FAQ
TL;DR: One confirmed fix replaced pressure switch 6630-839.3; "pressure switch has definitely been replaced." If your K7 Premium Full Control Plus gun won’t change modes or pair, a service swap of that switch restored operation in the reported case. [Elektroda, mikigryf, post #18008868]
Why it matters: This helps K7 Premium Full Control Plus owners diagnose MIX‑mode lock and get a proven, service-backed resolution fast.
Quick Facts
- Confirmed service fix: pressure switch No. 6630-839.3 replacement resolved pairing and operation after a fault. [Elektroda, mikigryf, post #18008868]
- Symptom profile: display stuck in MIX, +/- works in reverse, triggered right after a tap was turned off mid-use. [Elektroda, Porebiak, post #17991771]
- Quick workaround reported: power off overnight, then re-pair with the gun held very close; normal modes returned. [Elektroda, cinek20213, post #17979804]
- Trigger condition: no water supply or a broken hose can lock the lance program. [Elektroda, cinek20213, post #17992608]
- Fault mode behavior: only 3-step pressure control available within MIX when locked. [Elektroda, cinek20213, post #17969900]
What are the telltale symptoms of the K7 gun fault?
The gun locks in one mode and the display ignores lance rotation. Pressure adjustment works in reverse, so pressing “–” increases pressure. Maximum pressure shows when the display indicates minimum. These signs point to a control mismatch between the gun and washer. [Elektroda, mikigryf, post #17915220]
What triggers the MIX-mode lock or reversed +/-?
A sudden water cut during operation can trigger it. One owner’s child closed the tap mid-use. The washer then pulsed and the gun stayed in MIX with plus/minus reversed. Avoid cutting water flow while the trigger is pressed. [Elektroda, Porebiak, post #17991771]
Can this issue clear by itself after a reset?
Yes. One case cleared after powering off, waiting overnight, then re-pairing with the gun held close. The lance modes returned the next day. This simple reset saved a service visit in that instance. [Elektroda, cinek20213, post #17979804]
How do I re-pair the K7 Full Control Plus gun?
Try this: 1. Power the washer off at the mains. Ensure a stable water supply. 2. Power on later, then initiate pairing while holding the gun/lance very close to the unit. 3. Confirm the display responds to lance rotation and test all modes. [Elektroda, cinek20213, post #17979804]
What did the service center change to fix it?
A documented fix replaced the pressure switch (No. 6630-839.3). After replacement, the unit paired and worked normally. "Pressure switch has definitely been replaced." This ties the fault to that component in the confirmed case. [Elektroda, mikigryf, post #18008868]
My gun won’t pair at all—what should I do?
If pairing fails repeatedly, seek service. One report states the washer was "unable to pair with the gun" until the pressure switch was replaced. After that, pairing and operation were restored. [Elektroda, mikigryf, post #18008868]
Will replacing the spray gun itself solve the problem?
Not reliably. One owner received a new gun earlier, yet the same issue reappeared after a tap was turned off during use. That suggests the root cause can lie in the washer’s internals, not only the gun. [Elektroda, Porebiak, post #17991771]
Why does the +/- control work in reverse when it’s stuck?
In the fault state, control logic desynchronizes. Users observed “plus is minus and minus is plus,” along with MIX-mode lock. This indicates the gun’s commands are misinterpreted until reset or repaired. [Elektroda, Porebiak, post #17991771]
Is there a quick workaround before service?
Yes. One owner powered the washer off, waited until the next day, then re-paired at very close range. The gun resumed normal operation. That single case resolved in about one day of downtime. [Elektroda, cinek20213, post #17979804]
How can I prevent the fault from occurring?
Keep a steady water supply while washing. Do not shut the tap while the trigger is pressed. Avoid dry running or hose breaks during operation. These conditions preceded a lock in a reported case. [Elektroda, Porebiak, post #17991771]
Why do I only get 3-step pressure in MIX when it fails?
When locked in MIX, the gun allows only three pressure steps. Other programs don’t engage despite lance rotation. This constrained control is part of the fault signature users reported. [Elektroda, cinek20213, post #17969900]
What should I check before sending it to service?
Verify stable water flow and inspect hoses for damage. Restore water, then power-cycle and test from scratch. One user reported the problem disappeared the next day after restarting and using the lances again. [Elektroda, cinek20213, post #17992608]
What exact part number fixed it under warranty?
Pressure switch No. 6630-839.3. The service report cites its replacement, after which pairing worked and the unit operated properly. Note that the gun and lance showed prior use, indicating they were not swapped. [Elektroda, mikigryf, post #18008868]
How will I know the repair worked?
The display will respond to lance rotation, pressure controls behave normally, and pairing is stable. As one owner confirmed, "the defect has been rectified and the unit is working properly." [Elektroda, mikigryf, post #18008868]
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