Spa/ Pool Heater Cycling.. Need Ideas

[ajw22]

20 PSI is more normal and what I would expect. You should only run the heater when the cleaner line is off so it gets enough flow.

Clean the flame sense line using a dollar bill.

 

[ajw22]

Put the MPV (multi-purpose valve) on your filter in RECIRCULATE mode and then run your spa and heater and see how it works.

 

[quinnstefanie]

that regulator steps the pressure down to

Looks like this, has a single wire running to it. Don't use sandpaper. Literally a newer dollar bill works great.
View attachment 467314

I will look for that and clean it with a dollar bill tomorrow. I will let you know. Thanks for the advice.

 

[ajw22]

Put the MPV (multi-purpose valve) on your filter in RECIRCULATE mode and then run your spa and heater and see how it works.

 

[quinnstefanie]

Put the MPV (multi-purpose valve) on your filter in RECIRCULATE mode and then run your spa and heater and see how it works.

I am trying it now.

 

[quinnstefanie]

I am trying it now.

Unfortunately, did not work on recirculate. Same behavior. cycling with service light. as the service light comes on, I hear a buzzing sound.

 

[1poolman1]

Unfortunately, did not work on recirculate. Same behavior. cycling with service light. as the service light comes on, I hear a buzzing sound.

Buzzing is, most likely, the spark ignitor trying to re-light the heater.

 

[quinnstefanie]

This picture is not great. I believe I see the flame rod located behind this. It has the one wire running to it as you mentioned. Do you have any advice on how to remove it? not sure what this part is in front of it.

 

[quinnstefanie]

This picture is not great. I believe I see the flame rod located behind this. It has the one wire running to it as you mentioned. Do you have any advice on how to remove it? not sure what this part is in front of it.

Here is another picture that I just took. The arrow points to what I think is the flame rod. Wondering how to get it off. Not sure what the part is in front and if I unscrew it.

 

[quinnstefanie]

That regulator steps the pressure down to less than .5psig (10" water column). Do the following first.

Looks like this, has a single wire running to it. Don't use sandpaper. Literally a newer dollar bill works great.
View attachment 467314

I went through the manual and can’t seem to find the flame rod on this model. does it have one definitely? I do not believe that is what is in the picture

 

[swamprat69]

You seem to have a Pentair MiniMax Plus with electronic ignition (Natural Draft). This should be the manual for your heater https://www.parts4heating.com/v/vspfiles/images/pdfs/MiniMaxPlusPowerMaxIG.pdf . What you have is an intermittent pilot with spark ignition. You have no blower, hot surface ignitor or separate flame sensor. Your ignition module should be a Honeywell S8600. If the heater runs for 10 mins. at a time before it shuts off there is a slight possibility that it is due to lack of flame sensing (drop out from weakened flame signal) and more likely that it is dropping out from a safety. If you have a multimeter and feel both safe and capable of using it, you could try to find the reason that the heater is dropping out by tracing back the circuit from the igntion module. When the heater is asking for heat, you should have 24V between the 24V (gnd) terminal and the 24V terminal on the Honeywell ignition module. If the 24V drops out when the heater stops, it should not be a flame sensing issue and you should be able to trace backwards from the ignition module with one meter lead on the ignition module 24V (gnd) terminal back through the circuit with the other meter lead using the wiring diagram on P21 of the manual. I did notice from your photos that there seemed to be some rust/corrosion between the pilot assembly frame and the pilot mounting plate in the burner assembly. Your heater probably needs a thorough cleaning. The flame for the pilot is sensed through the spark rod on the pilot assembly back through the pilot hood, pilot assembly frame, pilot mounting bracket and on to the heater cabinet ground. All these areas must be clean metal to metal connections. The part of the pilot assembly that has a wire attached to it is the spark electrode/sensor. The burners should probably be inspected and cleaned also. Would be happy to help you with any other questions you may have to the best of my ability.

 

[swamprat69]

Also the amount of corrosion/rust on the burner box floor plate and pilot line near the burner box could be an indication of either a heat exchanger blockage or moisture in the burner box or heat exchanger.

 

[quinnstefanie]

Also the amount of corrosion/rust on the burner box floor plate and pilot line near the burner box could be an indication of either a heat exchanger blockage or moisture in the burner box or heat exchanger.

Thank you very much for all this information. Very helpful. I have a multi meter and I am comfortable working with it. I am going to try to clean the entire pilot assembly and trace the volts first. It is good to know that the pilot assembly has continuous flame sensing which is a viable explanation.

