SaluSpa GCF (6CF) & E18 Errors: What They Mean, What to Do

By Jake Weber · Published October 23, 2026

GCF (often read as “6CF”) and E18 are grounding alarms. Of the manuals I checked, only Bestway’s manual for its S400105/S400205 pumps lists them: it defines GCF as “Ground connection failed” and E18 as “Detected electric from ground wire.” Get everyone out of the water and bypass nothing. For GCF, you can try one other outlet you know is grounded, with no extension cord, once. E18, or a GCF that comes back: electrician. A pump fault: Bestway.

Which pumps this covers. Both codes are in the error-code table of Bestway’s 2023 manual for its S400105/S400205 pumps (p. 17), cited below as the S400 manual. I also checked the three older manuals this site uses, the AirJet Plus (pump S100205, 2020), the AirJet (pump S100105, 2020) and the Coleman SaluSpa 90363 (2017), and neither code appears in any of them. That doesn’t mean every SaluSpa-branded pump works the same way, and the S400 manual doesn’t say which spas use these pumps, so the label on your pump and its own manual decide.

Safety note: check your pump against the 2024 recall. In September 2024 the U.S. Consumer Product Safety Commission announced a recall of about 866,000 Bestway AirJet and HydroJet spa pumps sold with SaluSpa, Coleman and Hydro-Force spas from May 2021 to May 2024, because they can overheat and catch fire (recall 24-359). Before troubleshooting anything below, read the model number on the label on the side or back of your pump. The recalled models are P05332, P05339, P05711, P05807, P07000, P07001, P05511, P07034 and P07572. If yours is one of them, stop using it and follow the CPSC recall notice or Bestway’s recall page for a free replacement or a refund. The SaluSpa pump recall guide walks through the label check and what to do next.

Electrical safety comes before any step on this page.

• Everyone out of the water while the code is showing, and nobody reaches in “to check.” That’s my rule: both alarms are about the path electricity takes to ground.
• Power off the dry way. Unplug only with dry hands, a dry plug and dry footing, standing outside the water. If you can’t, or the plug, cord or outlet looks wet or damaged, don’t touch it: switch off the breaker for that outlet instead. That’s my safety call. The S400 manual’s own rule: no spa use during storms, and “plug in with wet plug is definitely forbidden” (p. 4).
• Felt a tingle? The CPSC’s advice: “Move away from the source of the shock. Get out of the water.” Someone else is being shocked? Don’t touch them. “Immediately turn off all power. If the power is not turned off, rescuers can also become victims.” Then call 911. (CPSC, “Don’t Swim with Shocks.”)
• Leave it off until it’s checked. For a GFCI that fails its test, the S400 manual says “Disconnect the power until the fault has been identified and corrected” (p. 3). Applying that to GCF and E18 is my call.
• Never open the pump, bypass or swap the GFCI plug, use a two-prong adapter or an extension cord, or improvise a ground connection.

What does GCF (or “6CF”) mean on a SaluSpa?

“Ground connection failed.” That’s the S400 manual’s wording (p. 17), and it gives two causes: “The ground system of the wall socket where the spa is connected has a problem” and “The pump has a problem.”

Why “6CF”? The display builds letters from seven segments, and in that table the G is drawn exactly like a 6. Many owners type “6CF” when they search, and some online answers explain it as a “communication error” or a “cubic feet” figure. It’s neither: it’s the ground connection alarm.

GCF is not the GFCI. The GFCI is the plug at the end of the cord, with TEST and RESET buttons; when it trips, the pump simply loses power (the SaluSpa reset guide covers its test). GCF is a message on the pump’s display. The S400 manual handles them separately: the GFCI has its own test (pp. 3, 11), and GCF has its own row and fixes (p. 17).

What does E18 mean on a SaluSpa?

“Detected electric from ground wire” (S400 manual, p. 17). The causes listed: “The pump has detected electric from a ground wire. An appliance in your home may have an electric leak,” or “The pump has a problem.” The first fix: “Call an electrician immediately to understand if power is flowing inside the grounding connection.”

That makes E18 the more urgent of the two. Bestway offers no outlet test for it, and neither do I: don’t try other outlets, and leave hunting for the leak to the electrician. Bestway’s blog article on error codes (December 28, 2023) sums up both codes the same way: “E18 and GCF are electrical safety warnings related to grounding issues and should be addressed promptly, often requiring an electrician.”

My rule, as editorial caution rather than a Bestway line: an E18 that disappears on its own doesn’t show the outlet or the wiring has been fixed, so the electrician visit stands.

Why isn’t GCF or E18 in my manual?

Because the code set belongs to the pump, not to the name on the liner:

Bestway’s blog says “All SaluSpa hot tubs feature a GLEDS” (the system behind E18) and “Every SaluSpa hot tub has a GDS – a system that ensures the hot tub is used in an outlet with proper ground connection” (behind GCF). But none of the three older North American manuals lists either alarm, and a blog’s general claim doesn’t override the table for your pump. Some owners report 6CF on a new Coleman 90363E and GCF on a recall replacement pump, which fits: what counts is the pump in the box.

