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Laars Lt Heater Question


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Hi everybody ,

I have a laars lt heater that is heating a 15000 gal pool and switchable to a spa

1the heater seems to cyle when trying to heat

2the airflow error light comes on after approx 20min, i turn off, turn back on all is fine until 20 min later. Then repeat the process

3with only one water input& output (i can heat the pool and spa seperatly through a series of manifolds) should i use the pool setting or the spa setting, whats the difference

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the fact it has two thermostats really doesn't make a differance it will just heat to the setting of whichever thermostat setting your on, if its cycling it may be a circ problem like the filter is really dirty and needs to be cleaned ( cartiage ) or backwashed if its a sand or de type, does it knock when trying to heat and if so will it stop as soon as you turn the heat off but keep it circulating, ? usually a flow or thermal governor problem if you have cleaned the filter and it still is persisting you may just have to call a tech out. few other things it could be also.

Michael

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You can try to run the heater(plumbing) in pool, or spa, to see if it runs one way and not the other.

You must determine if it is the heater thats having a problem, or if the heater is just reacting to a problem within the system, as previously stated.

An air flow error is because the airflow switch is opening. Now that could be because the fan is not "blowing" enough air, sometimes they do this when they are going out, but normally will blow at reduced flow all the time, not after 20 min.

Or the switch is bad, just barely. It'll work OK then the switch begins to slowly leak down, and open. OR... And i hate this one, the switch is connected right to the PCB, and it could be interrupting on the board which would mean a new board. It's hard to diagnose those heaters over the internet. Failures with heater components can have a handful of symptoms.

Really need to be on site to properly diagnose/fix 'em.

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AIR FLO SW

(air flow switch)

1. Broken, split, pinched or disconnected fan/switch tubing.

1. Check tubing and replace if necessary.

2. Fan not operating. 2. Correct fault or replace fan.

Refer to qualified service personnel.

3. Fan running slow or premature fan failure.

3. Verify proper wiring for 120VAC or 240VAC. Refer to qualified service personnel.

4. Air flow restricted at intake or discharge.

4. Check for proper clearances around heater and for adequate room ventilation if enclosed. Inspect for blockage or restriction at discharge or flue. Refer to qualified service personnel

http://www.jandy-downloads.com/pdfs/LXandLT_H02140B.pdf

Since you are getting an air flow error indicator, that needs to be investigated and corrected. The heater will shut down when an air flow fault is detected.

The tubing tends to get brittle and crack at the ends, especially if the exhaust is running hot. The tubing does not seal well to the switch and can come loose when it is cracked and brittle.

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He stated that it runs for twenty min before it shuts off. What does the manual say?

AIR FLO SW

(air flow switch)

1. Broken, split, pinched or disconnected fan/switch tubing.

1. Check tubing and replace if necessary.

2. Fan not operating. 2. Correct fault or replace fan.

Refer to qualified service personnel.

3. Fan running slow or premature fan failure.

3. Verify proper wiring for 120VAC or 240VAC. Refer to qualified service personnel.

4. Air flow restricted at intake or discharge.

4. Check for proper clearances around heater and for adequate room ventilation if enclosed. Inspect for blockage or restriction at discharge or flue. Refer to qualified service personnel

http://www.jandy-downloads.com/pdfs/LXandLT_H02140B.pdf

Since you are getting an air flow error indicator, that needs to be investigated and corrected. The heater will shut down when an air flow fault is detected.

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He stated that it runs for twenty min before it shuts off. What does the manual say?

I posted a link to the manual and what it says to check when an air flow error is indicated. What are you asking about? What does it say about what?

I would first check the tubing. It will become cracked and brittle at the ends, and then it won't make a good seal. A weak tubing seal can cause this type of cycling. It the tubing is cracked, brittle and/or discolored at the ends, where it connects to the switch, it usually indicated an excessively hot exhaust, sometimes due poor air flow.

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But it runs for twenty min. Cracked tubing isn't going to wait twenty min, then start leaking. How many times have you seen that?

There might be multiple problems contributing to the air flow error. All of the possible causes should be checked. If there is low air flow, then the exhaust will be too hot and cause tubing failure. A combination of causes can be cause the switch to be on the borderline of being open or closed.

The point i was trying to so delicately make, is that your post sounded as though you hadn't read any other post but the first.

I had read the first two when I wrote my post. You had not yet posted when I first read the problem and started writing my post. You posted while I was writing my post. I only saw your post after I posted my post.

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But it runs for twenty min. Cracked tubing isn't going to wait twenty min, then start leaking. How many times have you seen that?

There might be multiple problems contributing to the air flow error. All of the possible causes should be checked. If there is low air flow, then the exhaust will be too hot and cause tubing failure. Yes, but have you ever witnessed this? or is it just speculation? Twenty min cycles? A combination of causes can be cause the switch to be on the borderline of being open or closed.

