-363-7867
WWW.FEMYERS.COM WWW.FEMYERS.COM