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Billy
Billy, Technician
Category: Pool and Spa
Satisfied Customers: 22429
Experience:  Licensed in Hydronics and Boilers
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I have a minimax 400 critters ate all the wires and melted

Customer Question

I have a minimax 400 critters ate all the wires and melted them burned out the controller so we re wired and replaced the controller. Now the service light is on and on the back of the board the PV light is off. all other lights are on except heat. suspect the gas valve also got fried.
Submitted: 1 year ago.
Category: Pool and Spa
Expert:  Billy replied 1 year ago.

hello, can you tell if the pressure/flow switch is making contact? Does the pump start?

Use reply

Customer: replied 1 year ago.
If you jump the leads to the pressure switch it remains the same. Pump runs fine. Need to bring a fluke home tomorrow.
Expert:  Billy replied 1 year ago.

understood. once you have the meter, check signal from board to gas valve.

Customer: replied 1 year ago.
Which leads and what voltage should we have? There are three leads plus a ground.
Expert:  Billy replied 1 year ago.

do you have the plus, power max, NT etc?

Customer: replied 1 year ago.
See photo
Expert:  Billy replied 1 year ago.

thank you...do you see MV. PV and MV/PV?

Customer: replied 1 year ago.
see photo
Expert:  Billy replied 1 year ago.

what happens is PV on gas valve gets power ...at the same time ignitor starts...once pilot is lit...then MV gets power.

We want to see if pv on the valve gets power....if not we go to the ignition control box and check for pv power leaving that control

Customer: replied 1 year ago.
I am not getting a spark so I don't expect that any power is being sent to the valve until we at least have a spark. Does that make sence?
Expert:  Billy replied 1 year ago.

that is correct...spark and pv get power at sametime.....now on the ignition control is a 24v terminal. this terminal must get 24v to be able to send pv and spark power...this comes from an air switch that must make contact.

see page 33 HERE

And follow the 24v wire from ign control back to air switch and see if air switch is closing

Customer: replied 1 year ago.
Ok got it let's get the meter and re convene tomorrow.
Expert:  Billy replied 1 year ago.

terrific...just keep this on your end until ready or it will force a response from me. Disregard computer generated prompts

Customer: replied 1 year ago.
Ok sorry very sick dog.
No air switch this is for vented unit ours is open. This lead goes directly to the th-w terminal on the ignition module. It went to the 24v on the old ignition module but the conversion table explains this. There is no voltage on this line at this time.
Expert:  Billy replied 1 year ago.

Ok, so whether on TH or 24v..the end result is there is no 24v on this wire correct?

Customer: replied 1 year ago.
Correct when calling for heat or when not got nothing.
Expert:  Billy replied 1 year ago.

ok, now it is just a matter of back tracking to find where 24v ends.

OR...start at the beginning and trace 24v from thermostat..through limits. The end result is nothing happens until 24v is on that wire to TH-w

Customer: replied 1 year ago.
Ok getting dark I will follow the 24 v tomorrow. Bare with me I have to go back to the vet as well.
Expert:  Billy replied 1 year ago.

was at the vet today myself....just keep this on your end until ready

Customer: replied 1 year ago.
Pink is where I find 24V P11 wire 3 Is mis marked there in no voltage there.
Expert:  Billy replied 1 year ago.

using a wire as a jumper...jump from a known 24v to the THw briefly and tell me if spark starts

Customer: replied 1 year ago.
I already have 24V on the TH-W
Expert:  Billy replied 1 year ago.

Ok, thats great..last time we didnt have it.

I assume it is not working even with 24v on TH?

Customer: replied 1 year ago.
definetly have the 24 there .
Maybe the five buck meter I have at home VS the thousand buck fluke from work.
Expert:  Billy replied 1 year ago.

before we go further..move that wire to 24v terminal and tell me result

Customer: replied 1 year ago.
Same no changes
Expert:  Billy replied 1 year ago.

wow...ok, is the 24v com secure and attached? Once 24v hits that control it starts spark an PV right away

Customer: replied 1 year ago.
Spark led no spark
Expert:  Billy replied 1 year ago.

pull the spark cable and then use a wire with one end to cabinet metal and the other end 1/8 " from spark terminal..tell me if any spark jumps the gap

Customer: replied 1 year ago.
No spark
Expert:  Billy replied 1 year ago.

and you have NO vent damper I assume?

Customer: replied 1 year ago.
No damper
Expert:  Billy replied 1 year ago.

And when THw gets 24v does PV?

Customer: replied 1 year ago.
No J11 #3 PV has no voltage
Customer: replied 1 year ago.
Found this I think we have flash flash on the spark LED but I need to maybe shoot a video to be sure.