Jandy Lx400 Heater Problems - Won't Light

[austinmf]

We have a Jandy LX400 that has never worked correctly....always have to use the control box as the PDA will not touch it...

[dyslexic_jim]

I'm not harping on you, but always remember, easy does it and simple kicks butt.

Any heater that lights, and then shuts off, should first be checked for a faulty or dirty flame detector. If you heater ran great when it was new, a gas flow issue is not likely (not impossible - but not likely).

My Jandy did the same thing. Fortunately, the furnace is my X wife's house was doing the same. Cost her 56 bucks to have the "flame detector" cleaned....so, I followed suit. Found a fractured wire leading to my flame detector on my pool heater, corrected it - runs great ever since.

I too was considering gas flow, water flow, dirty filters (even though my pump is way over powered), but when I heard her heater in her home doing the same thing, and then found out the repair - I knew where to look on my Jandy.

I called the pool heater guy out, he charged me 105 bucks to tell me I was right - and then I cut him off from the repair - I just stripped the wire down to clean wire and soldered it back on....

My pool is 88 degrees right now - and I'm going swimming with a few beers....LOL....

P.S. - my Jandy is 6 years old and has had this problem since it was new.....at first it was just every once in a while...and it got worse and worse until it took an acto of God to get it to stay lit.......now - first time - every time.

Good Luck.

They say "Blue Sky's" in skydiving - so let us just say, "Blue Water!!!!"

[Coldtub]

I'm not harping on you, but always remember, easy does it and simple kicks butt.

Any heater that lights, and then shuts off, should first be checked for a faulty or dirty flame detector. If you heater ran great when it was new, a gas flow issue is not likely (not impossible - but not likely).

My Jandy did the same thing. Fortunately, the furnace is my X wife's house was doing the same. Cost her 56 bucks to have the "flame detector" cleaned....so, I followed suit. Found a fractured wire leading to my flame detector on my pool heater, corrected it - runs great ever since.

I too was considering gas flow, water flow, dirty filters (even though my pump is way over powered), but when I heard her heater in her home doing the same thing, and then found out the repair - I knew where to look on my Jandy.

I called the pool heater guy out, he charged me 105 bucks to tell me I was right - and then I cut him off from the repair - I just stripped the wire down to clean wire and soldered it back on....

My pool is 88 degrees right now - and I'm going swimming with a few beers....LOL....

P.S. - my Jandy is 6 years old and has had this problem since it was new.....at first it was just every once in a while...and it got worse and worse until it took an acto of God to get it to stay lit.......now - first time - every time.

Good Luck.

They say "Blue Sky's" in skydiving - so let us just say, "Blue Water!!!!"

[Coldtub]

Very interesting that we all have similiar issues at one time or another. Now mine is lighting fine, stays lit for a while, and then shuts off before the water gets warm. What do you suppose is going on here and what is the fix?

[Pool Clown]

Perhaps the flame proving rod has gotten just sooted enough to make it shut off intermittently. Check the rod for soot build up, and a good wire from it to the board.

[Coldtub]

Perhaps the flame proving rod has gotten just sooted enough to make it shut off intermittently. Check the rod for soot build up, and a good wire from it to the board.

[Coldtub]

ok so I pulled out the flame sensor rod and used a little sand paper to clean off. Also checked the wire and the connections and they appear to be fine. Fired it up again and still have the same problem. the heater stays on for about 20 minutes or so and then shuts off well below desired temp.

[Pool Clown]

OK, try this... There is a jet (gas) just under the flame proving rod. Remove that jet (it's the brass fitting screwed into the black header), and check it for a spider web or some other blockage.

In this picture, You can just barely see the flame proving wire (black) where it goes into the fire box. It's the 4th jet from the right that you want to remove and inspect.

[Coldtub]

Thank you - I really appreciate your advice. I just removed the brass fitting and made sure it was clear and it was. I just started the heater and again it shut off after about 15 minutes or so.

[Pool Clown]

Is it by chance heating to about a certain temp every time (not the set point) it begins to have the shut off problem?

