Pentair Minimax NT Heater

[bdavis1969]

Hi guys,

I have a spillover spa that is heated with a minimax heater. When I set the temp the heater kicks on and heats the water up about 5 degrees...and thats it. It will then continue in the heat mode but the water will not get any warmer. Any ideas?

 

[waste]

Welcome to TFP!!

Sounds like the heater thinks it has achieved the desired temp and stops heating. What temp are you looking for and what temp does the heater say the water is?

 

[bdavis1969]

I set it at 100 and it may get to 88 or so...actually heats less then 5 degrees. It also stops then starts again, when it starts there is cool water coming in.

But even when the heat runs when it reaches a certain point it just stops heating.

 

[bdavis1969]

Someone suggested I clean the burners? Could dirty burners be causing this?

 

[JasonLion]

What happens when you set it to 105? Do you see any error indications?

 

[bdavis1969]

Nope. It just runs for a bit (heating), then stops, recycles itself, then starts heating again. But it never warms the water past 4 or 5 degrees. I let it run for like 2 hours, it ran the whole time (stopping and starting), putting warm water in the spa but it "levels off" after a while, then it doesnt get any warmer.

 

[bdavis1969]

The overspill is running the whole time to....I suppose it could be dumping whatever hot water comes in back into the pool?

 

[JasonLion]

If the spillover is running, it won't be able to warm the spa up any further until it heats the entire pool up, which will take a very long time.

 

[bdavis1969]

Then I need to turn the overspill off? I dont think my pool guy plumbed my pool right....If I turn the overspill off then the spa fills up with water...

 

[JasonLion]

There should be two valves, one selecting where the pump gets water (pool or spa) and the other selecting where the water from the pump goes (pool or spa). To heat the spa you need to set both valves to spa only. If the spa is filling up, the pump must be drawing some water from the pool.

 

[waste]

You and Jason may have tumbled on to the right idea. But, I still want to know what the heater thinks the temp is

 

[bdavis1969]

Thanks guys. That makes sense. Last night I played with the valves, when I do have the spillover turned off the heater loses pressure and of course wont go through the startup. The only way to keep pressure on the heater is to have the spillover valve open....

 

[JasonLion]

That doesn't make any sense to me. Could you post a picture of your plumbing setup?

 

[bdavis1969]

Yes! I will try to get some pics at lunch and post them afterwards. Thanks again.

 

[bdavis1969]

Here is my pic..more if needed. Any help will be appreciated.

[attachment=0:7g0b7yiu]DSCN1526-2.JPG[/attachment:7g0b7yiu]

 

[JasonLion]

Wow, that is scary. Is it possible to get another angle on that maze of pipe? I can't quite follow everything.

I see two pumps, one three way valve, at least six ball valves, and what looks like four capped off pipe ends.

 

[bdavis1969]

Sure. Here is some other shots:

[attachment=1:vwxp4w5r]DSCN1522-2.JPG[/attachment:vwxp4w5r]

[attachment=0:vwxp4w5r]DSCN1526-2.JPG[/attachment:vwxp4w5r]

 

[bdavis1969]

The two red valves and the white one controls my pool jets and drain.

The small white one controls the spillover. He put a circulation pump on there that I have no idea what it circulates. Up at the top (not in pic) is the blower.

 

[bdavis1969]

Another angle:

[attachment=0:cbzli6ed]DSCN1523-2.JPG[/attachment:cbzli6ed]

 

[JasonLion]

I see three suction lines: the two red valves with a white valve between them that feed into the pump. One of those should be skimmer(s), one pool main drain, and one the spa main drain. If you try turning off one at a time you should be able to figure out which is which fairly easily.

There are either three or four return lines: the line at the base of the filter with a black valve, the output of the heater, the column of pipe going up towards the roof, and another one near the heater feed from the small white valve coming out of the three way valve. Again, a little experimenting should reveal at least what some of those four lines feed.

Right now water to the small pump at the bottom of the heater is turned off. The three way valve also appears to be set to have water to the heater turned off.