Help me diagnose my heater problem

[Theo]

I have a 3 year old Jandy (Laars) LX NG Heater. It was installed along with the rest of the pool by Pioneer Pools back in 2007. I've owned the house for 3 weeks and I'm not 100% sure how well the pool or equipment have been maintained based on the general upkeep of the rest of the house.

The heater had worked fine up until 3 days ago when there was a faint odor of unburned NG and the message SERVICE AGS. I've cut power to the heater and tried to restart it. It will start, then after 30 seconds the display will briefly flash "HEATING". At this point there is hot exhaust exiting the heater. 30 seconds later the heat stops and I get the SERVICE AGS indicator.

I found a copy of the Jandy LX trouble shooting cart thanks to TFP and I'm having a hard time interpreting exactly what I should be looking at.

[attachment=0:cj020luy]Jandy Trouble Shoot Snipe.jpg[/attachment:cj020luy]

"AGS indicates a problem
with oscillating filter pump
pressure or flame rectification.
Is the system circulating properly?"

Is this in reference to my Hayward pool pump and sand filter or is there a filter on the heater I should be looking at?

- If it's in reference to the Hayward Pump I have cleaned the filer and there doesn't seem to be any osculation coming from the pump. If I grab the flexible pipe that runs from the pump to the filter there are no vibrations. However if I grab the return pipe from the filter to the heater it does vibrate. You can certainly feel it and you can more or less see it vibrate. Not sure if this is normal.

- I have backwashed the filter and the water in the sight glass and exiting the hose is clean and clear. The pressure gauge dropped from 26PSI to 22PSI. The vibration on the return pipe remains.

The problem with the heater persists.

If that vibration from the return is normal I can move on to the next step. IS that vibration normal???

Error Message - AGS
Is flame present?

Yes - I can see it and the heater is temporarily firing up.

Next Step

Error Message - AGS
Remove Black wire in terminal
FS from the Ignition Control.
Do in Micro-amp test.
Is 5 Micro-amps present?

I'm not sure I'm capable of doing a micro amp test. Can I do this with a regular multimeter or do I need a specialized tool?

Check Flame proving Rod
for damage, poor alignment
with burners, bad connection
to Black wire.

I'll check this in the AM.

 

[4JawChuck]

Many NG heater issues can be traced to a defective pressure switch, I know mine is set at 20psi and can trip at pressures as low as 18psi but my heater is much older than yours. You can remove the terminals from the switch since they are normally open to see if the switch is tripping the safety. Its easy to test and identifying the switch is simple as it will be the only electrical component with a plumbing connection so it sees pump pressure. Your unit may also have a flow sensing switch (most newer models have this feature) to ensure the unit has moving water before heating.

Check your units maintenance manual for components and locations, usually available on the mfg website.

 

[Theo]

I'll check the pressure switch this afternoon. Thanks!

 

[4JawChuck]

The pressure switch on my heater looks like an automobile oil pressure sending unit but with screw terminals instead of slip-ons. Flow switches vary depending on mfg and design so I can't help you there.

Let us know how it works out, nothing better than knowing what the actual problems was...may help someone else in the future.

 

[danbutter]

Many NG heater issues can be traced to a defective pressure switch

Yep I have a buddy who had the same issue with his...he just replaced his pressure switch too.

 

[Theo]

Turned out to be spider webs in the venturi.

 

[Theo]

I had another "SERVICE AGS" error last night. I was quite concerned because I thought it couldn't be spider webs again (I had them cleaned out 4 days ago!) so I instantly thought something else had faulted.

I'm glad I started with the most obvious solution first because 2 of the 5 ports were totally blocked by spider nests and another one was partially blocked! I cleaned them out with a pipe cleaner and the heater fired right up! It's a good thing too because the water was @ 71 deg and we're having out final pool party of the season today. I had promised a warm pool!

My other problem is a group of snakes that like to hang out near the pool equipment. I'm not especially fond of snakes but I'm trying to tolerate these guys because my kids like them. As long as they don't sneak up on me while I'm near the equipment I thought we'd all get along. This happy co-existence will change if the snakes don't get off their asses and start eating these spiders!

 

[4JawChuck]

My problem is with mice, they like to get up inside my unit and build a nest in the top of the vent stack...easy enough to make a screen to keep them out. Spiders seem like an impossible foe to thwart though!