[Coldtub]

The temp controls are set all the way to the hottest point, so yes, the heater shuts off after about 15 to 20 minutes. If I try to restart I can not get it to go again for a while.

[bubbadoom]

Sticking, or intermittent voltage to gas valve?

When the air is cool, does it run for more than a min or two(the fan)?

Between 15-30 sec after the fan starts, can you hear the gas valve click open?

The fan runs for as long as I have the heater "on". The system says "Heating" but the vent seems to be blowing gas because I can smell it from the vent.

I finally started getting an error on it: AGS

When it works, I can tell it starts because I can hear the the gas light and the exhaust sounds different.

[bubbadoom]

Sticking, or intermittent voltage to gas valve?

When the air is cool, does it run for more than a min or two(the fan)?

Between 15-30 sec after the fan starts, can you hear the gas valve click open?

The fan runs for as long as I have the heater "on". The system says "Heating" but the vent seems to be blowing gas because I can smell it from the vent.

I finally started getting an error on it: AGS

When it works, I can tell it starts because I can hear the the gas light and the exhaust sounds different.

I did get my heater repaired. The problem was 2 fold - the controller box below the lcd panel (not the lcd panel part) had a chip that was dying and the connector board in the middle of the heater had some water damage on it, so if the humidity was just right, something would short so it would think it was on when it was not. I think the main problem was the connector board in the middle which everything plugs into. Now I am ready to enjoy the summer!

[Pellis87]

Can someone help me with my Jandy LT400?

I have a low nox LT heater that was installed in 2006, it's wired for 230 volts.

I keep getting code AGS, every time I try to use the heater.

First I noticed on the Fenwal control that L1 and IGN 120 were shorted and the board was burnt. So I replaced it, but I still have the same code.

A pool builder suggested the HSI should be replaced, so I did that and found the old HSI was broken in several pieces, but I still have the same AGS code after replacing the HSI.

I have tried to trouble shoot the heater from the manual, but found a couple of things that make no sense:

The supply voltage checked out okay, but when checking voltage across transformer points, I found the voltage according to Table 13 of the owner’s manual to be backwards on my heater.

Voltage between points D and E was 246 volts, and points F and G showed 0 volts.

Also when testing the HSI points H and I, it reads only 36 Volts, the manual states it should be 98v to 126 volts.

I was thinking the power distribution board was bad, but after removing it for a closer look, everything looked fine on it.

Also, I know it’s crazy to do, but I lit the heater with an open flame and the heater stayed on till I turned it off several hours later.

So, this leads me to believe the HSI isn't getting enough voltage, so it doesn't get hot enough to light the heater.

Can anyone offer any advice why the voltages are wrong?

[Pool Clown]

Low NOx

Non Lo NOx

Figure this is better than trying to walk you through all of it.

[Pellis87]

Thank you Pool Clown for such a quick reply and the flow charts. I had already found the low NOx chart from one of your earlier post, but I couldn't understand why the HSI isn't getting the right voltage. Can you help me understand how the IGN 240, IGN 120 and L1 relate to the HSI?

[Pool Clown]

You should start at the beginning, and check the X-former voltage with this flow chart. And keep going till you find the problem.

"Voltage between points D and E was 246 volts, and points F and G showed 0 volts."

Not sure where those test points are. This way, it's easier to follow colors...

[putyouallin]

Let me start off by saying... I'm way out of my league on this one. I thought I was pretty mechanically inclined and pretty logical when it comes to anything but women. I just bought my first home with an amazing pool/spa and it has multiple issues. I just spent $800 (can't afford to spend much more) on draining the pool, chlorine wash, and repairing the filter. It has fresh water and gets great pressure. I was told that the problems with the pop-ups and heater were pressure related. He told me that once we fixed the filter that the other devices would work. I feel like an idiot for believing that. I'm not going to worry about the pop-ups right now, but getting the heater working is essential. PLEASE HELP!!!

