Pentair Heater Cutout problem

[jeffbg]

I have a mastertemp 400 pentair heater. It has been installed about 1 1/2 years. The last time we fired it up, it would start, run, heat for a bit, then cut out the flame, run for a bit, relight, run for a bit, shut down, etc.

From all I've read, it seems I may have a thermal regulator issue.

Furthermore, in reading the manual closely, it seems I should have a check valve between the heater and the chlorine generator, which I don't and which probably contributed to the issue. Do folks recommend a check valve at this location?

Thanks!

- Jeff

 

[Guest]

The salt system should be plumbed in after the spa bypass. That way the cell reversal (polarity) does not clear off the calcium in to your spa, where there is no way for it to be picked up (if it goes back through the pool returns the pool cleaner should get most of it). If you have a raised spa (or a lower equipment pad) then there will be a check valve which should stop water from checking back, and I don't know why you would need a check valve after the heater.

If you bought just the Pentair heater then you have a one year warranty. If you bought three or more pieces at the same time Pentair increases the warranty to 3 years. If it is a warranty issue, and you have coverage, I would call a warranty station to have them check it out.

I'm not sure that it is the thermo-coupler. You may have a flow switch issue that is reading back to the heater, or maybe a bad temp sensor which is giving incorrect readings. Why do you think it is the thermo-coupler?

 

[polyvue]

n reading the manual closely, it seems I should have a check valve between the heater and the chlorine generator, which I don't and which probably contributed to the issue. Do folks recommend a check valve at this location?

I, too, have read (though not in the salt cell manual) that a check valve is recommended between the heater and salt cell. The reason I think is to any prevent backup of hypochlorous acid to the heater core, where it could damage the elements. On my system, however, there is no check valve, but a 4 foot length of pipe after the heater return and before the salt cell. That may be enough to prevent any back flow of chlorine.

The salt system should be plumbed in after the spa bypass. That way the cell reversal (polarity) does not clear off the calcium in to your spa, where there is no way for it to be picked up (if it goes back through the pool returns the pool cleaner should get most of it).

Does this only apply to certain brands of salt cells? On my (1 heater) shared pool/spa configuration the salt cell is plumbed prior to the pool/spa split return valve actuator. This conforms to the suggested configuration in the Goldline Aqua Cell installation manual. I've never noticed calcium flakes or anything else except bubbles from the salt cell being disbursed into the spa (or pool, for that matter.)

 

[Guest]

The salt system should be plumbed in after the spa bypass. That way the cell reversal (polarity) does not clear off the calcium in to your spa, where there is no way for it to be picked up (if it goes back through the pool returns the pool cleaner should get most of it).

Does this only apply to certain brands of salt cells? On my (1 heater) shared pool/spa configuration the salt cell is plumbed prior to the pool/spa split return valve actuator. This conforms to the suggested configuration in the Goldline Aqua Cell installation manual. I've never noticed calcium flakes or anything else except bubbles from the salt cell being disbursed into the spa (or pool, for that matter.)

Do you have white plaster (I didn't check your sig before posting!)? If you do, chances are you have it but can't see it!

The intent of polarity reversal is to somewhat clean the calcium build up off of the cell. When it does that, it sends the calcium flakes back out to the pool and into suspension, unless they are too heavy, in which case the fall to the floor/steps/benches, depending on where return lines are placed. If the cell is plumbed ahead of the spa bypass, and depending on how much flow is diverted to the spa, then some of those flakes go back to the spa. Since there is no pool cleaner cruising around in the spa, the flakes settle and attach themselves to the horizontal parts of the spa.

I have seen the diagrams for where to install the cell, but experience tells me it is wrong I believe the manufacturers show it that way so that chlorine is introduced directly to the spa, not indirectly like it will with just turnover of the spa water to the pool during normal circulation. The "problem" is that there may be a little CYA (not cyanuric acid!) coming from the salt generator folks so that they can feel that they have addressed the sanitation of the spa. If most people add liquid chlorine or have a blue "floater" in the pool, then they do not introduce chlorine directly in to the spa either. And since salt chlorine generators are only in a fraction of pools, there really is no reason to think they need to be directly chlorinating the spa either!

We used to install the cells before the spa bypass all the time (since we were like sheep and just did like we were told in the manual, but didn't really think about it!), but have learned the hard way that it isn't "right"!

 

[polyvue]

I have seen the diagrams for where to install the cell, but experience tells me it is wrong I believe the manufacturers show it that way so that chlorine is introduced directly to the spa, not indirectly like it will with just turnover of the spa water to the pool during normal circulation.

