Sta Rite Pool Heater

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C

CanadaDave

0
Jul 28, 2014
33
Windsor
Hi, everyone.

Last year, I moved into a home with a pre-existing concrete pool and spa (both connected to the main system, separated with Jandy valves). Among its equipment is a Sta Rite Max E Therm 400 heater, which is the problem child today.

The heater runs correctly when the system is set to filter only the spa. When the system is only running the spa, the pressure is much higher - approximately 30-35 PSI - because it only has one output for water to flow into the system, as opposed to 4 for the main pool. It typically runs about 20-22 PSI for the main pool.

When I have it set for the pool, it will run correctly for a seemingly random period of time.. sometimes an hour, sometimes 3 hours, and then it will make a fairly terrible noise as shown in the video below, do that noise for around 20-30 seconds, and fail with a "service heater" light. I've replaced several things on the heater because they were easily accessible and old - thermistor, water pressure switch, and thermostat/spring (whatever the term is - looks like a small car thermostat).

In fairness, it's possible that the spa setting would eventually fail as well. I've been in the spa for a couple of hours at times and never encountered it, but I've never tried running it for a full day or anything.

When it fails, it does appear to do a proper shutdown (the "vent" sound continues for a little bit, presumably to cool the heater down), and not some quick "panic" shutdown.

Here's the link to Youtube I managed to capture (sorry for the poor videography):

Here's a video of the problem actually happening.

Please don't pay attention to the pressure display on the pump during the video, as I was quickly trying to see if I could make the heater *not* fail by switching the system to spa very quickly, raising the PSI. While that noise was going on, the heater seemed to be physically vibrating/banging - I could feel it in the gas line and the heater shell, in addition to (obviously) hearing it.

Edit: Once "Service Heater" comes on (approx 45 seconds into video), the noise stops.

I'd love any thoughts people have on how to fix this. I'm still quite a novice with pools having never owned one before.

Thank you!
 
Sounds to me like a one of two things. Either a water flow issue and the little bit of water coming in is boiling in the heat exchanger and making the rattling noise. Or, the bypass is broken. If you are sure water flow is good, to test I usually put my hand by the closest return to the pump and if I can hold my hand over it without the water pushing it away, clean the filter.

To check the bypass, remove the thermal regulator and feel up towards the top. If you can't pull the regulator out because something seems to be preventing it, the bypass has broken and hanging up on it. If it comes out OK no problem, feel up inside towards the top of the opening and you should feel a circle like button. That's the bypass. If it feels solid, it should be good.

One thing, I had a unit fool me a while back. What was causing the issue was about a year ago the owner has the spa resurfaced and they didn't bypass the heater. A bunch of crud starting clogging the heat exchanger. Once it clogged one of the tubes pretty good, clunking sounds started. I was able to flush a good portion of it our with a pretty strong water stream from a hose.
 
ps0303 said:
Sounds to me like a one of two things. Either a water flow issue and the little bit of water coming in is boiling in the heat exchanger and making the rattling noise. Or, the bypass is broken. If you are sure water flow is good, to test I usually put my hand by the closest return to the pump and if I can hold my hand over it without the water pushing it away, clean the filter.

To check the bypass, remove the thermal regulator and feel up towards the top. If you can't pull the regulator out because something seems to be preventing it, the bypass has broken and hanging up on it. If it comes out OK no problem, feel up inside towards the top of the opening and you should feel a circle like button. That's the bypass. If it feels solid, it should be good.

One thing, I had a unit fool me a while back. What was causing the issue was about a year ago the owner has the spa resurfaced and they didn't bypass the heater. A bunch of crud starting clogging the heat exchanger. Once it clogged one of the tubes pretty good, clunking sounds started. I was able to flush a good portion of it our with a pretty strong water stream from a hose.
Click to expand...

Thank you!

