Weil-McLain WM97+ Product Manual page 33

CWH
companion water heater
Troubleshooting
Excessive domestic water temperature
1 Adjust WM97+ control settings and check operation.
• Follow instructions in the boiler manual and this manual to adjust tank temperature
and boiler water temperature.
• If controls are set properly, check tank sensor installation and operation.
• See the illustration at right for locations of the sensor wells. The lower well is on the
side opposite the DHW connections. (This illustration shows a right-oriented tank.)
• Check whether sensors are inserted completely into their wells. If not, press in firmly
and recheck CWH operation.
• If sensors are properly inserted in their wells, disconnect each sensor harness and
attach an ohmmeter. The table below shows the correct values for the sensor at
various temperatures.
Temp Sensor ohms
(°F)
Min
32 34265
40 27834
50 21630
60 16944
70
13372
80 10629
• Use the resistance values at 32°F, 60°F, 70°F and 212°F to
measure the sensor resistance at known temperatures
(ice point, room temperature and sea level boiling
point). For ice point and boiling point, insert the sen-
sor in water at that temperature. Use an ohmmeter to
read resistance value. To check whether the WM97+
2 Recirculation loop needed?
• Installing a properly-sized recirculation loop will not
only provide prompt delivery of hot water, but it will
3 Thermostatic mixing valve set too high?
• Follow instructions in the mixing valve manual to
check mixing valve setting temperate. Adjust if neces-
4 No thermostatic mixing valve installed or mixing valve is defective?
IF THE MIxING VALVE IS NOT INSTALLED,
DISCONTINUE USE OF THE CWH AND INSTALL
THE MIxING VALVE FOLLOWING INSTRUCTIONS
IN THIS MANUAL AND THE MIxING VALVE
MANUAL.
Part number 635-500-156/0113
— Product Manual
(continued)
Temp Sensor ohms
(°F)
Max Min
37871 90 8504
30764 100 6847
23907 110 5545
18727 120 4517
130
14780 3698
11747 140 3043
Temp Sensor ohms
(°F)
Max Min Max
9399 150 2517 2782
7568 160 2091 2311
6129 170 1744 1928
4992 180 1461 1615
190
4088 1229 1359
3364 200 1038 1147
control is correctly sensing temperature, you can use
a resistance decade box. Connect the decade box tem-
porarily in place of a sensor and read the correspond-
ing temperature on the WM97+ control display. The
temperature should be close to the value corresponding
to the input resistance.
provide circulation and mixing of the water within
the tank.
sary following the manual's specified procedure.
• The CWH
valve installed per the instructions in this manual and
the mixing valve manual.
• Follow instructions in the mixing valve manual to
check valve operation. If valve is correctly installed and
does not operate correctly, replace the mixing valve.
must not
be operated without a mixing
33