If you have access to a manometer, you can check the gas pressure coming out of the regulator.

One thing is if the air was never purged out of the line, it could take a while to fire the heater.

13 psi is tough on the valves, and it wouldnt surprise me if you blew something out of the gas valve. The gas valves really dont like pressure greater than 14" w.c. which is 1/2 psi

When was the last time it actually fired? If the gas line was open, you will have air, but you said you smelled gas. You could have a rusty pilot orifice too. On that heater, if you are getting spark and smell gas, the mechanics of the safety loop circuit are working fine or you would not get a spark. You can loosen the pilot tube from the valve and then turn the heater on until you hear the valve click. Gas should come out of the 1/4" hole. If it does, that portion is ok. Put it back and tighten. Fire it back up and listen for gas down in the pilot area. DO NOT PUT YOUR HEAD THERE AND IF YOU HEAR THE SPARK STOP, MOVE OUT OF THE WAY QUICKLY! If it continues to spark AND you smell gas, you have a further diagnosis to do.

If you have gas at the pilot and spark, you have to have flame unless the spark gap is way out of whack. If you have spark and no gas, it is a plugged burner, bad ignition module or bad valve. Those tests need run. For the valve to be bad, you would need to have flame at the pilot and hear a click at the valve with no ignition. that would still not narrow it down w/o tests.

Let's assume spark and no gas. Put a test lead on the valve ground and the PV terminal on the gray ignition module with the heater on. No voltage (24) there means a bad module. Let's assume, spark, gas and no flame. That would be a pilot issue. Let's assume, spark w/flame and no ignition. You need to confirm where the 24volts stop. It could also be aloose ground. You can put a test lead on the valve ground and then put it to the mv terminal on the gray ignition module. Voltage there (24)indicates the module is good. Put the lead down to the mv terminal on the valve. Voltage there (24)and no main valve operation means your valve is toast.

Thanks so much for the responses. After trying it again it seems to light fine (several days later). Our only thought is that there was still air in the line. We tried several different thigs orignally and two days in a row but maybe it just took some time for the air to get the air out of the line. Whatever the case may be it is working fine and we are thrilled.

Thanks again!
Vicki

When you break a gas line it takes a very long time to purge it out through the little tiny pilot orifice. Typically in the field we will break apart a union to speed up the process.

Glad to hear that it is running.

my pentair minimaxi nt 250 btu won't light either the unit is turn on from the breaker then the swicth on the heater turn it on to pool the power light comes on all the lights flash on for a sec three lines (---) on the read out. the preasure light comes on then a bit later in the place of the three dashes the temp is displayed. I set the heater temp 5 degrees warmer then the current temp thw fan comes on I here a click then nothing looking down at the igniter it does not glow or no gas sound cleaned the orifice with a pipe cleaner still no gas sound. Took the line 1 and line 2 leads from the ignition control module and ran them to the 2 igniter wires turn on the power seitch and the igniter glowed just fine so I am not getting power to the igniter and the gas valve im thinking is this a bad igniter mod or I read it could be a bad thermister if you have power preasure thermastat but no heat light help someone please the=is heater has never been used it sat outside for years the burner tubes look brand new please advise