Hopefully there are no issues with a burner box or heat exchanger due to moisture. I have noticed, very isolated, hearing a noise that almost sounds like a drip and sizzle. Maybe only once during operating. Not frequent. I assumed this was normal just because it has been wet outside and cold with condensation. I’m hoping it is normal and not the issue.

 

[ajw22]

Hopefully there are no issues with a burner box or heat exchanger due to moisture. I have noticed, very isolated, hearing a noise that almost sounds like a drip and sizzle. Maybe only once during operating. Not frequent. I assumed this was normal just because it has been wet outside and cold with condensation. I’m hoping it is normal and not the issue.

If cleaning the flame sensor does not fix it then I think you need to be prepared to replace the heater. It is over 20 years old and is past its use by date.

The sizzling is not a good sign and you may have a leaking heat exchanger.

Have you inspected the heat exchanger for scaling or leaks?

 

[quinnstefanie]

If cleaning the flame sensor does not fix it then I think you need to be prepared to replace the heater. It is over 20 years old and is past its use by date.

The sizzling is not a good sign and you may have a leaking heat exchanger.

Have you inspected the heat exchanger for scaling or leaks?

I will give the exchanger a more thorough inspection but I have not noticed any leaks from where I can’t see it.

A lot of the corrosion on the floor could also be a result of the fact that the backwash discharge is laid out to give the heater a bath. I have already bought some PVC to correct this before I backwash again. hard to believe it was left this way. I’m sure the pool chemicals are not good for the heater.

 

[ajw22]

As @swamprat69 said all that corrosion is not good for the way that heater uses grounds through the structure and the flame sensing. There comes a point where it is impossible to get all the grounds clean and working.

 

[1poolman1]

Thank you very much for all this information. Very helpful. I have a multi meter and I am comfortable working with it. I am going to try to clean the entire pilot assembly and trace the volts first. It is good to know that the pilot assembly has continuous flame sensing which is a viable explanation.

Hopefully there are no issues with a burner box or heat exchanger due to moisture. I have noticed, very isolated, hearing a noise that almost sounds like a drip and sizzle. Maybe only once during operating. Not frequent. I assumed this was normal just because it has been wet outside and cold with condensation. I’m hoping it is normal and not the issue.

Single blue wire is the "spark" wire. Your heater may use the pilot burner as the flame sensor the way RayPak does. It can be removed and cleaned as well, but requires removing the pilot tube from the gas valve so the whole assembly can be removed. Haven't worked on one of those in at least 10 years so its hard to remember all the changes Pentair made before discontinuing that heater.

There appears to be water dripping off some of the burners in the picture. Could be condensation, could be a leak.

 

[quinnstefanie]

Single blue wire is the "spark" wire. Your heater may use the pilot burner as the flame sensor the way RayPak does. It can be removed and cleaned as well, but requires removing the pilot tube from the gas valve so the whole assembly can be removed. Haven't worked on one of those in at least 10 years so its hard to remember all the changes Pentair made before discontinuing that heater.

There appears to be water dripping off some of the burners in the picture. Could be condensation, could be a leak.

OK. Was able to take this off and it is looking rough. The spark looks like it is burned. I am going to try to clean this first, then I will try to take the tube off if it doesn’t work. did not notice any dripping or accumulated moisture underneath. Hopefully we are still good. I will keep you updated.

 

[quinnstefanie]

OK. Was able to take this off and it is looking rough. The spark looks like it is burned. I am going to try to clean this first, then I will try to take the tube off if it doesn’t work. did not notice any dripping or accumulated moisture underneath. Hopefully we are still good. I will keep you updated.

 

[1poolman1]

The "hood" above the center wire (electrode) and the "fork" at the top of the assembly are the flame-sense portion. Yours is extremely dirty. Use a "Scotch Brite" type scrubber to try to get it back to shiny. You can use a dollar bill on the electrode. Clean the mounting surface as well. Interesting that you were able to remove the pilot tube, they are usually very stuck.

Along with the high-voltage spark a very small electrical current is sent along that blue wire as well. When the pilot lights the flame (which can carry current) completes the circuit sending the current to "ground" and telling the system to open the main gas valve and stay on. That much dirt can cause enough resistance, especially as the metal heats up, that the control "thinks" the flame has gone out and shuts the system down to start a new cycle.