I have a Pentair Minimax nt400 that I have replaced the control board twice because of rats. this last time I replaced it with a new one because the control board went blank. no lights nothing, dead. I bought a new board and replaced it, and nothing. No LEDs nothing, dead. I have the 24v going to the board. I plan to replace the power transformer next. But is there a fuse inside the heater, other than the on/off switch, that i can't find?
MiniMax Nt 400 control board dead
- Thread starter jsc65elco1
- Start date
- Jul 21, 2013
- 65,727
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
Rats can trash a heater. You probably have some wires they chewed on broken.
I doubt replacing the Power Transformer will fix it if you have 24V output.
Let's see what ideas @swamprat69 has.
Rats can trash a heater. You probably have some wires they chewed on broken.
I doubt replacing the Power Transformer will fix it if you have 24V output.
Let's see what ideas @swamprat69 has.
I replaced the boards after I fixed the chew wires. It's a new board , all seems ok but no lights on board
- Jul 21, 2013
- 65,727
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I suspect you missed a wire.
How corroded is the insides of the heater from their urine?
How corroded is the insides of the heater from their urine?
swamprat69
Well-known member
Does this look like the manual for your heater? https://www.tiledspas.com/images/Other/Heaters/MiniMax_NT_man.pdf You say that you have no lights, but have 24V at the board. Are you measuring 24V at the P4 connection to the board? If so, are you also able to measure 24Vbetween the "24VAC" and the "GND" terminals on the Fenwal ignition control with P4 connected to J4 at the board?
replaced transformer and seems like I got control board to light up. Now it shows a "LO" on the board . If set the pool on , fan runs but no sign of heat?
Replaced transformer.and board lights but has a "LO" message. What does that mean? Set pool to 85 degrees and only fan comes on . No heat.
- Jul 21, 2013
- 65,727
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Show us pictures of your heater and the LO message.
Hayward heaters have an LO code. Pentair Minimax heaters don't have a display panel to show codes. They have LED indicator lights.
Hayward heaters have an LO code. Pentair Minimax heaters don't have a display panel to show codes. They have LED indicator lights.
first picture is heater board on, power light on. second picture is spa heat on, power, pressure switch, and thermostat lights on. Fan runs but no heat . third picture is after five minutes, fan motor shuts off power, pressure switch, and thrmostat lights on along with sevice lights and E04 code.
Attachments
- Jul 21, 2013
- 65,727
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Finally found the manual that shows your heater controls - https://www.bing.com/ck/a?!&&p=fc09...WVzJTIwSW5zdGFsbGF0aW9uJTIwR3VpZGUucGRm&ntb=1
You have a Pentair MiniMax NT LN model. Pentair made a bunch of MiniMax heater models with different control panels.
LO is Water temperature below 58F. See page 25.
E04 is a Fan Failure. Page 28.
Have you opened up the heater to check that no critters nested in it?
Check the blower for any debris or blockage.
You have a Pentair MiniMax NT LN model. Pentair made a bunch of MiniMax heater models with different control panels.
LO is Water temperature below 58F. See page 25.
E04 is a Fan Failure. Page 28.
Have you opened up the heater to check that no critters nested in it?
Check the blower for any debris or blockage.
Yes, I understand that the temp is below 58 deg. but heater does not fire up to heat it up. And yes I have checked the fan compartment, all is clear. Fan area is clear. I had this code the first time I replaced the control board, it worked good for about 1 year.
Pentair MiniMax digital control and display board. LO can mean that the temperature is outside its range or that the water is too cold for the heater to light without damage to the heater (condensation).
Outside touchpad:
Last edited:
- Jul 21, 2013
- 65,727
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It is probably not the board.
Check the air pressure switch.
Check the tube from the guan to the switch is intact.
Use a multimeter and see if the switch closrs when you gently blow into the tube and opens when there is no airflow into the tube.
The board is brand new, the ignition module is new and the pressure switch is new. I've checked all this. As I stated before, the fan starts up but it never fires up to heat.
- Jul 21, 2013
- 65,727
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Just because things are new does not mean they work.
Do you have a multimeter and know how to use it?
It takes some diagnostics using a multimeter to find where the safety sensors are not allowing ignition. The manual explains how the safety systems and ignition sequence works.
Do you have a multimeter and know how to use it?
It takes some diagnostics using a multimeter to find where the safety sensors are not allowing ignition. The manual explains how the safety systems and ignition sequence works.
Where are the pictures? Does it display LO? That means the board is working. If so the heater may not light as the water is too cold. If that is the case, sometimes just keeping the water moving for a while will warm it to the point the heater will fire.