Rheem Versa Spa Heaters Operating Instructions - Page 30

ELECTRICAL - IID, SOLID STATE THERMOSTAT If the pool/spa/hot tub water is too cold, troubleshoot the system as follows: Check voltage at 24 V terminals. VOLTAGE BETWEEN 21.5-28.5 V. Set control to max. temperature. After 2-3 cycles, check water temperature. VOLTAGE OUTSIDE RANGE 21.5-28.5 V. Check transformer, 120 V supply, correct as necessary TEMPERATURE BELOW 105°F Disconnect sensor leads from circuit board. Measure sensor resistance with ohmmeter. TEMPERATURE 105-106° F. Control ok. RESISTANCE 1-14k OHMS. Check water temperature; estimate expected sensor resistance from chart below. RESISTANCE 0 OHMS (SHORT CIRCUIT) Check system for shorted wires or open circuits. Replace sensor if necessary. MEASURED AND ESTIMATED RESISTANCE MATCH WITHIN 20 PERCENT. Disconnect potentiometer leads from circuit board. Measure resistance with ohmmeter. If resistance is: 0-100 ohms at minimum setting and 9k to 11k at maximum setting, replace circuit board. Above 11k ohms but less than 15 k ohms, replace potentiometer. Above 15k ohms, fix loose or broken wires; replace potentiometer if necessary. Reconnect all leads and check out system. MEASURED AND ESTIMATED RESISTANCE DON'T MATCH. Replace sensor. Reconnect all leads and check out system. If the pool/spa/hot tub water is too hot, troubleshoot the system as follows: Check voltage at 24 V terminals. VOLTAGE BETWEEN 21.5-28.5 V. Set control to max. temperature. After 2-3 cycles, check water temperature. VOLTAGE OUTSIDE RANGE 21.5-28.5 V. Check transformer, 120 V supply, correct as necessary. TEMPERATURE ABOVE 108°F Disconnect sensor leads from circuit board. Measure sensor resistance with ohmmeter. TEMPERATURE 105-106° F. Control ok. RESISTANCE 1-14k OHMS. Check water temperature; estimate expected sensor resistance from chart below. RESISTANCE ABOVE 15k OHMS (OPEN CIRCUIT) OR SHORT CIRCUIT. Fix loose or broken wires. Replace sensor if necessary. MEASURED AND ESTIMATED RESISTANCE MATCH WITHIN 20 PERCENT. Disconnect potentiometer leads from circuit board. Measure resistance with ohmmeter. If resistance is: 0-100 ohms at minimum setting: 9k to 11k at maximum setting, replace circuit board. Above 11k ohms, replace potentiometer. 0 ohms (short circuit), replace potentiometer. Reconnect all leads and check out system. MEASURED AND ESTIMATED RESISTANCE DON'T MATCH. Replace sensor. Reconnect all leads and check out system. SENSOR RESISTANCE AT VARIOUS TEMPERATURES Temperature (deg. F) 61 68 70 77 86 88 95 104 106 Resistance (k ohms) 14.92 12.49 11.88 10.00 8.06 7.69 6.53 5.33 5.10 30