Hotpoint WML730 pump / PCB problem
Hi I was hoping for some guidance on sorting out my hotpoint WML730 washing machine.
The pump had started leaking on this to the point that we only realised when it packed up. Pump was replaced with a new one but it didn't work. Testing the pump in isolation showed it was working fine when 240v was applied to it.
I put a meter across the wiring from the PCB to the pump and this showed that only a voltage of around 130-135v was coming to the pump.
Checking the PCB circuit board showed that one of the transistors in it had "blown up" - it is the one marked as Q011 on the board and marked as Z0107NA. The contents of the rest of the PCB looks intact. No dry joints, bulging capacitors etc..
The burned out transistor has been replaced but it has not solved the problem. The output to the pump is still around 135v.
Any help would be greatly appreciated in pinpointing where the problem might be.
Many thanks
Gary
Solution Summary
AI-generated from this discussion
This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.
Hotpoint WML730 not powering drain pump after leak; control module suspected
- The problem
- The drain pump on a Hotpoint WML730 had been leaking and the machine then stopped working. The pump was replaced, but the new pump did not run in the machine. When tested separately, the pump operated on a direct 240V supply. A meter reading taken at the pump wiring from the PCB showed about 130–135V. On the PCB, component Q011 marked Z0107NA had visibly failed and was replaced, but the pump supply remained around 135V.
- Likely cause
- The strongest diagnosis in the discussion is damage to the control module caused by the leaking pump. The accepted reply notes Q011/Z0107NA is a triac and that associated parts in the same circuit, such as nearby resistors, tracks or driver components, may also have failed. It also notes the 130–135V reading may be misleading on a triac-switched output when measured with a digital meter.
- What fixed it
- Recommended action was to inspect the pump wiring loom and connectors for corrosion, overheating, tracking or high-resistance connections caused by the leak, and to check the PCB around Q011 for damaged tracks or nearby failed components rather than assuming the triac alone was faulty. If the pump is confirmed correct, works on direct 240V, and wiring is sound, the accepted advice was that module repair or replacement is the likely practical remedy. The exact repair was not confirmed in the thread.
- Checks to try
- Pump tested in isolation on 240V and found working
- Voltage at pump wiring from PCB measured at around 130–135V
- PCB inspected and Q011 marked Z0107NA found blown
- Q011/Z0107NA replaced but symptom remained
- Advised to inspect pump wiring loom and plugs for damage, corrosion or overheated pins
- Advised to check PCB area around Q011 for failed resistors, damaged tracks or nearby driver components
- Advised to confirm the replacement pump matches the original specification
- Parts or tools mentioned
- Drain pump
- PCB control module
- Q011 triac marked Z0107NA
- Meter
Safety: Further diagnosis should be carried out by a suitably qualified appliance engineer.
1 Answer
Hi Gary,
What you describe is very commonly a control-board damage issue caused by the leaking pump, but the 130–135V reading needs treating with caution because a digital meter can show misleading voltages on a triac-switched AC output.
Before checking anything internal, isolate the washing machine from the mains. If you are not confident with live electrical testing or PCB repair, it’s best to use a qualified appliance engineer.
1. Check how the voltage was measured A drain pump on these is usually switched by a triac, not a relay. A high-impedance meter can show a “ghost” or partial voltage even when the circuit cannot supply proper current. The key test is whether the pump gets a solid 230–240V under load during drain, or whether the board is failing to switch it fully.
2. Inspect the pump wiring loom and plugs carefully Follow both pump wires back to the module. Look for damaged insulation, green corrosion, overheated connector pins, or tracking caused by the original leak. A bad neutral or high-resistance connection can give odd readings.
3. Check the PCB around Q011 The Z0107NA is a triac. If it blew, the gate resistor, track, or nearby driver transistor/component may also have failed. Very often the triac is not the only casualty. Check for burnt/open resistors and damaged copper tracks around that section.
4. Confirm the pump itself is the correct type Make sure the replacement pump matches the original spec and connector arrangement. An incorrect pump can confuse diagnosis.
5. Consider the module as the likely fault If the pump works on a direct 230V supply, wiring is sound, and the machine still won’t deliver proper power to the pump during drain, the control module is the main suspect. On these Hotpoints, module repair or replacement is often the practical fix.
If you want to narrow it down further, post clear photos of both sides of the PCB around Q011 and the pump connector area.
WhitegoodsHelp AI
WhitegoodsHelp AI Assistant
This answer was generated automatically by the WhitegoodsHelp AI Assistant. It is not provided by an engineer or any other qualified person, may be inaccurate or incomplete, and is not professional or technical advice. Do not rely on it. Always use your own judgement and consult a qualified engineer before carrying out any electrical, gas or water work. Use is entirely at your own risk. See our full Terms of Use.
SAFETY FIRST: READ BEFORE ACTING ON THIS GUIDANCE
Never work on a live appliance
Always unplug it at the mains before going near it with any tools.
Never attempt gas work
By law, gas appliances must only be worked on by a Gas Safe registered engineer. If your fault involves gas, stop and call a professional. Do not attempt it yourself.
Watch for sharp edges
Outer panels are smooth, but internal parts have sharp machined edges. Wear protective gloves and arm sleeves.
Water appliances can leak
Turn off the water supply before disconnecting any hoses.
Know your limits
If you are not confident testing or working inside the appliance, stop and call a professional.
AI guidance, not guaranteed
This response is generated automatically by the WhitegoodsHelp AI Assistant. It is not professional or technical advice, may be incomplete or wrong, and must not be relied upon. Always use your own judgement and consult a qualified engineer before any electrical, gas or water work.
This is general information only and is not professional advice. The WhitegoodsHelp AI Assistant is not an engineer and is not qualified. See our full Terms of Use.
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