Speed Queen Washer Not Getting Hot Water: Troubleshooting... | appliancefaults.com

Technical Background:

The Machine Control Unit (MCU) controls the water inlet valves based on the selected wash cycle and temperature setting. The MCU receives feedback from the temperature sensor (thermistor) to monitor water temperature. For models with heating elements, the MCU activates the element when necessary to maintain the desired temperature. Voltage (120V AC) is supplied to the hot water valve and heating element (if equipped) through relays on the MCU board.

Symptoms:

The Speed Queen washer is filling with water, and completing the wash cycle, but the water is not hot, or not as hot as it should be. Clothes may not be getting properly cleaned, and detergent may not be dissolving correctly.

Possible Causes:

Faulty water inlet valve (hot side).
Defective temperature sensor (thermistor).
Heating element malfunction (if equipped; some models use only hot water inlet).
Problem with the Machine Control Unit (MCU) or its programming.
Wiring issue or loose connection in the heating circuit.
Clogged or restricted hot water inlet hose.

Solution:

1

Disconnect power to the washer at the breaker panel (LOTO).
2

Locate and inspect the hot water inlet valve. Use a multimeter to check for 120V AC when the hot water fill cycle is active. If no voltage is present, proceed to check the MCU.
3

If voltage is present at the hot water valve, but water isn't flowing, the valve is likely defective and needs replacement.
4

Locate the temperature sensor (thermistor). Disconnect it and measure its resistance using a multimeter. Compare the reading to the manufacturer's specifications (usually a chart correlating temperature to resistance).
5

If the resistance is significantly off, replace the thermistor.
6

If the washer has a heating element, inspect it for continuity using a multimeter. A reading of infinity indicates a failed element. Replace the element.
7

Check all wiring connections related to the hot water valve, thermistor, and heating element (if present) for looseness or corrosion. Repair or replace as necessary.

Safety Warning:

Disconnect power to the washer at the breaker panel before performing any repairs. Verify the power is off using a multimeter. Some components may retain a charge even after the power is disconnected. Exercise caution when working with electrical components.

Prevention:

Periodically check and clean the water inlet screens to prevent clogging. Use high-efficiency (HE) detergent to minimize residue buildup. Run a cleaning cycle with a washer cleaner every 1-3 months.

Expert Tip:

On some Speed Queen models, you can enter a diagnostic mode by pressing and holding the Start/Pause button while simultaneously pressing the Cycle Selector knob three times within 5 seconds. This allows you to run individual component tests to verify their operation.

Frequently Asked Questions

•How do I find the technical specifications (resistance values) for my temperature sensor?

You can usually find the specifications in the service manual for your specific Speed Queen model. The service manual is available through the Speed Queen website, appliance parts retailers, or technical documentation services. Search online using your model number followed by "service manual."

•If the MCU isn't sending voltage to the hot water valve, what should I check on the MCU board?

Carefully inspect the MCU board for any signs of burned or damaged components, especially around the relay that controls the hot water valve. If you're comfortable with electronics repair, you can test the relay itself. However, MCU repair can be complex and may require specialized tools and knowledge. Consider replacing the entire MCU board if you suspect it's faulty.

•My Speed Queen doesn't have a heating element. Could the problem still be the temperature sensor?

Yes, even if your washer doesn't have a heating element, the temperature sensor still plays a crucial role. The MCU uses the sensor's readings to regulate the amount of hot and cold water mixed to achieve the desired wash temperature. A faulty sensor can cause the washer to fill with too much cold water, even if the hot water inlet valve is functioning correctly.

Speed Queen Washer Not Getting Hot Water: Troubleshooting Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•How do I find the technical specifications (resistance values) for my temperature sensor?

•If the MCU isn't sending voltage to the hot water valve, what should I check on the MCU board?

•My Speed Queen doesn't have a heating element. Could the problem still be the temperature sensor?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: