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MODEL MVA (34A SERIES)
THERMOSTATIC MIXING VALVE
INSTALLATION
1. Unit must be installed by a licensed plumber in accordance with these instructions and state and local plumbing codes.
2. Flush all piping thoroughly before installation.
3. Mount the unit so that it is accessible for adjustment, cleaning and service.
4. Adequate mounting support is recommended.
5. The unit can be installed in any orientation. Make sure that cold water supply be connected to port "C", hot water supply to port "H", and mixed water
discharge to port "M".
6. Cure times for CPVC joints shall be as recommended by the adhesive manufacture or 1 hour minimum, whichever is longer. Exposure to temperatures above
100 °F may require extended curing times.
TYPICAL INSTALLATION - NO RECIRCULATION SYSTEM
COLD WATER
INLET
OPERATION
The Apollo "MVA" Series uses a shuttle/piston to control the volumes of cold and hot water required to deliver water at a predetermined temperature. Cold water
enters the mixing chamber above the top face of the shuttle, and hot water enters below the lower face of the shuttle. The thermostatic element which is positioned
in the mixing chamber, is connected to the spring-loaded shuttle, which moves up and down in response to expansion and contraction of the element.
In the event of an increase in the temperature of either the hot or cold water supply, as the change commences to alter the temperature of the water in the mixing
chamber, the thermostatic element immediately reacts by expanding. This expansion moves the shuttle downward decreasing the opening area of the hot water
supply, and increasing the opening for the cold water. This change in the volumes of the respective water supplies in the correct proportions, compensates for the
change of temperature of the water in the mixing chamber, and a constant mixed water is maintained. The sensitivity of the thermostatic element ensures
UNION NUT
TAILPIECE
STRAINER
INLET
CHECK VALVE
INSTALLATION, OPERATION, & MAINTENANCE INSTRUCTIONS
TYPICAL INSTALLATION - WITH RECIRCULATION SYSTEM
HIGH TEMP.
FIXTURES
AQUASTAT
HEAT
SOURCE
BOILER,
WATER
HEATER,
ETC.
HC
MVA
H C
M
MIX TEMP
FIXTURES
HANDLE SCREW
HANDLE
ADJUSTMENT
STEM
STEM RETAINER
SHUTTLE O-RING
SHUTTLE/PISTON
THERMOSTATIC ELEMENT
SPRING
BODY
COLD WATER
INLET
- FLOW DIRECTION
- THERMAL EXPANSION
RELIEF VALVE OR TANK
- PRV
- CHECK VLAVE
- BALANCING VALVE
- CIRCULATOR
- TEMPERATURE GAUGE
TAILPIECE
STRAINER
INLET
CHECK VALVE
MVA
H C
HC
HEAT
SOURCE
BOILER,
WATER
HEATER,
ETC.
instantaneous movement of expansion and contraction as necessary. In the
event of complete failure of the cold water supply, the ensuing expansion of
the element shuts-off the hot water supply completely.
RECIRCULATION
LOOP
M
ADJUSTMENT
For optimum performance it is imperative that the hot water inlet temperature
has a minimum of 15°F above the desired outlet temperature.
1) After the unit is completely installed, turn on the cold water supply, then hot
water supply. It is recommended to open the cold side first to avoid sudden
temperature increase in the mixing chamber.
2) When the unit is pressurized, check for leaks at the fittings and unit.
3) Open end-fixture to establish flow. Observe lock-out/tag-out procedures.
4) MIXED TEMPERATURE ADJUSTMENT:
a) Facing top of the valve, turn handle clockwise to decrease the mixed
temperature, or counter-clockwise to increase mixed temperature. Allow
the mixed temperature to stabilize at least one minute before making
another adjustment.
b) In some conditions, the outlet temperature setting is adjusted above
120°F. This can be done by turning the handle counter-clockwise until
desired mixed temperature is reached. Allow unit to stabilize at least one
minute before making adjustment.