Makes sense. The Goldline controller differentiates salt cell output between pool and spa configurations so that in spa mode one can set the salt cell operation level at a lower figure than pool mode. I've noticed that when I run in spa mode for the 8 hours or so it takes to heat the water to 100° F. (from <=50° in winter) that there is a surfeit of chlorine in the water. Even a 3% setting produces way too much chlorine for my little 750 gallon IG spa in the 8-10 hours I'm running the filter/pump. Unfortunately, if the unit were plumbed so that the spa is not chlorinated during this period, the chlorine level (starting at the same as the pool's) would not be sufficient. Spas, mine included, receive high bather load for the hours they are in use and I'm far less successful in the winter months in convincing guests they need to shower before entering what becomes in short order an isolated cauldron of heated bacteria! It seems there is no easy solution to maintenance of chlorine either way.

BTW, though I've not noticed any calcium flakes I do have white plaster, so perhaps that explains it.

 

[mas985]

I have mine before the spa bypass and I think you are actually better off that way. Spas should have a higher residual than a pool for two reasons. First the water is warmer so chlorine degrades faster and second because of the jets, PH tends to rise faster so chlorine needs to be at a higher level than the pool to be effective. This could be done by a separate floater or dosing but the SWG is much more convienent.

As for the calcium problem, I can see how that could happen and may even of happen in my spa but in the five years of running the spa with SWG, I have not seen an issue. The benches and floor is still quite smooth. However, there may be a couple of things I do which may prevent any problems. First, I tend to keep PH fairly low in the 7.3-7.5 range so even though I have a fairly high CH level of 700 ppm by the end of the season, the cell doesn't seem to scale up much nor release much scale. Second, I run the spa in bypass mode an hour a day so even debris on the bottom of the spa and benches seems to get mixed up and overflowed into the pool so this probably helps as well. I never have had to clean the bottom of the spa manually except during fairly heavy leaf fall so just running in overflow seems to keep things from settling.

To me, I think it is more important to properly chlorinate the spa and any calcium that may get released into the spa can be handled by other means.

I've noticed that when I run in spa mode for the 8 hours or so it takes to heat the water to 100° F.

Wow! What size heater do you have? My spa is about the same size and only takes about a half an hour to raise the spa 30 degrees.

 

[Guest]

I have mine before the spa bypass and I think you are actually better off that way. Spas should have a higher residual than a pool for two reasons. First the water is warmer so chlorine degrades faster and second because of the jets, PH tends to rise faster so chlorine needs to be at a higher level than the pool to be effective. This could be done by a separate floater or dosing but the SWG is much more convienent.

As for the calcium problem, I can see how that could happen and may even of happen in my spa but in the five years of running the spa with SWG, I have not seen an issue. The benches and floor is still quite smooth. However, there may be a couple of things I do which may prevent any problems. First, I tend to keep PH fairly low in the 7.3-7.5 range so even though I have a fairly high CH level of 700 ppm by the end of the season, the cell doesn't seem to scale up much nor release much scale. Second, I run the spa in bypass mode an hour a day so even debris on the bottom of the spa and benches seems to get mixed up and overflowed into the pool so this probably helps as well. I never have had to clean the bottom of the spa manually except during fairly heavy leaf fall so just running in overflow seems to keep things from settling.

To me, I think it is more important to properly chlorinate the spa and any calcium that may get released into the spa can be handled by other means.

I've noticed that when I run in spa mode for the 8 hours or so it takes to heat the water to 100° F.

Wow! What size heater do you have? My spa is about the same size and only takes about a half an hour to raise the spa 30 degrees.

Mark,

Do you have any discoloration on the bottom of your spa?

 

[mas985]

Do you have any discoloration on the bottom of your spa?

No. Pool and spa surfaces look pretty much the same and haven't degraded much since it was installed.

In fact, I haven't seen anything in the way of calcium flakes in either the pool or spa that others have from SWGs even though I have fairly high CH levels. However, I do try and keep CSI as close to zero as possible so that may help.

 

[Guest]

To me, I think it is more important to properly chlorinate the spa and any calcium that may get released into the spa can be handled by other means.

