StaRite MaxiTherm SR400LP Code and Spa Level Question

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T

towney

0
Apr 5, 2007
84
Central Florida
Tonight my heater was cycling on and off with error code of 128 r=5 code showing, any ideas? I seem to remember the last couple time this happened it was I believe the high limit switch or thermal switch. Can anyone also give me a walk thru on replacing what ever it might be.
On another note I have also noticed that when the spa and heater is turned on I'm seeing about 2 inch drop of water out of the spa, with the spa off and in pool mode water level is A'ok. I have checked all the auto valves for leakage and good there. Any ideas
See my sig for any additional info. Thanks
 
http://www.pentairpool.com/pdfs/MaxEThermOM.pdf

Does the heater start (heat up) and run fine for a few minutes then shut off?
Does the blower operate?
Which of the red diagnostic LED's are on?

It could be the fuel supply, pressure switch (PS), high limit switch (HLS), automatic gas shutoff (AGS), stack flew sensor (SFS), or thermal regulator.

Verify the proper flow rate of water for your heater. The model 400 needs a minimum flow rate of 40 gpm.

With an error code of E05, first check the fuel supply, next the SFS and finally thermal regulator.
If SFS LED is on then it could be the sensor itself or the thermal regulator.
Disconnect the stack flew sensor and test. It should have a resistance of 3.5 to 4 mega-ohms.

If Exhaust Gas temps > 450 and SFS is ok then next check the Thermal Regulator.
On the left side of the water manifold is a plug. Behind this plug is an o-ring, spring, and Thermal Regulator.
The Thermal regulator looks like a thermostat used in automotive applications. It should open at about 120 degree F.

Should you suspect the thermal regulator, it may be advisable to replace the spring and o-ring as well.
Thermal regulator kit includes the o-ring, spring, cap, spring clip and regulator and is only a few dollars more.

There are several experienced service techs on this forum. Hopefully someone can guide you through the diagnostic checklist.

** Information in this thread is based on diagnostic information provided by the manufacturer**
** I do not own this equipment, nor am I a factory trained service technician **

Pentair
Customer Service and Technical Support (8 A.M. to 5 P.M. Eastern Time/Pacific Time)
Phone: (800) 831-7133
 
Starts up fine and runs/heats for about a few minutes before it cycles off. Flow rate is good, propane is at 80% and blower is working. I have had this issue twice before and if I remember it was either HLS or PS. The heater will heat up the water but continues to cycle on/off every few minutes. Thanks
What am I looking for with respect to the LED light?
 
Poolschoolgrad said:
There are red diagnostic LEDs on the back of the board. (AGS, AFS, SFS, HLS, PS or THERMISTOR) are any of these on?
Click to expand...

I will check the board tomorrow and get back to you. Thanks again. The Tech I use charges 80 bucks service charge plus what ever else. This same issue has happened twice in the last couple years. By the way what's the r=5 (not r05) code that shows up after the 128 code?
 
Service techs from pool stores are $80/hr here also.
Independent techs charge $65/hr.
In most cases they are worth every penny. Especially on a pool heater. :)

Do you have a way to test the exhaust gas temperature? Infrared thermometer?
It should be around 250 F, but if you see temps in the 450-500 F range then the problem may be more than a bad sensor.

Current firmware as of 2008 from Pentair uses error codes like r05.
Previous firmware from Sta-Rite may use a different format like r=5. You could contact Pentair to be certain.

Code r05 on the board indicates dangerously high temperatures in the system and the system shuts down.
This could be caused by something as simple as a faulty sensor or by a true overheating condition.

Just because the last two times this happened it was the result of a faulty sensor, one should not immediately jump to the conclusion that it is a bad sensor. The diagnostic LEDs and the exhaust temperature will help determine the correct plan.
 
Thermal regulator operates the same as a thermostat in automotive applications except it opens at about 120 degree. You could place it in a pan of hot (>120 F) water to verify that it will open.

If output water temps are normal and exhaust gas temps are normal and there is no evidence of blockage, then this may be a control board issue. :cry:

However, before you spend the $$$$ for the control board, please contact
Pentair
Customer Service and Technical Support (8 A.M. to 5 P.M. Eastern Time/Pacific Time)
Phone: (800) 831-7133

Suggested retail on these boards is $695. They are available on-line for much less.
 

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r=5 would be the software revision of the board (revision 5)

E05 would be a stack flue sensor error (exhaust temp sensor), either too high too low shorted or open

Do as poolschoolgrad suggested and test that regulator, that sounds like the real issue.
 
Thanks poolschoolgrad for all your timely help. I put the regulator in close to boiling water and it does not open, so looks like this is the issue. Since I already have the tech coming out tomorrow I will direct him to this first, he's also doing some warranty work on my solar also. I will report back after the service call to give the final diagnosis for future reference. Thanks again.
 
Hope it is only the Thermal Regulator as the repair would be relatively inexpensive. :goodjob:

If possible, could you ask the service tech specifically about the error code 128 and the LED #11.
There is nothing in the current Max E Therm documentation about this code or this LED.
 
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