I've been chasing an SFS LED problem for two years. The heater fires and runs for 30-90 seconds, then quits with SFS LED lit. I used to be able to reset via automation and eventually the heater would get through this early shutdown and run all day, but now it never makes it through the initial 0-90 second period. When the problem first occurred two years ago, I replaced the sensor with an aftermarket and the problem didn't get better, but I limped along. Now that limping no longer works, I've replaced with a Pentair sensor and still have the problem. Sensor temp spikes to high 400s. I've tried most of the solutions on this forum short of complete dismantle to check for soot. Finally, I unscrewed the sensor and left it out and the heater ran fine. Meat thermometer spiked to 390 and settled to 350. I feel like I've isolated this to the SFS sensor/circuit by removing it and running the heater. I'm sure it's a bad idea to run the heater long-term without the sensor, but how many must I buy to get a good one? I feel like if I could just get past that initial spike, I'd be fine. Is there a way to increase the SFS temp trip level or add a delay into the trip function? Separate question: Does the firmware or software version of the heater ever need to be updated and how can I do it?
Pentair Mastertemp 400 SFS Error - Run Without Sensor Installed?
- Thread starter Murray1723
- Start date
- Jul 21, 2013
- 53,990
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Have you checked the internal bypass valve in the manifold? Replaced the Thermal Regulator?
Here is what the normal exhaust temperature should be:
Does your heater have a 5 button keypad or 6 button keypad?
Here is what the normal exhaust temperature should be:
- Below 250 degrees...very low
- 250 to 290 ..................low
- 290 to 350.................acceptable
- 350 to 480 ..................high
- Above 480...................error/shutdown.
Does your heater have a 5 button keypad or 6 button keypad?
Five button (Old). I should clarify that the SFS may be doing its job properly and the exhaust temp is truly exceeding the threshold for a short time during ramp up. But I think it would settle below the threshold if given enough time. What other than soot buildup would cause this initial exhaust temperature spike that eventually settles below the threshold? My water flow is good, chemistry has never been a problem, no airflow blockages, just replaced thermal regulator, and visually confirmed manual bypass valve spring and plate are intact. No water came out of bottom manifold bolt holes. No rodent damage. I have no external bypass, so whatever pump GPM shows should be flowing through heater I believe. I will say that the control board display is a bit flaky, but removing and reseating the ribbon cable resolves the problem for awhile. I use automation, so don't need control panel except to debug.
- Jul 21, 2013
- 53,990
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It sure sounds like you have a water flow problem at startup with everything cold with water not getting into the heat exchanger to absorb the heat. Instead the heat goes out the exhaust.
The thermal regulator and bypass valve in the manifold manage the water flow into the heat exchanger.
Did you test your new thermal regulator and confirm it opens in water at 120F?
If you have not pulled off the manifold and visually examined the tubes, bypass valve, and manifold condition, I would do that.
The thermal regulator and bypass valve in the manifold manage the water flow into the heat exchanger.
Did you test your new thermal regulator and confirm it opens in water at 120F?
If you have not pulled off the manifold and visually examined the tubes, bypass valve, and manifold condition, I would do that.
I ordered a new manifold bypass valve. I'll install it and check the thermal regulator function and seating when I have the manifold off.
- Jul 21, 2013
- 53,990
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Check the stack flue temperature sensor with a good ohmmeter while the sensor is cool. It should read 3.5 to 3.8 megaohms.
Check the SFS Temp to see if it reads correctly before the heater fires.
Get a 3.5 to 3.8 ohm resistor and connect it to the SFS wires to see what the SFS temp is with the resistor.
You can use several resisters in series to create the correct resistance.
For example, (3) 1.2 MOhm resistors plus a 200 kohm resistor in series creates 3.8 MOhm of resistance.
Do not operate the heater without a correct SFS sensor.
The above is only to test while the heater is not running.
Get a 3.5 to 3.8 ohm resistor and connect it to the SFS wires to see what the SFS temp is with the resistor.
You can use several resisters in series to create the correct resistance.
For example, (3) 1.2 MOhm resistors plus a 200 kohm resistor in series creates 3.8 MOhm of resistance.
Do not operate the heater without a correct SFS sensor.
The above is only to test while the heater is not running.
Last edited:
Pentair Mastertemp Stack Flue Sensor failure
So I have a new (this season) Mastertemp 200. Ran great all season until a few days ago when I got home, and despite the heater being "on" all day, the pool was still cool and the heater wasn't running. E05 error. I could watch the SFS temp climb from ambient to approx 290º. It would hover...
www.troublefreepool.com
The sensor may be tested with an ohm meter (3.8 MegOhms @ 77F) If you decide to get a new SFS, check the stack flue temp when you get it back together and running to confirm that the stack flue temps are where they should be, and not too high.
If you have a 3.8 MegOhm resistor connected to the heater SFS terminal, it should read 77 degrees from the control panel.
If you have a 3.8 MegOhm resistor connected to the heater SFS terminal, it should read 77 degrees from the control panel.
The thermal regulator is a blind insertion. As far as I could feel, the new part seated properly. When I pulled the manifold, however, I could see it was not seated, and in fact it COULD NOT seat properly. I don't know if it was fab'd too wide or if it got smashed down somehow, but it broke when I tried to bend it to fit. It was a pain to assemble the spring to the regulator and get the clip seated/bent properly, so maybe I damaged it in that assembly process. Also, it didn't start opening until 160 degrees and didn't fully open until 210 degrees. Amazon indicated this was a Pentair part, but I question whether it really is. New part is on order and this one is going back. Glad I bought that new manifold bypass and gasket kit I probably wouldn't have needed if this part had fit properly.
