Riverside Hydronics 400 - Sensor Locations and Thermal Well; Building Return Temperature

M3 CONDENSING WATER BOILER
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4.2 Sensor Locations and Thermal Well
The boiler uses an operating sensor and a monitoring sensor. One sensor is located in the thermal well in the upper
portion of the boiler water tank. A second sensor for use external to the boiler is coiled and located in the control
enclosure along with the Sensor Thermal Well. The Sensor Thermal Well can be installed in the piping going to or
from the boiler, based on application. As shipped, the sensor located in the upper portion of the boiler is used as the
operator and is connected to P1 (see wiring diagram) and the 25 foot long sensor coiled in the control enclosure is
used as the monitor and is connected to P2 (see wiring diagram). The operating sensor location is based on the
boiler application. The operating and monitoring sensor wiring to the TempTrac control can be swapped to make the
25 foot long monitoring sensor serve as a remote operating sensor.
Multiple boiler installations or adding outdoor reset requires a communication-based (non-analog) BMS such as an
Ontrac
®
control.
IMPORTANT: See boiler application guidelines regarding placement of multi sensor well, as well as sensor
configuration and Ontrac operation.
4.3 Filling the Boiler
1. Fill the system with water. To be sure that the unit is not “air bound,” open the relief valve. Leave the valve open
until a steady flow of water is observed. Close the valve and complete filling the system.
2. In hard water areas, fill water should receive water treatment to reduce the introduction of minerals into the
system. Excessive buildup of minerals in the heat exchanger can cause a non-warrantable failure.
3. Make sure there are no system leaks. DO NOT use petroleum based stop-leak products. All system leaks must
be repaired. The constant addition of make-up water to a closed loop boiler system can cause minerals to
collect in the heat exchanger. Excessive buildup of minerals in the heat exchanger can cause a non-
warrantable failure.
4. For systems requiring freeze protection, use only hydronic system antifreeze with a maximum concentration of
50%. Follow the glycol manufacturer’s instructions. DO NOT use undiluted or automotive type antifreeze.
4.4 Building Return Temperature
Condensing boilers like the M3 utilize colder building return water to increase boiler efficiency and lower flue gas
temperatures to allow the use of plastic vent pipe like PVC. Higher building return water temperatures can result in
higher vent temperatures that exceed the temperature limits for plastic venting systems.
See Section 8 “Venting” for the maximum building return water temperatures allowed for the selected venting system
material to be installed.