8
THREE WAY MIXING VALVES
IMPORTANT:
When installing a three-way mixing
valve, it is necessary that return circulation be piped to
feed the cold water side of the mixing valve and heater.
See Figure No. 13.
As the temperature of the mixed liquid increases, the
piston moves toward the hot seat port B. See Figure 3
on page 2. This movement decreases the hot flow and
increases the cold flow through port C. See Figure 3 on
page 2. The thermostat maintains the piston in the
proper position for the desired mixed temperature.
TO CHECK THE OPERATION OF A THREE-WAY VALVE
USED AS A MIXING VALVE PROCEED AS FOLLOWS:
Check the packing gland to see if it is only hand tight. If
this gland is too tight, it will bind the valve stem. Then
open one or two outlets in the hot water line to establish
a flow of water through the valve. Check temperature on
thermometer. If it is not at the desired point, increase or
decrease the temperature by turning the adjustment
wheel in the proper direction for a higher or lower
temperature. The proper direction is indicated by an
arrow on valve bracket. Two turns of the adjustment
wheel should make an appreciable change in outlet
temperature.
If the temperature at the outlet drops below the desired
point, check the temperature of the hot water entering
the valve. If it is below the required temperature, the coil
or heater is not making enough hot water. This condition
must be remedied before any further adjustment can be
made on the three-way valve.
WHEN IN NEED OF INFORMATION
When contacting the factory or one of its representatives
in regard to a regulator, be sure to give all the name
plate Information, fastened to the bellows housing. This
name plate is shown in Figure No. 14.
CIRCULATING PUMP
CHECK
VALVE
REGULATOR
WITH 3 WAY
VALVE
COIL IN
BOILER
PORT
"A"
PORT
"C"
PORT
"B"
COLD BYPASS
HOT BYPASS
BOILER
RETURN CIRCULATION
COLD WATER
SUPPLY
TO BUILDING
Figure No. 13
Figure No. 14
Summary of Contents for Bell & Gossett Hoffman Specialty 1140 Series
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