Flashing FLO still won't go...

[bucci man jr]

Howdy all -
I have a used 20-yr old Sundance Marin 850 that was installed over four years ago and runs normally - until last week.

Symptoms:
1. The dreaded "Flashing FLO" error.
2. The pumps all run.
3. I could feel heat coming from the area below the control panel.
4. It won't heat past the low 80F range.

What I've tried:
A. Replaced the Stage 2 filter. Didn't fix it.
B. Removed and sprayed off the Stage 1 (pleated filter). Made sure I didn't have air bubbles. Even ran the hose into either side of the filter opening. Didn't fix it either.
C. Ordered a Flow Switch and installed it tonight.
D. When that didn't fix it, I tried running the pumps for a couple minutes without the filter. Still no luck.

My Questions:
I. One thing puzzles me about the pic - even the old Flow Switch housing didn't have water full to the top. Is that indicative of a weak circ pump?
II. Before I order a circ pump and find out that's not really the problem...can anyone tell me how to conclusively diagnose it?
III. Or, is there one last-ditch thing I should try (that I haven't done already - see "What I've tried")?

Thank you!

 

[ajw22]

Welcome to TFP.

Let’s see what @RDspaguy thinks.

 

[JamesW]

When the pump turns on, does the paddle close to the stalk?

 

[bucci man jr]

"When the pump turns on, does the paddle close to the stalk?"

No, it does not, and neither did the old one. Hence, my question # I...is the level of water in the housing typical?
(Edit: the pic above was taken with both jet pumps running.)

 

[JamesW]

There should be no air in the lines.

When the pump turns on, does the paddle move at all?

Sometimes the pump can get airlocked.

Can you feel water moving when just the circulator pump is on?

Can you show the whole system?

Is the switch facing the correct direction?

 

[JamesW]

What model circulation pump do you have?

 

[bucci man jr]

Thanks JamesW -

Switch is definitely facing correct direction. Can't get you a pic of the whole system right now, sorry.
No, the paddle doesn't move any perceptible amount when the pumps are on.
Cannot feel water coming out of the return inside the spa, if that's what you mean.

Circ Pump model is:
Laing Circ Pump SM-909-NHW-18, 230 Volts, 65 Watts, 3/4" Barb size

Can you give me the best method to get the circ pump out of airlock? Would it be best to just drain completely and refill?

 

[JamesW]

Push water into the pump from the skimmer or vacuum the water through the returns with something like a shop vac.

 

[ajw22]

Can you give me the best method to get the circ pump out of airlock? Would it be best to just drain completely and refill?

Hot Tub Air Lock: How to Fix It Fast - Pool Care School

What do you do when your hot tub isn't expelling water from the jet? Read on to learn how to fix a hot tub air lock and get back to tubbin'!

poolcareschool.com

• You should fill the hot tub from the footwall or the filter canister. The water rises by pushing out the air since the water fills the lowest point first.
• When the water level reaches the desired point, you have to turn the jet on. This will further help to push out any air bubbles coming out.
• Check the bleeder valve regularly as well since they can help in preventing airlocks. You will have to open the valve near the filter cartridge and release the trapped air. Then, turn the power on to run the jets.

 

[JamesW]

Laing Circ Pump SM-909-NHW-18, 230 Volts, 65 Watts, 3/4" Barb size

65 watts at 230 volts should be about 0.28 amps.

Check the amperage that the pump is pulling.

Can you tell if the pump impeller is spinning?

You might have to remove the pump and open it up to check the impeller to see if it is spinning.

 

[RDspaguy]

On your spa the circ pump likely pulls from the main (jet1) pump pressure side, as the circ pump was an option at that time as I recall. The main pump should also push through the heater and flow switch. Turn on main pump and see if flow switch closes. If so, it's likely a bad circ pump. In this case, it will often heat during filter cycles. If not, you could have an obstruction or airlock.
The surest way to clear an airlock is to disconnect the hose on the circ pump and let it dump about 10 gallons from the heater side. The best way to avoid one is to fill through the filter pipe.
Circ pumps are a common problem, and are typically replaced every 3-5 years, though I have seen them last much longer in some cases. I recommend the 98w circ pump for Sundance.
Post pics of equipment area, circuit board, and wiring diagram. Do you have a multimeter?