The heater was installed without a bypass in the system at all (seems kind of dumb), so water which is flowing from the filter *always* goes through the heater. I checked just now, and pressure out the returns is good. I'll do as you suggest and pull out the thermal regulator (that's the part I was describing in my above post, thanks for the terminology) and see about the bypass. That sounds like a pretty good bet!

One thing: Since the water is always going through the heater and the return in the pool is good, does that mean the heat exchanger is definitely not clogged? It seems like that would be the case to me since by definition the water flow is definitely flowing really well through that area, but I'm not sure if I'm getting the full picture.

In other words, the system loop is pump -> filter -> heater -> pool without any Jandy valves or anything to isolate the heater. You can sort of see it in the video I posted, or I can take a picture of the system if my description is too horrible (which it kinda is). :)

Will check on that bypass valve - be back in a bit! Thank you again!!

dave
 
It isn't a requirement to have a manual bypass in the plumbing. It's no problem not having it either. If you have good flow thru the heater then I suspect bad internal bypass or bad thermal regulator. Or both.
 
ps0303 said:
It isn't a requirement to have a manual bypass in the plumbing. It's no problem not having it either. If you have good flow thru the heater then I suspect bad internal bypass or bad thermal regulator. Or both.
Click to expand...

So - experiment conducted. The thermal regulator is pretty much brand new (I replaced it myself a month ago). I pulled it out and it didn't come straight out, but it was because something was caught - it looks like the wrapping on one of the pool filters (the paper cloth band that runs horizontally around the filter to keep it together) must have let go at some point, and it travelled through the pipe and to the heater. It's now pinched on either side of the internal bypass valve. That valve must have tried to open at some point, letting the paper wrap travel part way through, then closed up again.

Try as I might, I can't get it all out of there. The valve *seems* to be in okay shape, but I can't get it to pull down at all, so that paper stuff is wedged in there good.

So, I suppose the next question: How reasonable is it for someone like me (I can do light car repairs like changing alternators/brakes/water pump/etc) to pull off that manifold and clean the whole thing out? Can I leave the heater as it sits with its gas and electrical still connected, just undo the series of bolts that run on either side of the intake and discharge water ports and pull the thing off, clean it out and replace it, or it more difficult than it looks?

In looking here:

Part Diagram

I do see the manifold (part #9, I think) connects to a series of parts before it gets to the heat exchanger. Is it as simple as unscrewing the two water ports, taking off 8 bolts and popping the thing off, or will really bad things happen if I do that?
 
Sounds like maybe the paper band is caught in a way that it could be causing your noise issue. If you're trying to pull on the bypass, it won't happen. It is pretty tight to begin with.

Yes it is that simple as long as you have room. Even if you just have to rotate is a few inches so once you remove the bolts you can remove the manifold, you're good. When you put it back together, make sure to lube the o-rings. Hopefully the o-rings on the ends of the tube sheets are in good shape because if not, it will leak when you put it back together.
 
ps0303 said:
Sounds like maybe the paper band is caught in a way that it could be causing your noise issue. If you're trying to pull on the bypass, it won't happen. It is pretty tight to begin with.

Yes it is that simple as long as you have room. Even if you just have to rotate is a few inches so once you remove the bolts you can remove the manifold, you're good. When you put it back together, make sure to lube the o-rings. Hopefully the o-rings on the ends of the tube sheets are in good shape because if not, it will leak when you put it back together.
Click to expand...

Okay! So, looks like we have a potential winner.

Pictures attached... :)

First - the backside of the manifold. Looks like there's something inside...

View attachment 39350

Undoing the back part of the manifold, you see this:

View attachment 39351

That's removed. Popped off the valve just to check - I think it looks okay - would love an opinion:

IMG_20150705_151434.jpg IMG_20150705_151424.jpg

..so, I'm putting it all back together. The O-ring looks like it might be a little old, but I'll give it a shot and see how it goes.

Whether or not that was the cause of the issue, that was certainly something that needed to be resolved. :) Thank you for your help, PS0303!!