5) SETTING MIXING VALVE TO RECIRCULATING SYSTEM:
a) After installation is complete (refer installation instructions), close and tag
all fixtures not used in this procedure.
UNION NUT
b) Turn off recirculating pump.
c) Open fixture/s to flow greater than the minimum flowrate of the mixing
valve. Tag open fixture/s to prevent any possible usage of untampered
water.
MIX TEMP
FIXTURES
d) Allow water to flow through the mixing valve until water temperature is stable. If necessary, re-adjust the valve according to "ADJUSTMENT" instruc tions.
e) Once the temperature is set, start recirculating pump and allow the system to reach set temperature.
f ) Measure water temperature downstream of the recirculating pump and adjust the aquastat to shut-off the pump when the return water exceed the set
point by 2°F. Set the aquastat to restart the pump when the return water drops 5°F below set temperature.
g) Set the balancing valve in the full open position.
h) Close all fixture/s and make sure no demand is allowed. The cold inlet temperature to the mixing valve should be warm.
i ) Allow the system to run without demand for at least 30 minutes. In some cases, an increase in water temperature may occur during a no load period.
If this occurs, slowly close balancing valve until water temperature is back to the original set temperature.
MAINTENANCE
Periodic inspection and maintenance by a licensed plumber is required to insure proper and efficient performance of the unit. Frequent cleaning and
replacement of shuttle O-ring is required and recommended. Shuttle O-ring requires periodic lubrication using silicone based lubricant only. PTFE or
petroleum based lubricant may cause O-ring swelling.
REPAIR KIT INFORMATION
MODEL NO. QTY PART NO. DESCRIPTION MATERIAL
(34A200RK)
1 A215300 SPRING 304 STAINLESS STEEL
1 W434805 SHUTTLE SUB-ASSY
MVA-RK
F326400 SHUTTLE 20% GLASS FILLED NORYL
I637800 THERMAL ACTUATOR ALL WETTED PARTS-Cu
D492300 O-RING, -024 EPDM
1 I882900 INSTRUCTION SHEET CARD STOCK
TROUBLE SHOOTING
PROBLEM CAUSE SOLUTION
Mixed temperature fluctuating or erratic
Mixed temperature will not adjust to desi red
temperatur e
No flow
Hot water backing- up in cold water sup ply
Cold water ba cking-up in hot water su pply
THIS PRODUCT MEETS THE REQUIREMENTS OF THE EPA SAFE DRINKING WATER ACT
CALIFORNIA PROP 65: WARNING:
This product complies with U.S. Safe Drinking W ater Act (SDWA). Suitable for potable water applications intended for human consum ption.
WARNING: FAILURE TO FOLLOW ABOVE INSTRUCTIONS COULD RESULT IN UNSAFE DISCHARGE TEMPERATURE, WHICH MAY
CAUSE INJURY OR DEATH.
Cold and Hot water inlet press ure differential Install pre ssure redu cing valve or pressure
greater than 30 psi d limiting de vice to maintain equal
Shuttle ass embly dam aged or worn Replace with repair kit.
Setpoint adju stment at maximu m setting Increase inlet water temperature setting
Hot water inlet tem perature within 15°F of outlet m ix
setpoin t.
Hot water tempe rature above 180°F Adjust water he ater temperature
Inlet check valves clogge d or damaged Replace inlet check valves
Supply valves closed Check cold an d hot water supply valves
Inlet check valves clogge d or damaged Clean or repl ace
Strainers completely clogged Clean or repl ace
Loss of supply press ure Check with lic ensed plum ber
Cold water in let check valve defective, clogged or Inspect, clean or replace cold water check
damag ed and cold water pre ssure is less than valve
hot water sup ply pressure
Hot water inlet check valve defective, clogged or Inspect, clean or replace hot water check
damag ed and hot water pres sure is les s than valve
cold water s upply pressure
and consi stent pressu res.
allowi ng valve to mix.
Increase hot water inlet to more than 15° F
above outlet setting .
Cancer and Reproductive Harm - www.P65W arnings.ca.gov
I639200- REV. J
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