Pentair Mastertemp 200 wont ignite.

[Tlittzen]

I'm currently servicing a heater for a customer that won't ignite. It will run through 1 cycle of trying to ignite, blower kicks on, gas valve opens, I can smell the gas but no ignition. The service heater LED comes on and then locks out the controls. The AGS light on the back of the control board lights up also.

I started with replacing the hi limit and AGS Sensor with no luck, then tried the Thermistor, pressure switch and ignitor. Also tried bypassing the AGS with the same symptoms. The fenwall isn't blinking or showing any codes. Starting to get worried it needs a new board. Any ideas?

 

[Poolbreh]

You can inspect the board, clean off any dead insects or creatures that may have gotten in there. Check all the wiring to ags clean connectors. Check continuity or ohms of ags switch it should be closed. If all checks out it’s probably a bad board.

 

[1poolman1]

I'm currently servicing a heater for a customer that won't ignite. It will run through 1 cycle of trying to ignite, blower kicks on, gas valve opens, I can smell the gas but no ignition. The service heater LED comes on and then locks out the controls. The AGS light on the back of the control board lights up also.

I started with replacing the hi limit and AGS Sensor with no luck, then tried the Thermistor, pressure switch and ignitor. Also tried bypassing the AGS with the same symptoms. The fenwall isn't blinking or showing any codes. Starting to get worried it needs a new board. Any ideas?

AGS is not a sensor in the truest sense but just another hi-limit that reacts to overheat. Generally, it trips if the internal bypass or thermal regulator are bad, bypassing too much water and what water does go through the heat exchanger is coming out too hot. If you are going to replace one, you should replace both the bypass and thermal regulator at the same time, they both seem to suffer the same amount of damage at the same time.
Have you followed the troubleshooting process found in the manual?

 

[Tlittzen]

AGS is not a sensor in the truest sense but just another hi-limit that reacts to overheat. Generally, it trips if the internal bypass or thermal regulator are bad, bypassing too much water and what water does go through the heat exchanger is coming out too hot. If you are going to replace one, you should replace both the bypass and thermal regulator at the same time, they both seem to suffer the same amount of damage at the same time.
Have you followed the troubleshooting process found in the manual?

I have, but have not replaced the internal bypass or thermal regulator just yet. The heater does not kick on at all, just goes through one cycle and locks out.

Will a bad thermal regulator and bypass trip the AGS even with no heat? I was going to try those next but was unsure if it was the board. Even with the AGS switch jumped and bypassed it still won't ignite and gives me the AGS LED.