I will try to tell you everything you may need to know to help me figure out the best approach at getting this resolved on a budget. The heater has worked in the past, but I am not sure how long it has been since it has been used last. This is strange to me, but I do not know what kind of problems this may cause or has caused already. IT IS NOT MOUNTED ON CONCRETE BLOCKS OR EVEN A SLAB. I know that it had to pass an inspection from Southwest Gas (Arizona), but do they know the specific requirements the heater manufacturer requires? Do they have to use common sense? I may just be an idiot and maybe this step is NOT necessary. It looks really dirty on the inside of the unit when I took off the panel. I have read this post (THANK YOU VERY MUCH TO EVERYONE WHO HAS CONTRIBUTED)and decide to call the gas company to come out to make sure I'm getting the right amount of pressure. He said the pressure is great. He measured it right at the input of the unit and said it measured 8.1 (whatever that means). I also asked him about the meter. He said that the meter was HUGE and that could easily be ruled out. He seemed very experienced and I feel pretty certain that we can rule out the heater not getting the right amount of gas to it, but what does it do with it once it gets there?

When i try to fire it up I can smell the gas and it does try a few times before I get the AGS error message. I found a receipt for a part the previous owner had purchased and it was the gas manifold. I am a bit nervous to call someone from Jandy from reading all of these horror stories. I can not afford to drop a ton of cash on it, but I really would like this to get fixed. Does anyone have ANY advice? Should I call one of my local service specialist? I can not afford to waste more than $100 on getting someone out here just to have me buy parts that may or may not fix my problem. Sorry, I just have a hard time trusting some of these service guys. They really can be just glorified salesmen.

PLEASE HELP!!

Brgds,

Mike

[Pool Clown]

Mike, Welcome to the forum.

If you can smell gas, the gas valve is opening (duh) which means everything was satisfied in the heaters safety circuit(s). So that just leaves ignition. My guess is the igniter(HSI) is either not getting voltage(Fenwall not closing), or it is cracked, and won't glow or get hot enough for ignition. If you take it out and inspect it, it will be evident, kind of a white scale surrounding the crack.

An igniter will probably be over 100 dollars from the pool guy. Who knows what kind of a deal you can get on line.

A service call i'm sure will be over a hundred too.

Sorry, blew your budget...

[Bugman1400]

Mike, Welcome to the forum.

If you can smell gas, the gas valve is opening (duh) which means everything was satisfied in the heaters safety circuit(s). So that just leaves ignition. My guess is the igniter(HSI) is either not getting voltage(Fenwall not closing), or it is cracked, and won't glow or get hot enough for ignition. If you take it out and inspect it, it will be evident, kind of a white scale surrounding the crack.

An igniter will probably be over 100 dollars from the pool guy. Who knows what kind of a deal you can get on line.

A service call i'm sure will be over a hundred too.

Sorry, blew your budget...

"

If you are cheap like me, you can get the ignitors (glo bars) from a commercial washer/dryer place for about $10. Try Summit Parts and do a search for "flat glo bar".

I have also had my battle with putting in an LT400 gas heater myself and would like to add my two cents. I bought my heater used. After reading this fantastic forum, I was able to figure out that a few passes of sandpaper over the flame sensor to clean off the soot fixed half my problems. The other half of my problems was not having a regulator at the heater. Initially, I thought there was insufficient amount of gas getting to the heater since it was opposite of the gas meter side of the house. Since I had a valve and a union at the heater, I just disconnected the heater at the union and vented the gas to the air and it sounded like it had plenty of pressure and volume to me. So, then I figured that the gas was regulated enough at the gas meter. Not so! In my case, the pressure was too high at the heater's gas valve. Apparently, the heater's gas valve has a way of detecting if the gas pressure is higher than it can handle and will prevent any gas from entering the valve body. I bought another gas valve and an electronic manometer trying to figure this damn thing out. Once I added a 3/4" regulator at the heater, it started up first time and has been running ever since.

[bavarian]

Pool Clown--or anyone else, please help!

I have a three year old Jandy LX 250-L.

In the beginning I had the same ACS problems with the heater turning on and trying 3 times to stay lit, and then turning off. Long story short I had everything done including a larger gas meter, bigger main gas line etc. It was finally fixed, and I now also know to clean out spider webs in the gas jets when opening the pool in spring.

