Minimax NT400 Pool Heater problem

[Canadaguy1]

When I select Pool on the Temperature control panel the fan will run. I get no voltage on the ignitor terminal on the ignition module. After about 50 sec. I do get a 26 volt reading at the gas valve but it only lasts for about 5 seconds. I'm assuming this is because I'm not getting any ignition. It appears to go through the cycle several times and eventually shuts down giving an error message of E-04. Indicating a fan problem ...but the fan runs fine.

I have already replaced the temperature control board, which was obviously defective, and I was thinking that the ignition control module may be gone as well because I can't get the 120v reading at the ignitor terminal on the module. What else could cause not getting the required 120v reading at the ignitor terminal on the ignition module.

Thanks in advance for your assistance.

 

[ps0303]

E04 does indicate fan problem but that fan/blower is connected to an air blower switch. Check to make sure the air tubes are intact and haven't been chewed by a mouse. If they look good, then I would check the blower motor and make sure the squirrel cage is intact and not rusted out. Many times the cage is rusted out but you can still feel some air blowing out the top exhaust. If all of that is good, I would then suspect the air switch. This can be bypassed but you have to do it at the correct time during the firing sequence. But first check the air tubes and the blower motor.

 

[Canadaguy1]

I've taken the top off the unit and I'm only seeing 1 tube and that is in good shape. The fan and the fan housing are good. All wire connection under the hood seem to be good. i took the tube off the fan housing and sucked on it to see if I could hear the vacuum switch but could n't hear it operate. Maybe because of surrounding noise. I tried to run it through a sequence again with a hope of engaging the vacuum sw manually but now I'm getting an error message on the Temperature control module and it will not activate at all.

 

[ps0303]

So you removed the fan motor from the housing to inspect it? Maybe you disturbed something inside when you were looking around and that is now causing the new issue.

 

[racket]

err4 can also be an igniter issue. Normally it would be err5 but in some cases I have seen a faulty igniter go err4.

 

[Canadaguy1]

Thanks for you responses. I checked all the wiring and reconnected the vacuum hose. I may have disturbed something under the top or around the vacuum switch but i'm not seeing anything. With regard to the error message I'm just getting ERR with no number. Any idea what could cause such a message?

 

[ps0303]

ERR tells me you have a bad Thermistor.

 

[racket]

Err can also be caused by improper voltage feeding the board. You can check the thermistor by removing its connection from the control board licking your finger, and hold it on the 2 pins (No I am not kidding) turn on the heater It should say "LO" if it does, then replace the thermistor. I still have an issue with the fact that you have no voltage going to the igniter yet the gas valve will get 24vac. It tells me that your problem there is likely in the ignition module.