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spa only heats 1-2 degrees - I think it's a water flow issue

spa only heats 1-2 degrees - I think it's a water flow issue

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  #1  
Old 01-12-21, 06:30 PM
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spa only heats 1-2 degrees - I think it's a water flow issue

I'm a recent first-time owner of a spa that's about 20 years old, and I might be asking dumb questions but you have to start somewhere. I feel like the solution is right in front of me and I'm missing it. Appreciate your help in advance.

My spa is in the corner of my pool, served by the same system. You could heat the pool, but I don't. It's a remote location with a propane tank and it makes much more sense to me to get the hot tub hot and take a cold plunge now and then.

When I turn the system on, the heater fires up and stays on, no problem. It's generating heat and the chimney is hot. But even after leaving it on for an hour, the temperature only goes up by 1-2 degrees.

There's three intakes into the pressure tank just before the heater. They are marked "drain," "skimmer" and something that is no longer legible. I'm guessing the illegible one says "spa." The "spa" one, however, does not seem to be bringing in any water. There's a regular garden hose that is an optional offshoot from it (and only it), and I have not been able to make that garden hose get wet.

I drained the tub. When I had the actuator turned towards the middle position (the big nose on the actuator turned towards middle), a small stream of water came out of the hot tub jets. When I turned the actuator towards "spa intake," that stream stopped. Making me wonder if I misdiagnosed what the actuator does - if the big nose on the actuator is turned to something, shouldn't that turn it on?

Then I turned on the filter pump (pressure is about 15 pounds) and water gushed out of the hot tub jets. My friend thought the water was hot but it didn't feel hot to me. There was no draining from the hot tub: it got full and spilled over into the pool, like an "infinity pool" type of effect.

Ah-hah, I thought, the problem is that the water from the spa is not circulating and therefore not getting hotter and hotter. Maybe there's a blockage in the drain. I drained the tub again and unscrewed the drain caps, Nothing to report.

So then I thought maybe there's a hydraulic air-block of some sort. There's a spaghetti size irrigation tube coming off the main (combined) intake, just before it hits the pressure tank. As soon as I touched that, the top broke off in my hands and water started spewing out of it. Turns out there was a bolt jammed into the end of that tube and over time it had gotten fragile. Not going for gold, I pried the bolt out of the broken off piece and jammed it back into the new end of the tube. Which made me think more about a hydraulic air-block but I'm at the end of my (lack of) expertise.

Any suggestions? Many thanks.

Brian
 
  #2  
Old 01-12-21, 06:46 PM
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Welcome to the forums.

You got a custom setup there. Very hard to visualize.
If you can take a few pictures and post them we can comment further.
How-to-insert-pictures.

 
  #3  
Old 01-12-21, 06:58 PM
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The most likely scenario is that your pump is drawing cold water from the pool and sending it to the heater. It should be recirculating the hot water from the spa back to the spa. This would be caused by the suction valve actuator not rotating from Pool to Spa when the spa is running.

When you say "pressure tank", do you really mean "pool filter"?

As Pjmax said, we need photos. Get a wide shot showing the whole equipment pad and a couple of close-ups of the valves.
 
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Old 01-12-21, 07:39 PM
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PJMax and RocketJSquirrel:

I appreciate your quick response! Will send you pictures this weekend when I'm back at the property. I'm sure they will help, but they won't help that much, it's a pretty convoluted system and hard to take in.

RocketJSquirrel: "The most likely scenario is that your pump is drawing cold water from the pool and sending it to the heater. It should be recirculating the hot water from the spa back to the spa. This would be caused by the suction valve actuator not rotating from Pool to Spa when the spa is running."

Yeah I agree, it's likely that the actuator is not doing what I think it is doing. Two things on that: 1) the part I can see does turn automatically when I get the system going, and 2) it worked a few months ago and nothing has changed. But maybe the outside dial is no longer indicative of what is happening inside, similar to a crescent wrench stripping a bolt?

And as a newbie, I'm getting the terminology wrong so please do correct me. There's what I would call a "pool filter" which is a suction pump with filters on it. The next place the water goes, it's a fat 25 gallon (?) tank with a gauge on it that I called a pressure tank because I'm used to the bladder tanks on my well, but that's probably not the right name.

Brian


 
  #5  
Old 01-12-21, 07:43 PM
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A sand/diatomaceous earth filter would be a round metal tank..... possibly with a gauge on it connected via two pipes and a multiport valve. That would be the actual filter. No pressure tank used.
 
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Old 01-12-21, 08:37 PM
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thank you PJMax. So what is the gauge telling me? that there's something going through the system, should be impacted by the filter pump (which amps up the overall pressure) but it doesn't tell me that. This is a sediment settling tank and the gauge is not really all that useful?
 
  #7  
Old 01-12-21, 09:19 PM
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That's not a tank, that's your pool filter. If it has a multiport valve, which has several positions it can rotate to, in front of it, it uses either sand or diatomaceous earth as a filter medium. No multiport indicates a cartridge filter.

The pressure gauge is to tell you when to clean the filter. When the filter is freshly cleaned, you look at the gauge and remember the reading at that pump speed. That reading will vary from system to system. (My normal pressure is 8 psi.) When the pressure climbs a bit, say 20% or so, it's time to clean the filter. The gauge is also to alert you of over-pressure, which is unusual but highly dangerous. A filter housing can typically withstand up to 50 psi. Beyond that, it will explode.

Try searching the web to learn about pool equipment. Here's a well-known pool school.
 
 

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