Numbers change meaning too. E08 is the thermal cut-out on the 2020 pumps but “water temperature over 116.6°F” on the S400. Go by the table in your own pump’s manual; the SaluSpa error codes guide covers the other codes.

What can I safely check myself?

Only these, after the safety box:

1. Out of the water, power off, the dry way described in the safety box.
2. Is it plugged straight into a grounded outlet? No extension cord, power strip or two-prong adapter. The S400 manual says the spa “must be connected directly to a grounded socket” (p. 11) and that an extension cord or multi-plug adaptor “is dangerous and can cause the plug to overheat” (p. 12). Some owners traced their 6CF to an extension cord, one with its ground pin broken off. If yours was on one, that ends here.
3. Look, don’t open. Check the plug, cord and outlet for damage without taking anything apart: “do not use the spa if the plug or socket is damaged” (p. 11). A damaged plug or cord goes to Bestway; no tape, no splices.
4. GCF only: one try in one other outlet. Bestway’s first fix for GCF is “Connect the spa pump to a new socket or call an electrician to check the wall socket” (p. 17). If you take the outlet route:
   • The outlet must be verified as grounded, undamaged and within reach of the cord, and its rating must be “suitable for the pump” (p. 11): the S400 runs on 110–120 V AC, 60 Hz, 12 A (p. 13). A three-prong shape doesn’t prove the ground is there. If its ground hasn’t been verified, skip this step and call the electrician.
   • Run the GFCI test before anyone uses the spa (p. 11).
   • One attempt. If GCF comes back, unplug and call an electrician. Don’t go from outlet to outlet.
   • If it clears, the first outlet still has a grounding problem: have an electrician check it before anything goes back on it.
5. E18: skip step 4. No outlet tests. Electrician, immediately.
6. Check the pump’s label against the recall (box above).

When do I need an electrician, and when Bestway?

Bestway’s S400105/S400205 manual mentions a socket with an independent grounding connection if the grounding fault continues. This is an electrical-installation matter for a qualified, licensed electrician—not a DIY fix. Do not bypass the ground connection or keep using the spa while the fault is unresolved.

Until that visit, the spa stays unplugged (the safety box rule). The manual adds: “If you are unsure about the quality of the electrical supply, please consult a qualified electrician before use” (p. 11). Give the electrician the code, Bestway’s wording for it, and the pump’s rating: 110–120 V AC, 60 Hz, single phase, 12 A (p. 13).

Why is my replacement pump showing GCF after the recall?

Some owners report exactly that, including a “GCF SIGNAL” on a replacement pump labeled S100105 P08411. That owner-reported number doesn’t identify the S400 pump this page documents, and Bestway doesn’t publish which pump it ships as the recall replacement, and the S400 manual lists no spa models or part numbers, so I can’t tell you which table your new pump follows. Its own manual can.

Handle it like any GCF: the safety box, then the steps above. If it persists, contact Bestway, since the replacement is part of their recall remedy (888-943-2396, per the CPSC notice). And never go back to the recalled pump: the CPSC says to “immediately stop using” it.

What should I never do when my SaluSpa shows GCF or E18?

FAQ

Is 6CF the same as GCF? Yes. In the S400 manual’s table, the G is drawn with the same segments as a 6 (p. 17), so the display reads “6CF.” The alarm is “Ground connection failed.”

Can I use my hot tub with a GCF error? No. Bestway’s fixes are another outlet or an electrician (p. 17), not “carry on.” Keep everyone out and the power off until the cause is found.

Will pressing RESET on the GFCI clear it? Don’t count on it, and don’t treat a passing GFCI as the all-clear. My conclusion, not a Bestway line: passing the GFCI test doesn’t mean a GCF or E18 alarm is solved, because the manual gives them separate checks and fixes. What RESET does is in the reset guide.

Can an extension cord cause GCF? Some owners traced theirs to one (step 2 above). Either way, the S400 manual rules them out (p. 12).

My older pump never shows GCF. Is it unprotected? Its documented protection is the GFCI plug, which the AirJet Plus, AirJet and Coleman manuals say to test before every use, and not to use the pump if the test fails (pp. 13, 16 and 6). Those manuals describe no separate ground alarm.

It’s freezing and the spa has to stay off until the electrician comes. Now what? With the power off there’s no Freeze Shield. For a long absence with “a risk of temperatures falling below 42.8°F(6°C),” the S400 manual says “we strongly suggest disassembling the spa and storing it” (p. 4). I’d treat a long wait the same way: power stays off, then drain, air-dry and store. The winterizing guide has the steps; skip its blow-out with the pump, since this pump stays unplugged.

Did your GCF or E18 turn out to be the outlet, the house wiring or the pump? Tell me what the electrician or Bestway found. Owner reports are how this page gets better.

Jake Weber — Jake Weber is the pen name of Rookie Spa’s editor. I don’t sell spas or chemicals, and I’m not affiliated with any brand. Every guide here starts from the manufacturer’s manual, is cross-checked against the questions and fixes owners report most often, and is written in plain English for first-time owners — with a clear warning whenever something involves electricity or water safety.