Hopefully, the thread will be valuable to someone in the future.
 
ps0303 said:
Yeah a bet that was your issue.
Click to expand...

Rats. It ran for about an hour, then tripped to "Service Heater". I didn't hear the noise, which I suppose is progress, but something's not quite right, obviously.

Pulled off the top - AGS light is on again. I have replaced both the HLS and AGS switches over the past year, and the previous owner did the Thermistor in 2013. I replaced the thermal regulator within the past couple of months. Man, I'm struggling, here, and I'm not sure what to do next. Do you have any more thoughts?

I suppose it COULD be that valve, but it seemed like it worked (it opened and closed, etc), but I don't know how it's supposed to "feel".
 
Well it could be a bad control board. If the heater fires and runs for a period of time, it would very unusual for the gas valve to stop operating while heating.

If it were me, I'd pull another system board out of my van and plug it in.
 

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That Obstruction is the "wrap" that you find on the filter. Take the filter top off and remove the rest of them. They are only necessary during production of the filter element(s). I would do a quick check of the therm bypass to be sure that this has not happened there too. I would check/replace Fenwall before main board. While main boards do go out, your symptom points toward Fenwall.

Dave, to respond to your IM, like Paul, We have the luxury? of being able to go to the truck and get a board to see if that is the problem. Not an option for a lot of techs, but at times, it sure saves time. Often here on the forum, I hesitate to tell DIY'ers to "just go out and get one and try it", obviously due to the cost.

I would,
1. Check therm by-pass.
2. Fenwall
3. Main board
BUT THIS IS JUST WHAT I WOULD DO.
Thermal bypass is a water issue affected by water temp and/or its own operation. If you are getting AGS or Hi Limit, i dont think it is 2 or 3. Those two tell main board to shut down, and rarely go bad, so water temp is really getting too hot, and you should look in that direction.
Main board gives instruction/signal/voltage to the Fenwall that controls the gas valve. Either Fenwall is closing gas valve (rebel) or it is following instruction from Main board (loss of voltage).

As always, check all wiring for third party interference! As heat rises inside the heater jacket, resistance goes up on almost chewed through wiring. So what would give "good enough" continuity cold, may not when internal temps go up. Bet you didn't think of that huh?

Neither did i for the first hour chasing my tail one hot afternoon...
 
Sorry for the delay - was out of commission for a few days.

Thanks very much to you both for the replies. So, my question: How do I know if the bypass valve is bad? I took it out, there were no cracks and the thing pushed up and down properly, so it seemed like it was "good", but I really have no frame of reference. I took a couple of pictures of it above. Or, is that the wrong bypass valve? I guess I'm thinking the manifold bypass valve is the same as the thermal bypass valve - is this wrong thinking?

And since I'm already blatantly flashing my ignorance... :) ... what's a fenwall?

Sorry for the novice questions, both of you. I really am grateful for your help and I promise, I'm googling to try to self-help before I become too much of a burden!
 
Aha - found it - ignition control module, got it.

Okay - so, given the order of part expense in ascending order, I'd like to check the thermal bypass first. Is this the same as manifold bypass, and is there anything beyond the obvious "wow, that's broken into three pieces" stuff I should check for? Is there an actual test of some sort I can run?
 
CanadaDave said:
Hi, everyone.

Last year, I moved into a home with a pre-existing concrete pool and spa (both connected to the main system, separated with Jandy valves). Among its equipment is a Sta Rite Max E Therm 400 heater, which is the problem child today.

The heater runs correctly when the system is set to filter only the spa. When the system is only running the spa, the pressure is much higher - approximately 30-35 PSI - because it only has one output for water to flow into the system, as opposed to 4 for the main pool. It typically runs about 20-22 PSI for the main pool.

