A tankless water heater is a very small but very powerful and extremely efficient electric water heating system. The tankless water heater, whose technology has earned 5 U.S. Patents and many more foreign patents, is much more than just a water heater.
| COMPONENT | TYPE OF TEST | POWER STATUS (ON/OFF) | EXPECTED RESULTS |
| Incoming Power Lugs (Control Board) | Verify Power to Lugs — Voltage | ON | Phase Check Measurements (Individual Circuit) L1 to L2 208 — 240 Volts (AC) L1 to Ground 110 — 120 Volts (AC) L2 to Ground 110 — 120 Volts (AC) Sequence Check Measurements (Circuit to Circuit) L1 to L1 0 Volts (AC) L2 to L2 0 Volts (AC)
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| Temperature Sensors (Chamber) | Continuity — Ohms | OFF | Ohm readings should be taken after the heater has been cooled down so that the temperature in the chamber is uniform. All temperature sensors should read within 25 ohms of each other. For EXAMPLE, on an RA-28 with a 50 deg. F inlet water temp., the expected temperature sensor readings may read as follows: THIN ~ 358 Ohms TH1 ~ 348 Ohms TH2 ~ 353 Ohms TH3 ~ 346 Ohms TH4 ~ 351 Ohms Most temperature sensor readings will fall within 200 to 400 ohms, provided the heater is cooled down first.
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High Temperature Limit Switch |
Continuity — Ohms | OFF | Should read —0- ohms
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| Heating Element (Chamber)
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Continuity — Ohms | OFF | Read across screws at the Red & Black wires. Ohm readings should fall into the following range (also allow +/- 1% tolerance): 4500W ~ 12.5 to 13.5 Ohms 5500W ~ 9.5 to 10.5 Ohms 7000W ~ 7.5 to 8.5 Ohms
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| COMPONENT | TYPE OF TEST | POWER STATUS (ON/OFF) | EXPECTED RESULTS |
| Heating Element (Control Board) |
Full Flow Test — Amps | ON | With the power on to all circuits, and water running at full flow at a sink or tub faucet, measure the amps on each Red or Black element wire, going from the control board to the element. Maximum expected readings as follows: RA-28 ~ 29 amps ea. RA-22 ~ 23 amps ea. RA-18 ~ 19 amps ea. RA-14 ~ 29 amps ea. RA-11 ~ 23 amps ea. RA-9 ~ 19 amps ea. Allow for +/-10% tolerance in readings due to meter error. |
| Heating Element (Control Board) |
Modulation Test — Amps | ON | With power on and water at (half) flow at the sink faucet, check amps at each element. Power should modulate and amp readings may fluctuate, but all should read approximately the same amps.
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| Level Detector Switch (Chamber)
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Ohms | OFF | Each contact should read -0- ohms to ground. |
| Moisture Detector Switch (Control Board) |
Ohms | OFF | Should normally read open. If reading continuity, check for water leaks or water on the switch pad (mounted on the bottom of the base pan). Correct the leak or dry the switch and retest.
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