MiniMax 400 Not Turning Gas On

[ssmith579]

My MiniMax 400 pool heater is not turning the gas on. The pilot light is on. The thermostat works. It's either the gas control valve or the controller. Anyone know how to figure out which one it is? There are three wire to the gas valve, red, white and blue. I assume one of these should control turning on the gas. Looking for any troubleshooting tips.

Thanks,
Steve

 

[Guest]

The MiniMax is notorious for bad boards. Pentair does not make this heater any longer, in part to the board issue.

Have you checked the flow switch? Are the burners clean?

 

[ssmith579]

I think I've narrowed this down to the pressure switch. Ran out of time yesterday to try bypassing it. Is there a schematic available for the controller board? It's pretty simple and would be easy to design a new one.

 

[Guest]

Try this: http://www.pentairpool.com/pool-pro/man ... n.php?s=28

Might be able to find it there.

 

[ssmith579]

OK, it's not the pressure switch. I'm pretty sure it's either the gas control valve or the ignition module. Does anyone know what voltages should be coming out of the ignition module? I'd like to know what I should be measuring on the MV, MV/PV and PV terminals on the module.

 

[PoolGuyNJ]

If I remember right, the voltage generator is a probe sticking in the pilot. When heated, the probe should produce at least 300 millivolts DC to fire but only 225 to keep the pilot lit. I am not 100% on the numbers for this heater. specifically.

Scott

 

[ssmith579]

I have narrowed this down to the S8600 control module for the gas valve. I found a troubleshooting guide that told me the voltages required to operate the valve. I wasn't getting 24V on the MV terminal. I jumpered 24V to this and the heater came on. I'm getting a new control module so hopefully this will take care of the problem.

 

[PoolGuyNJ]

A 24V signal implies the heater is electronic and a hot surface igniter like a car's cigarette lighter element. If you have a pilot light, it is not.

All signals will be in the millivolt range. I think you will need to either further qualify or re-review the document.

Scott

 

[ssmith579]

It's a VR8304 gas valve and S8600 ignition module. I found the following in a trouble shooting guide. It's not a millivolt system. It's over 15 years old also. The pilot is only on when it's energized.

How to check Gas Control Valve - Honeywell VR8304
The VR8304 gas control provides ON-OFF manual control of the gas flow. In the OFF position, the pilot
and main burner gas flow is prevented. In the ON position, pilot and main burner gas flow is under control of the
Honeywell 8600M electronic control module.
If main burner and or pilot will not light:
1. Check the gas control knob is in the ON position.
2. Verify the presence of a spark at the electrode assembly. You may need to recycle the heater by turning the
ON/OFF switch to OFF, waiting one minute and turning the switch back to ON. Also check the wiring harness
connections are clean and tight.
3. Adjust the thermostat to its highest setting to demand heat.
4. Using a multimeter check for 24 volts at the gas control:
a. If pilot lights, measure across the MV/PV and MV terminals (blue & white wires). If multimeter does
not register 24 volts, replace the ignition control module. If the multimeter registers 24 volts replace the gas control
valve.
b. If pilot DOES NOT light, measure across the MV/PV and PV terminals (brown and white). If
multimeter does not register 24 volts, replace the ignition control module. If the multimeter registers 24 volts
replace the gas control valve.