Need some help with my sta-rite 400na pool heater, when I turn on the power the computer board comes on with 888 then go's to 180 then r 4, then to the pool temp, I have replaced the HLS, AGS, THERMISTOR. The blower doesn't come on, and on the back of the mother board the HLS light is on. Does anybody have any idea on what I need to do from here?

Follow the wires from the board to the switch. Those heaters, and their wiring seem to attract mice/rats. You may just have chewed wiring.

Checked, wires are good.

There are 2 High limit switches.

I would check the pressure switch

Both have been replaced.

I too would verify the pressure switch is closing when the filter is on.

Had a heater tech out today, he replaced the Ignition Control Board, and still could not get the blower to come on, checked for power to the blower and no power to the blower from the board. He said that the computer board might be blocking a signal, he told me to buy a new heater, or a Control Board for $300.00. Scratching my head again. The r 4 code still comes up, does anybody know what that code is for???

Got the blower to come on, but still have the HLS light on at the computer board. I bypassed the thermistor and the service heater light stayed out, spa on light is on, display reading is now 126, and the HLS light is out and the R4 code comes up. None of the Membrane pad keys work. What next ???
Thanks

Edit: Wrote this before i saw your post above (5:45) You may want to read the next post first.

r4 is good, it's the firmware revision, and not a trouble code.

Did the HLS light come on for the tech.? And if it did, what happened when he jumped the high limit switch (HLS)?
Did the guy confirm the HLS was closed?
Dumb question: You mentioned that you replaced 3 items. Were these all new, out of the package? Or flea market/E-bay?

I would say, if you can find the two pins that connect the HLS to the main board, jump them, and the light stays on, it's the board.

Before you do this test, make sure to disconnect power from the heater (best way is at the breaker), locate and jump pins, turn on breaker, and give heater a call for heat. If the blower starts, there is a disconnect between those two pins (wiring and or HLS switch).


Buy a new $2000+ heater, or a $300 board? Hmm... How old is that one?

As your looking at the underside of the board encloser, Notice the ribbon cable coming out from behind the board, and plugs into it. That is for the touch pad. Cut power to the heater, and disconnect the ribbon cable from the board. Un short the thermistor. Turn on power, and see if that fixes it... not the touch-pad, but the heater.

Thanks will try in the morning.

I still see you have not replaced the pressure switch. Just had a similar problem with micro switch that was bad on the pressure switch. Jumper the two wires and try it

HERE IS AN UPDATE,
First disconnected the ribbon cable, then jumpered the HLS at the mother board, jumpered the fan, heater fired up and ran for about 3 mins, then the ASG light came on, and the unit shut down.
Tried to jumper that also but couldn't get it to fire again. Jumpered the pressure switch and still no go. Plugged the mother board back in and tried it again and still would not fire, all the mother board lights came on. Some pool tech at the pool supply store said that I can keep throwing parts at it and I still might not find the problem.
Real close to giving up.

You need to get a sharp guy out there this time, someone who can tell you with certainty that the parts you need are going to fix it! Maybe since you have paid that guy already you can discuss with his boss that a service call consists of more than "you either need a new board, or a new heater" I mean, what kind of diagnosis is that? If you buy a board from him and that does not fix it, he is going to want you to still pay for it right?

Thats not good service.

I don't remember having that many apparent intermittent failures with a heater at the same time. That kind of twitchyness might suggest the circuit board, but didnt you say you replaced that? Did you replace the main board? Or the ignition control box?