This year, there is something else going on: the heater does not even try to light (gas and electric power is on and fine). Instead, after several minutes in the "on" position, I get error message: SERVICE---EXT SW 1 (extra switch #1)

From the manual it sounds like one of three things: first a tripped exhaust temp limit switch. Is there a reset button that is accessible so I can try it? I have a feeling it is way back behind the thermostat and I'd rather not get that deeply involved as I might screw something up. (The other two possible causes require special service)

Any thoughts would be much appreciated.

[Pool Clown]

EXT. SW. 1 - Fusible Link or exhaust temp. limit switch open.

Too much heat in the cabinet(fusible link)

or flue(exhaust temp. limit switch).

If fusible link, replace and check for sooted exchanger, low gas pressure (causes sooting), down draft condition, and/or water flow problem(dirty filter, clogged pump impeller, full skimmer or pump strainer basket(s)).

If exhaust temp limit switch, check for blockage, or partial blockage of vent (sooting).

[bavarian]

EXT. SW. 1 - Fusible Link or exhaust temp. limit switch open.

Too much heat in the cabinet(fusible link)

or flue(exhaust temp. limit switch).

If fusible link, replace and check for sooted exchanger, low gas pressure (causes sooting), down draft condition, and/or water flow problem(dirty filter, clogged pump impeller, full skimmer or pump strainer basket(s)).

If exhaust temp limit switch, check for blockage, or partial blockage of vent (sooting).

Thanks so much--I will look into it more

[kholmes]

You should start at the beginning, and check the X-former voltage with this flow chart. And keep going till you find the problem.

"Voltage between points D and E was 246 volts, and points F and G showed 0 volts."

Not sure where those test points are. This way, it's easier to follow colors...

Pool Clown-

The test points that this post is referring to are from the LX Low NOx manual page 39:

Table 13. Voltage Supplied To Transformer

MEASURE EXPECTED EXPECTED

BETWEEN VOLTAGE WITH VOLTAGE WITH

THESE 230V SUPPLY 115V SUPPLY

POINTS

D and E 0 98 - 126 Volts

D and F 98 - 126 Volts 98 - 126 Volts

D and G 98 - 126 Volts 0

E and F 98 - 126 Volts 0

E and G 98 - 126 Volts 98 - 126 Volts

F and G 196 - 253 Volts 98 - 126 Volts

1. Point D is the location at which the white wire with the black

trace enters the 4 pin connector.

2. Point E is the location at which the white wire with the red trace

enters the 4 pin connector.

3. Point F is the location at which the red wire enters the 4 pin

connector.

4. Point G is the location at which the black wire enters the 4 pin

connector.

I had the exact same issue as this. 240V at points D and G. 0V at F and G. This hapend after my HSI went out. while testing the HSI, I disconnected the wires to get a resistance reading. The plug shorted on the side of the heater box. I replaced the HSI and now no fan etc. I found that the Ignition control (fenwal) was fried so i replaced it. I figured it was a result form my stupidity at not cutting power before disconnecting wires. Now i get no fan and a blink on the led on the Fenwal, indicating an air flow fault. Oh and still 240V at points D and G. 0V at F and G.

I followed the flow chart you posted earlier and was not getting voltage at step three- check safety loop- when i tested the fifth wire. Flow chart says check connections and/or change thermostat. My concern here is that in the manual it says to check voltage supplied to the transformer BEFORE checking output from transformer. What i'm wondering is if I have fried my power supply circuit board and or my controller, or is it just the thermostat. I would hate to have to replace every component in the heater if i don't have to.

Any advice would be very helpfuland greatly appreciated. I promised the wife a warm pool/spa by June 11 (her birthday) and i'm hoping to keep my promise.

[Vinny89]

My Jand LX400 does the same thing since I had my pool installed 6 years ago. The problem is spiders lay their nests inside of the brass jets shown in the picture shown in this forum. I got an airbrush cleaning kit from Harbor Freight tools for $1.99 and cleaned each jet and it fixed the problem. There was lots of spider eggss that I pulled out from many of the jets.