The point i was trying to so delicately make, is that your post sounded as though you hadn't read any other post but the first.

I had read the first two when I wrote my post. You had not yet posted when I first read the problem and started writing my post. You posted while I was writing my post. I only saw your post after I posted my post.

I suppose theoretically it could happen. I've just not seen that type of cycling when there are cracked hoses. It will usually not run 20 sec. let alone 20 min. before it cycles, consistently. Have you?

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I suppose theoretically it could happen. I've just not seen that type of cycling when there are cracked hoses. It will usually not run 20 sec. let alone 20 min. before it cycles, consistently. Have you?

Anything that is going to cause an airflow error should usually happen immediately and prevent the heater from starting. The twenty minute interval before faulting is unusual.

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Anything that is going to cause an airflow error should usually happen immediately and prevent the heater from starting. The twenty minute interval before faulting is unusual.

Exactly, then why put the cracked hose scenario out there, when it's likely not the problem?

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Cracked or loose hoses are one of the things that should be checked when there is an airflow error. I think that the hoses are a definite possibility. Even if the hoses are not causing the fault indicator, the loss of airflow will cause excessive exhaust temperatures, which can damage the hoses.

The manual lists tubing as the first item on the checklist. That would indicate that the manufacturer thinks that it is worth checking when an airflow fault occurs.

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Never-mind... you missed my point.

I guess what i should have asked you is, can you offer any insight to his problem, or info, that the poster wouldn’t, or couldn't already find on the internet themselves? Any personal experience? something you experienced out in the field? Not found on the internet, and cut and paste into the thread?

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I guess what i should have asked you is, can you offer any insight to his problem, or info, that the poster wouldn’t, or couldn't already find on the internet themselves? Any personal experience? something you experienced out in the field? Not found on the internet, and cut and paste into the thread?

My personal experience out in the field is that sometimes the hoses can become damaged and leak. I have seen it happen. No one else had mentioned it. I didn't just get it from the internet. It is also what Jandy recommends to check.

Sometimes the best thing you can do is direct people to the right resources. There is nothing wrong with pointing out what the manual says. [edit]The original poster[end edit] did not include enough information to indicate any probable or likely cause.

It's hard to diagnose those heaters over the internet. Failures with heater components can have a handful of symptoms.

Really need to be on site to properly diagnose/fix 'em.

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I guess what i should have asked you is, can you offer any insight to his problem, or info, that the poster wouldn’t, or couldn't already find on the internet themselves? Any personal experience? something you experienced out in the field? Not found on the internet, and cut and paste into the thread?

My personal experience out in the field is that sometimes the hoses can become damaged and leak. I have seen it happen. No one else had mentioned it. I didn't just get it from the internet. It is also what Jandy recommends to check.

Sometimes the best thing you can do is direct people to the right resources. There is nothing wrong with pointing out what the manual says. This post did not include enough information to indicate any probable or likely cause.

It's hard to diagnose those heaters over the internet. Failures with heater components can have a handful of symptoms.

Really need to be on site to properly diagnose/fix 'em.

What is it with you and the hoses? There are other things that are probably the cause, yet you focus on the hoses.

I can tell you from experience that of all the cracked hoses i've seen, none of them held for 20 min then let go.

Theres an idea, LET IT GO!

Curious, i wonder why you didn't quote my WHOLE post? just the part that backed up what you are saying. I gave several ideas as to what it may be and OF COURSE there is really no way to diagnose this heater over the internet. And anyone who does conclusively, is really only guessing.

Thats Ok, I'll just start ignoring your posts too, and come in behind you and say again what you just said. As you have done in the past.

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Thats Ok, I'll just start ignoring your posts too, and come in behind you and say again what you just said. As you have done in the past.

I did not ignore your post. As I said earlier, I hadn't seen your post until after I posted. And, I didn't say what you did. I posted what the manual said about what to check. The only thing that was in the manual checklist that you had said was about the fan not operating properly.

Also, when I said, "This post did not include enough information to indicate any probable or likely cause", It looked like I was referring to your post, I meant the original poster. I quoted part of your post to support that. I did not mean to imply that your post was not helpful. I should have written more carefully.

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Thats Ok, I'll just start ignoring your posts too, and come in behind you and say again what you just said. As you have done in the past.

I did not ignore your post. As I said earlier, I hadn't seen your post until after I posted. And, I didn't say what you did. I posted what the manual said about what to check. The only thing that was in the manual checklist that you had said was about the fan not operating properly.

Also, when I said, "This post did not include enough information to indicate any probable or likely cause", It looked like I was referring to your post, I meant the original poster. I quoted part of your post to support that. I did not mean to imply that your post was not helpful. I should have written more carefully.

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