When I have it set for the pool, it will run correctly for a seemingly random period of time.. sometimes an hour, sometimes 3 hours, and then it will make a fairly terrible noise as shown in the video below, do that noise for around 20-30 seconds, and fail with a "service heater" light. I've replaced several things on the heater because they were easily accessible and old - thermistor, water pressure switch, and thermostat/spring (whatever the term is - looks like a small car thermostat).

In fairness, it's possible that the spa setting would eventually fail as well. I've been in the spa for a couple of hours at times and never encountered it, but I've never tried running it for a full day or anything.

When it fails, it does appear to do a proper shutdown (the "vent" sound continues for a little bit, presumably to cool the heater down), and not some quick "panic" shutdown.

Here's the link to Youtube I managed to capture (sorry for the poor videography):

Here's a video of the problem actually happening.

Please don't pay attention to the pressure display on the pump during the video, as I was quickly trying to see if I could make the heater *not* fail by switching the system to spa very quickly, raising the PSI. While that noise was going on, the heater seemed to be physically vibrating/banging - I could feel it in the gas line and the heater shell, in addition to (obviously) hearing it.

Edit: Once "Service Heater" comes on (approx 45 seconds into video), the noise stops.

I'd love any thoughts people have on how to fix this. I'm still quite a novice with pools having never owned one before.

Thank you!
Click to expand...

I just got the 333k version installed this week. That sound is frightening for sure because I heard it yesterday when the heater was not valved in correctly and was not getting water flow. This happened within one minute of the heater starting and the temp shoot to 128. Then, it shutdown. I hope to never hear that sound again it is very traumatizing. Good luck troubleshooting.
 
Yes, that is the exact sound I heard. I laughed a little when your kid asked, what is that noise?

The temp took less that five seconds to start rising and it moved rapidly. So, if it happened, you would definitely notice.
 
CanadaDave said:
Sorry for the delay - was out of commission for a few days.

Thanks very much to you both for the replies. So, my question: How do I know if the bypass valve is bad? I took it out, there were no cracks and the thing pushed up and down properly, so it seemed like it was "good", but I really have no frame of reference. I took a couple of pictures of it above. Or, is that the wrong bypass valve? I guess I'm thinking the manifold bypass valve is the same as the thermal bypass valve - is this wrong thinking?

And since I'm already blatantly flashing my ignorance... :) ... what's a fenwall?

Sorry for the novice questions, both of you. I really am grateful for your help and I promise, I'm googling to try to self-help before I become too much of a burden!
Click to expand...

To answer your question how to know if the bypass is ok or not, if it wasn't OK it would be in pieces. Usually the button part has come off all together and thus it is broken. Yours sounds to be in good working shape.
 
Thanks, Paul.

So, I suppose we're past checking $30 parts and into rolling the dice on more expensive parts any way we look at this. My local service dealer only stocks a very limited amount of these and has told me that he needs to order either the ignition control module or the main board, and doesn't have parts to just try swapping something out. He also intimated that his plan would be the "well, you may have multiple problems, so if we replace both boards and it's fixed, I'm not going to take back the first board to try and save money". Fair in his position, I guess, since there just aren't that many of these in my area and he'd burn for the cost of the part, but sort of sucky for me. It's the drawback of a) not living in the US for stuff like this, and b) having equipment which is less common in my area, so parts aren't plentiful.

Question is: Given the above, which one to try? I'm not saying a $150 part will break me financially, but I definitely don't have unlimited funds, so I'd want to try one and then the other in the hopes that I'm not swapping both. Not trying to hold anyone to anything as I know we're into "try this and see" territory, and I really appreciate everyone's advice. Without it, I'd definitely be totally flying blind right now.

BTW - F3 - yeah, he was pretty rattled (hah!) by the whole thing. :) He's just a little guy and we've only been in the house for a year, so new noises are still something he's not fond of. :)

dave
 
Check Amazon. Confirm ability to return and order the board if they will take it back. You might lose shipping but at least not the entire cost of the part. You also get a few days to walk away from this ordeal.
 

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