DXR Drainback
Page 17
WATER HEATER PLUMBING
NOTE:
Prior to connecting the solar system to an existing water heater, be sure to turn-off the power to the water
heater at the circuit breaker and drain the water tank to a suitable drain location. The installer should also check
the quantity and condition of the anode rod(s) and recommend replacement if necessary.
To minimize expense and heat loss, the tank should be near the collectors and central to points of greatest water
demand. It should be located indoors, in as warm of a spot as possible. It should be located with adequate
ventilation, with a minimum of 6-8 inches of clearance and with ready access to controls and serviceable parts.
The solar system feed and return lines will be plumbed into the water heater at the cold water feed and at the T&P
connection ports. The existing T&P relief valve will be removed and replaced with a long probe T&P at the hot
water feed to the fixtures as shown in the illustrations below (additional illustrations on pages 30-32).
Side
connect
plumbing
Top
connect
plumbing
Provision should be made to prevent water damage in case of leakage. A catch pan with a minimum of 3/4” drain
line at least 2” in height may be installed and pitched for proper drainage where the tank is installed in or above the
living space. Electrical service of 240V should be available for the element and 110V for the pump and controller.
System subassemblies which are exposed to public traffic and are maintained at elevated temperatures shall either be
insulated sufficiently to keep exposed surface temperatures below 60°C (140°F) during operation, or they shall be
suitably isolated. Any other exposed areas that are maintained at hazardous temperatures shall be identified with
appropriate warnings.
SENSOR MOUNTING AT WATER HEATER
The sensor mounted at the water heater should be located in the lower portion of the tank. The sensor should be of
the strap/bolt-on type. The strap/bolt-on sensor should by wedged securely between the tank wall and the thermostat
bracket or surrounding insulation.
Procedure:
1.
Insure the electrical power to the water heater has been turned off at the circuit breaker panel.
2.
Remove the upper element access panel, set the thermostat to 120°F and disconnect the wires from the
thermostat to the lower element (if present). Tape and coil aside.
3.
Remove the lower element access plate (cover) and insulation to expose the tank wall.
4.
Wedge the sensor securely under the bottom thermostat bracket, insuring the sensor makes good contact
with the tank wall.
5.
If a bottom thermostat bracket is not available, using a large flat-head screwdriver, scrape back the
insulation from the tank wall enough to wedge the sensor securely against the tank.
6.
Attach 18/2 sensor wire to the wires of the sensor and run the wire up the outside of the tank to the
controller attaching it to the terminals marked tank and common.
7.
Replace the insulation and cover.