Received a second thermal regulator that is too large for the manifold hole. What would go through the manifold hold is a little fatter and shorter. I'm now wondering if the manifold has changed since my pool was installed in 2018. I do have the old style touchpad, so maybe the manifold changed as well? I'll chase down a Pentair thermal regulator from the official dealer this time.
Attachments
- Jul 21, 2013
- 53,990
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I didn't think the two I've tried were knockoffs, but I got an official Pentair part from the local carrier and it fits. I'll add appropriate comments on Amazon. Now I've replaced everything and I get an immediate E06 error following the keypad boot-up codes with the SFS LED lit. Blower doesn't come on at all. I'm chasing stack flue sensor circuit now hoping it's not a bad circuit board.
- Jul 21, 2013
- 53,990
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
From Pentair MasterTemp Heaters - Further Reading
An E06 is a shorted sensor, or if the board thinks it is a switch, and not a thermistor (didn't get programmed when it was installed).
Pentair tech support suggests testing their new ones before installation. The sensor can be tested with an ohm meter (3.8 MegOhms @ 77F)
If you have a 3.8 MegOhm resistor connected to the heater SFS terminal, it should read 77 degrees from the control panel. Get a 3.5 to 3.8 ohm resistor and connect it to the SFS wires to see what the SFS temp is with the resistor. You can use several resisters in series to create the correct resistance. For example, (3) 1.2 MOhm resistors in series creates 3.6 MOhm of resistance.
Do not operate the heater without a correct SFS sensor.
The above is only to test while the heater is not running.
If you are replacing a failed Stack Flue Sensor, your Control Board should be set correctly for the new one. However, if you are replacing either an Outdoor Stack Flue Switch or an Indoor Stack Flue Switch, the Control Board will need to be reset as follows:
An E06 is a shorted sensor, or if the board thinks it is a switch, and not a thermistor (didn't get programmed when it was installed).
Pentair tech support suggests testing their new ones before installation. The sensor can be tested with an ohm meter (3.8 MegOhms @ 77F)
If you have a 3.8 MegOhm resistor connected to the heater SFS terminal, it should read 77 degrees from the control panel. Get a 3.5 to 3.8 ohm resistor and connect it to the SFS wires to see what the SFS temp is with the resistor. You can use several resisters in series to create the correct resistance. For example, (3) 1.2 MOhm resistors in series creates 3.6 MOhm of resistance.
Do not operate the heater without a correct SFS sensor.
The above is only to test while the heater is not running.
Stack Flue Sensor Control Board Setup
The Control Board is designed to work with both the Stack Flue Switch (on older heaters) and the Stack Flue Sensor (newer heaters). Please see Figure 2 to identify which type of Stack Flue protection you are replacing.If you are replacing a failed Stack Flue Sensor, your Control Board should be set correctly for the new one. However, if you are replacing either an Outdoor Stack Flue Switch or an Indoor Stack Flue Switch, the Control Board will need to be reset as follows:
- Turn the power to the heater ON.
- Press and hold the OFF button on the membrane pad until the 3-digit display shows “Ad0” or “Ad1” (about 10 seconds).
- Release the button and then press it momentarily. The 3-digit display will now show either “SF0” or “SF1”.
- If the display reads “SF1”, it is correctly set. Go to Step 5. If it reads “SF0”, use the arrow buttons on the membrane pad to set it to read “SF1”.
- Momentarily press the “OFF” button to exit the program.
I jiggled the wire connectors at the Stack Flue Sensor back and forth a few times and E06 error went away. Apparently corrosion was interfering with the connection there. But now I'm back to where I originally started. The burner runs for 15-20 seconds until the exhaust temp exceeds 450 and shuts down. I replaced the thermal regulator with one that fits and functions per hot water test and replaced the manifold bypass valve and all the o-rings. I'm getting good water flow according to my pump output. So I don't think the problem is on that end. I'll check my 3 Stack Flue Sensors with a meter to make sure they're not the problem. Assuming they're not, I'm going to work on the sooted heat exchanger theory. I don't know what else it could be. Has anyone ever stuck a vacuum hose down the exhaust pipe to see what comes out? Is there any potential harm in trying that before I tear apart the whole heat exchanger?
- Jul 21, 2013
- 53,990
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I replaced the manifold bypass valve located inside the manifold. It wasn't bad as far as I could tell, but I had a new one and decided to replace it while I was in there since it's 6 years old. Also, the heater exchanger coils were not blocked with lime buildup and no water leaked out out the bottom two manifold screws.
- Jul 21, 2013
- 53,990
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Simply the SFS error is saying the heat is going out the exhaust instead of being absorbed by the water.
The problem is water flow into the heater, water flow through the manifold, water flow through the heat exchanger, or soot on the exterior of the heat exchanger not allowing heat to be absorbed by it. Your challenge is figuring out which one it is.
The problem is water flow into the heater, water flow through the manifold, water flow through the heat exchanger, or soot on the exterior of the heat exchanger not allowing heat to be absorbed by it. Your challenge is figuring out which one it is.