 

[bucci man jr]

Thank you both! Sorry about my delay in replying; I had to pause on this until today.
Tried using a shop vac to pull air through; also tried loosening the coupling at the closest available jet pump (as suggested elsewhere). But it the coupling I opened must have been the wrong side; all I could hear was air getting sucked in - and no water came out.

@ajw22 - if there is a valve near the cartridge area on this tub, it's behind a panel that spans the width of the tub, so not really behind a service panel. I tried draining the tub from the slice valve below the spa pack, but that did not clear up the FLO error, either.

I gave up; drained and refilled the tub. This time I took special care to place the hose inside the filter area. I don't want to divert this thread from the main topic, but I really don't see the point of filling the tub this way, since the water all escapes the filter area and falls into the footwell. There is absolutely NO WAY to fill this tub in a fashion that prevents water from entering the foot jets first (see pics).

I also drained the Flow Switch housing using the smallest hose that connects at the bottom of it. (And yes - I verified that the Flow Switch sensor is pointing the right way, per the Sundance video on YouTube).

So when it turned on, I still have the flashing FLO error code. @JamesW - I was unable to clamp only the hot lead, so I could not tell how much current the Circ pump is drawing.

Also, I noticed that when the Flow Sensor housing *did* fill up with water, it filled from the small hose that connects from the bottom, rather than the 3/4" hose on the left (which comes from the heating element). Combined with everything else, this leads me to believe that I have a pressure problem and not an airlock problem.

Still hoping to avoid the purchase of a new Circ pump, I removed the run capacitor from it and tested it. It did not have continuity, and it charged / discharged on the 200k Ohms resistance setting. So the run capacitor appears fine.

I'm about to pull apart the Circ pump and look for impeller failures. But I'm wondering one more thing:
Do these Sundance Heaters have screens inside them? Or are these heaters known for accumulating buildup (especially on hard water) and preventing the correct flow rate?

Many thanks!

 

[ajw22]

Post pics of equipment area, circuit board, and wiring diagram. Do you have a multimeter?

 

[Methuselah]

If you remove the circulation pump to check the impeller, perhaps there's an electric motor repair shop near you that can change bearings, turn down the commutator and replace the brushes...

Several years ago I had this done to a $100+ motor for $4 or $5 bucks.

 

[bucci man jr]

Post pics of equipment area, circuit board, and wiring diagram. Do you have a multimeter?

Yes, have a multimeter.
Pics below. Circ pump that feed into the heater is pulled out of the loop so I can reinstall the run capacitor and figure out a way to see what its head truly looks like without being connected to the heater.
Wine corks make excellent temporary 3/4" hose plugs when the Vise-Grips+shop rag trick fails you!
@RDspaguy I can't get the Flow Switch to close even with both Jet Pumps running at full clip, and I cannot feel water coming out of the hot water return in the footwell.

 

[JamesW]

Get some vinyl tubing and connect it to the pump suction and return and then run the tubing into the tub to see if the pump is pumping.

Note: Don't do anything unless you are 100% sure that you can do it safely and correctly.

 

[bucci man jr]

I got some vinyl tubing and couldn't get the circ pump to move water, even after I primed it.

I found where the hot lead plugged into the board and clamped it while it was running - .49 Amps.

Either I got the run capacitor leads reversed when I connected it back to the motor - or something inside the pump is shot.

 

[JamesW]

The amps are too high, especially for not moving water.

The motor is probably locked or blocked.

I would open the pump and see if you can spin the impeller or if there is something in the impeller like hair or other debris.

 

[bucci man jr]

@JamesW - nothing jamming the impeller but I take it that heavy amounts of slop are abnormal? (That's a 3/16 hex wrench I've got in there to show how far it wobbles.)

 

[bucci man jr]

If you remove the circulation pump to check the impeller, perhaps there's an electric motor repair shop near you that can change bearings, turn down the commutator and replace the brushes...

Several years ago I had this done to a $100+ motor for $4 or $5 bucks.

I envy your availability to people who seem to machine for the love of it. In Cali, I tried to have that done on a pool pump motor, but the guy told me outright he'd charge me more than what a replacement would cost...