EO5 Stack Flue Sensor on a Pentair Mastertemp Heater - How to fix it

Pentair Pool Quick Link for Parts/Equipment: amzn.to/3q6MXmf Mastertemp Pool Heater Parts: amzn.to/391FMio
Heaters are really important in Michigan here Mark talks about Error Code EO5 and how to go about fixing this heater, or how to problem solve.
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[@DordiHOTS]

Thank you so much. I was getting E05 shortly after the heater started heating (approx. 30 seconds). After I replaced the stack flue sensor, the issue went away. A couple of things to note to fix E05: a) the main circuit board located under the control board membrane should be cleaned, you can unscrew the 4 screws of the board and clean it. You have to disconnect the membrane connector on the left by pulling it CAREFULLY. b) the air blower needs to be cleaned thoroughly, there is an inlet and it should be cleaned of leaves and debris. c) the entire heater should be cleaned from debris and leaves. Especially on open contacts above the igniter near the gas which could cause a short circuit and an electrical explosion with gasoline. This is the most important thing to clean. d) the stack flue sensor should be replaced by a Pentair factory part (Pentair 77707-0010 Thermal Regulator). Make sure you buy a factory OEM part otherwise the connectors might not fit. Poolandspasupply has the OEM part. e) the Pentair 77707-0010 Thermal Regulator should also be checked as this can be related to E05 or E06, it is located outside the enclosure between the water inlet and outlet. You can use a flathead screwdriver to release the spring loaded regulator and investigate it for corrosion. f) all of the electrical connections should be checked for corrosion, and short circuits between contacts. Spiderwebs, dirt, leaves or debris can cause electrical hazards which is why a thorough cleaning and vacuuming is necessary. How to check if the Pentair Stack Flue Sensor 42002-0024S is bad: 1) Using a multimeter, set the device to resistance testing mode (The icon looks like a horseshoe). 2) Put each multimeter prong on the stack flue sensor terminals. If the resistance measures 0 it is bad, replace the stack flue sensor. 3.5 ohm or higher means the sensor is working.

[@jonhays8124]

Great video! This saved me at least a hundred dollars by not having to call someone out, THANKS! It would have been great to get an angle on the video looking into the heater to see the sensor, but it was still easy enough to find. I bought my sensor on amazon for 22 dollars and the replacement took about 10 minutes. Thank you very much

[@Askthepoolguy]

Great- glad it helped!

[@kreader50]

Awesome video I checked my Flue sensor after seeing your video. I checked the wires and they were okay. I pulled on the wires where they connect and pushed them back into the socket and it started working. My heater sits out in the weather and we had some serious rain the other day. I am wondering if some water got in to where the wires connect. Thanks for sharing

[@pfactor5201]

Thank you for a very informative video. Short and sweet, cut to the chase.... Thank you

[@Askthepoolguy]

You are welcome!

[@tradermactrade7242]

Hey Like your video's. My panel stopped working years ago but now my HEATER stopped firing and have no codes to read. so I replaced the STACK FLUE SENSOR the IGNITER AND NOW the IGNITION MODULE and still no firing of heater? NONE of the parts were bad so I'm baffled. NO ignition now and it ran perfect for 10 years. Any ideas?? I've hared about a ignition lockout but no idea where to find it.

[@carlosfarias4008]

Amigo tengo un problema con el pentair 250 error r13 me podría a a yudar

[@richardmeszaros3421]

OK, I had code eo5, replaced stack flue sensor, and still have code eo5, board read out flashes 40 80....now what can I check?

[@Askthepoolguy]

If you don't have a pool guy available to ask- Pentair has several codes on their website to track through - and their customer support line is also handy...we will try to address this question in an upcoming video for future viewers as well!

[@enriquedosterjr.3367]

Richard, I had the same problem. Were you able to fix it?

[@psantini5963]

You can check sfs , with a meter . Reading should be around 3.5 mega ohms . If it reads good you have a bad control board . Remove the board and follow traces for the 2 white wires . The 4 th pin on my board to a spot on the board was open . Soldered a wire jumper in place of the open trace . Back in business . Saved 500 bucks vs pool repair tech

[@ciceromuniz6020]

good evening! I'm Brazilian I have mastertemp to LPG gas. which is consuming a lot of gas. Can you help me?

[@Askthepoolguy]

Hello - if you are using a lot of gas you may want to try a solar cover, either a physical cover or the liquid solar blanket to prevent evaporation of your water when it warms up. Also - check your system to make sure you don't have a gas leak - and make sure your gas line is sized appropriately to your heater size. A mis match between the gas line input and the amount of gas the heater needs can cause an issue.

[@OliverLeveritt]

I was getting the E05 code, so I Googled it and came here. I went back out to the heater unit and wondered if the big ass grass (that stuff that grows 6 feet tall) was causing a problem. It was spread out to within about 6" of the exhaust. I got my trusty Ryobi One+ hedge trimmer and cut that stuff back about two feet. Problem solved.

[@Askthepoolguy]

Landscaping that grows up around the heater is a very common issue, and often overlooked by homeowners...glad you caught it!

[@gmonyy1]

So I replaced the sensor and it didn't solve the issue. What else could it be? The circuit board, maybe?

[@DordiHOTS]

Check the fuel supply, thermal regulator, resistance of the stack flue sensor (should be 3.5 ohm or higher), obstructions in the exhaust flue or air blower, or shorts from cobwebs on the circuit board.

[@wsohl]

Probably should show video of where the sensor is.

[@Askthepoolguy]

Great idea - watch for this in a future video!

[@douglasfritz7944]

My heater will heat for about 10 minutes then shut off for a bit then back on and off. Any suggestions?

[@douglasfritz7944]

No error codes, or flashing lights under the control panel. Did notice wires going into heating chamber had insulation missing

[@pvt-pilot]

If you have no error codes and no diagnostic lights illuminated on the back side of your contol board, then it sounds like a bad thermal regulator. I would suggest removing it and testing it and replacing it if necessary. Watch my video here if you need help with that: kzbin.info/www/bejne/aXa1nnh-nZ19Z9U The purpose of the thermal regulator is to open up at temps exceeding 120° which will let cold water into the output side of your heater manifold in order to dilute the superheated water heading to your spa. This is a justified safety designed to prevent scalding a user sitting by a jet and also prevent melting a hole in your underground plastic PVC plumbing heading to the pool from the heater. The contol board can detect this unsafe scenario due to the presence of the HLS (High Limit Switch) which is located on the bottom left side of your manifold (output side) Hope this helps.

[@chengkhang2804]

whats the error code?

[@tradermactrade7242]

should have mentioned it's a mastertemp400

[@torymblue2000]

Actually this doesn't show much at all :) How to test, check resistance on the sensor (yours is obviously bad, but bet most don't have their wires torn off). What is a good resistance when brand new, maybe what the resistance is when it's at temp..

[@DordiHOTS]

3.5 ohm is the proper resistance for the stack flue sensor on the Pentair MasterTemp models. Anything higher is also OK. When the sensor is bad, it will likely read 0L for the resistance.