Operating instructions

MAXI-THERM PIPING WITH A “MIXING VALVE”
Usually, the maximum temperature of the outlet water will stay near the setting of the Maxi-Therm thermostat.
In some cases, however, hot water usage patterns can cause the outlet water temperature to rise significantly
above the control setting.
The temperature of water going to the fixtures may be more carefully controlled through the use of a mixing
valve. This device blends a controlled amount of cold water with the hot water from the Maxi-Therm to provide a
more constant temperature at the fixtures. Typical mixing valve piping is illustrated in Figure 13.
DOMESTIC WATER PIPING FOR DISTANT FIXTURES
In some cases the furthest fixture may be quite distant from the Maxi-Therm. In such an installation the
configuration shown in Figure 12 or 13 would result in an unacceptable delay before hot water reaches these
distant fixtures. Even if all the fixtures are relatively close to the Maxi-Therm, the building owner may want hot
water at all fixtures as soon as they are opened.
Figure 14 illustrates a solution to this problem. In it, a pipe is run from the furthest fixture on each branch back to
the return of the Maxi-Therm. A small bronze circulator is mounted in this line and is wired so as to run continu-
ously. A check valve in this line permits flow towards the Maxi-Therm inlet only.
When no fixtures are drawing water, the bronze circulator moves hot water from the Maxi-Therm to end of the
branch just below the last fixture, then back to the inlet of the Maxi-Therm via the return pipe. When a fixture is
opened, hot water is already out in the branch very close to the fixture and hot water appears at it almost immedi-
ately. The check valve prevents cold water in the Maxi-Therm’s inlet pipe from passing around the tank and
heading directly to the fixture.
Because hot water is always circulated in the hot water branch, the entire branch should be insulated to prevent
excessive heat loss.
MANIFOLD DOMESTIC WATER PIPING
Figure 15 illustrates the recommended method of piping the domestic water side of several tanks together. All
Maxi-Therms are piped in a “reverse-return” manner just like the boiler piping. This balances the pressure drop
through each tank, resulting in an even flow rate through each tank.
Each tank must have its own T&P valve. It is recommended that each tank be equipped with its own isolation
valves, unions, and drains so that one tank may be removed from the system.
VII. WIRING
WARNING
A mixing valve does not eliminate the risk of scalding:
• Set the Maxi-Therm thermostat as low as practical.
• Feel water before bathing or showering.
• If anti-scald or anti-chill protection is required, use devices specifically designed
for such service. Install these devices in accordance with their manufacturer’s
instructions.
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