I guess it really depends on how often you use your spa and how it reacts. In my case, I run my circulation pump for 8 hours a day, every day. Allowing for a 6 hour turnover rate, I add the 2 extra hours in for cheap insurance! With a properly operating salt chlorine generator, I should be able to maintain a chlorine residual that is sufficient to handle the spa. I don't use my spa all that often, so I would rather take my chances that I would have enough chlorine in my spa as opposed to having the flakes all over my benches (I let mine go for a while to see how bad it would get, and to see what effect it would have on my PebbleSheen. It got to the point that I could not even see the stone on my benches anymore! A couple quick acid washes on the benches brought it back to new again though). Additionally, if I have it plumbed ahead of the spa bypass, then when I go to spa mode I am chlorinating the spa with the same amount of chlorine that I am using to chlorinate the entire pool!

In the end, I think it all comes down to preference. There is really no way that will work every time, for everybody. And, at some point, adding extra chlorine will be necessary under certain conditions. This may be one of those times.

I did notice that you have plaster in your pool. Do you have white or is it colored?

 

[polyvue]

Additionally, if I have it plumbed ahead of the spa bypass, then when I go to spa mode I am chlorinating the spa with the same amount of chlorine that I am using to chlorinate the entire pool!

Since there is no information about your pool in your signature I can only guess that you don't have the type of configuration/controller that allows you to separately tune the SWG output. Regarding run times, I don't know that it matters, but my turnover rate is about 3 hours. In winter, I run the pump/filter less than half of that time.

I've noticed that when I run in spa mode for the 8 hours or so it takes to heat the water to 100° F.

Wow! What size heater do you have? My spa is about the same size and only takes about a half an hour to raise the spa 30 degrees.

See my signature. I have a 75 amp 18 kW Tankless Water Heater (that's an electric immersion type, for you neophytes! ) It's an energy hog but I have little choice: no piped natural gas in my neighborhood, propane and lpg disallowed due to local code restrictions and setbacks (a typically tiny California urban lot size).

 

[Guest]

Additionally, if I have it plumbed ahead of the spa bypass, then when I go to spa mode I am chlorinating the spa with the same amount of chlorine that I am using to chlorinate the entire pool!

Since there is no information about your pool in your signature I can only guess that you don't have the type of configuration/controller that allows you to separately tune the SWG output. Regarding run times, I don't know that it matters, but my turnover rate is about 3 hours. In winter, I run the pump/filter less than half of that time.

I guess I'll have to go put my info in my signature now...... Sheesh, this is what I get for being lazy :-D

As for run times, I like to run mine a little longer since I don't like my pool to sit stagnant for so long. I run a pretty efficient pump (Hybrid X-2) so the cost is not that big of a concern. I just like to keep my water moving.

OK, off to update my signature.......

 

[mas985]

I did notice that you have plaster in your pool. Do you have white or is it colored?

White and yes, it is probably hard to see the flakes but I would think not so hard at night with the light on which is usually when we use the spa. I still don't think I get that much flaking but even if I do, since I don't see it or feel it, I doubt it really matters.

Also, the PS8 controller I have has two settings, one for the pool and one for the spa. The Goldline manual instructions suggest that the cell be placed between the heater and spa/pool valve so that you can have different settings for each. I usually set the pool for 4 ppm and the spa for 8 ppm (4 ppm boost) for a CYA of 80 ppm. I have found that when my kids and their friends use the spa , chlorine gets used up pretty quickly and if I don't have the boost, the water will turn nasty pretty quickly.

Also, you have peaked my curiosity. What is a Hybrid X-2 pump and do you have a link to one?

 

[Guest]

Also, you have peaked my curiosity. What is a Hybrid X-2 pump and do you have a link to one?

Here's a link to the pump: www.hybridpumps.com They use a VFR (variable frequency drive) and generate their own power once they are up and running by using the flow of the water. I am pushing all my return water for the pool, as well as the spa spillway and a large waterfall at about 2,100 rpm and just over 2 amps! Pretty neat little pump (I tend to test lots of stuff out on my pool to see what works and what doesn't! This is the latest pump test! Still trying to find the perfect piece of equipment, if it exists :lol: ).

 

[mas985]

Interesting, looks like they also make a retrofit unit which I was thinking of looking into or maybe even building my own.

 

[Guest]

Interesting, looks like they also make a retrofit unit which I was thinking of looking into or maybe even building my own.

Not real sure the VFD by itself has been doing so well....... Interesting idea though.

If you give them a call (Lisa and John) tell them I told you to call. Really nice folks.

 

[JasonLion]

Another issue with putting a SWG before the pool/spa split is that the percentage setting needs to be lowered when you are in spa only mode (since there is way less water getting chlorine added to it). An automation system will normally adjust the percentage automatically. If you don't have an automation system and run the spa for too long with the SWG on, the FC level in the spa can shoot way up, possibly enough to cause problems.