Hi, long time reader, first time poster. I seem to be having an issue with my Pentair Mastertemp 250 heater. In getting everything started up and ran for the season, I noticed the fuse blown and have replaced it. After replacement there is still nothing lighting up on the membrane pad and no LEDs behind it on the control board to give me a fault code. The LED on the ignition control module is lighting up solid though. Accordingly, I know there is power to the heater but nothing functioning past that. Any suggestions on where to start in replacements or diagnosis? Thanks!
Pentair Mastertemp 250 - Electrical Problem
- Thread starter JMac09
- Start date
- Jul 21, 2013
- 54,788
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
The Fenwal LED steady on indicates a Internal Control Failure.
Do you have a multimeter and know how to use it?
You have the MasterTemp manual and follow the troubleshooting chart?
@swamprat69 may be of help when he wanders by.
The Fenwal LED steady on indicates a Internal Control Failure.
Do you have a multimeter and know how to use it?
You have the MasterTemp manual and follow the troubleshooting chart?
@swamprat69 may be of help when he wanders by.
Last edited:
Hi AJW. Yes, I have a multimeter and admittedly can stumble my way through its use but no expert.
- Jul 21, 2013
- 54,788
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
swamprat69
Well-known member
Please complete signature with full list of pool and equipment. Automation?? In looking at what should be your manual https://www.pentair.com/content/dam...p/manual/Manual-MasterTemp-472592-English.pdf , the only fuse that I see is at the firemans switch. Is that the fuse that you replaced? Transformer secondary does not appear to be fused.
Thanks you much. I got the signature and profile completed. No automation on the heater, just the basic set up. Correct, fireman’s switch and I agree, that’s the only fuse I can find. Given the transformer secondary is not fused, do think that may be shot? I can run multi meter tonight.
That's indicating a control fault.
How old is the heater?
Do you have the correct voltage selector plug?
Measure the input voltage.
What color is the plug?
Note: Do NOT randomly change the plug just to try it as that can seriously damage the unit.
Check all wiring to see if any is damaged or loose.
Mice love to chew on the wiring and make nests inside.
Are there any signs of mice or animals?
Is the gas valve switch "On"?
Is the external gas valve "On"?
swamprat69
Well-known member
Conflicting information. Not sure how the Fenwal led can be lit without 24 volts present. Also need to track down the reason that the firemans switch fuse blew. Intermittent direct short to ground ( frayed wiring )? Intermittent excessive amp draw exceeding fuse rating? The fuse should have protected the transformer.
James to answer your questions; heater is approx 8 years old. Using the red voltage selector plug, that's what it was originally set up with. Input voltage properly reading a bit over 240. No apparent mice damage. Yes both gas valves are on.
All that said, I walked through the trouble shooting guide above. Had 24 VAC at transformer secondary, had 240 between L1 & L2, had 240 at transformer primary and reached the step where I jumpered the firemans switch to start readings at that point. Fenwall buzzed a bit, red light control fault solid and after taking further readings for a bit control board started smoking. It is clearly shot. I'll need to replace it, does anyone have a recommendation on where best to source this as its a bit price versus other heater parts?
Should I have any concern there is more of an underlying problem that as soon as I plug a new control board in that it'll end up just frying the new one?
Finally, given the cost of repair and the age of my heater, thought I'd ask, how long do these heaters normally last? Just making sure I'm not better to just replacing the whole unit if its about ready to Crud out further given the age.
All that said, I walked through the trouble shooting guide above. Had 24 VAC at transformer secondary, had 240 between L1 & L2, had 240 at transformer primary and reached the step where I jumpered the firemans switch to start readings at that point. Fenwall buzzed a bit, red light control fault solid and after taking further readings for a bit control board started smoking. It is clearly shot. I'll need to replace it, does anyone have a recommendation on where best to source this as its a bit price versus other heater parts?
Should I have any concern there is more of an underlying problem that as soon as I plug a new control board in that it'll end up just frying the new one?
Finally, given the cost of repair and the age of my heater, thought I'd ask, how long do these heaters normally last? Just making sure I'm not better to just replacing the whole unit if its about ready to Crud out further given the age.
It's a gamble to buy an expensive part for an old heater.
If it works for a few years, you win.
If not, you have to spend more money chasing the next problem or cut your losses and buy a new heater.
Without knowing the condition of the heater, we can't really tell whether or not it's worth buying the new part.
Maybe some pictures would help.
If it works for a few years, you win.
If not, you have to spend more money chasing the next problem or cut your losses and buy a new heater.
Without knowing the condition of the heater, we can't really tell whether or not it's worth buying the new part.
Maybe some pictures would help.
Thank you, James. I ended up finding a used one on eBay for $225 from a reputable buyer with a money back guarantee. That was a much easier pill to swallow. Fingers crossed
- Jul 21, 2013
- 54,788
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Good luck.
Pentair MasterTemp Heaters - Further Reading
www.troublefreepool.com
Beware of Non-Pentair Boards
Control Boards for the MasterTemp are being sold on eBay and Amazon that are not Pentair OEM. Some are from Swimables. We have had two reports, here and here, of these boards not working.The clone boards have very different components and lack all the Pentair labeling on the board.
Good Evening, all. A bit of an update and a request for additional advice. I'm in a bit of guess and test mode but it seems to be progressing one part at a time. I replaced the circuit board. Upon replacing this, the membrane pad now comes on but nothing else so I replaced the ignition control module (ICM) next. After replacing the ICM the blower now comes on but not getting ignition. It attempts to light 3 times hearing a click each time for the count. Upon the third click the ICM flashes three times a handful of times then stops, service heater light comes on and shuts down. In response to this I replaced the less expensive parts as they all looked aged with corrosion; pressure switch, thermistor, automatic gas shutoff switch, high limit switch and ignitor. no change after any of these changes. Any sense where to go from here?
You bet. What pictures might help? Everything visually looks the way it should so not sure it’ll tell anything
- Jul 21, 2013
- 54,788
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Have you checked the gas pressures at the gas valve?
What is the condition of the gas valve?
Pics of the gas line, gas connection and gas valve.
Pics of internal wiring.
What is the condition of the gas valve?
Pics of the gas line, gas connection and gas valve.
Pics of internal wiring.
