1993 hot spring spas sovereign not heating

[tominos]

hi all, brand new to the forum, and recently got my hands on a free hot tub, that doesn't heat. my background is in electrical/hvac so i figured i could get it running.. 

anyway, it is a 1993 hot springs spa sovereign model. takes a 20a, 120v circuit. the controls seem fairly simple, but it just doesn't seem to be heating properly. the circulating pump is running, but the water coming in and out of the heater is the same temperature. the hot tub draws 14 amps or so with the heater on, and .3 amps with just the circulator pump on. my question is, since the heater draws 14a, can it still be bad? how can it draw 14a, and not heat up? i've tested resistance between the heater terminals and i get about 10ohms. i've also had the heater element out and plugged it in for a second and it got really hot very quickly. so it does seem to work. any insights? 

[mrwrick]

Hi, I have a 93 Hot Spring Classic. Went through all the heater tests you have done, then finally found 2 other things: I pinched the exposed capillary tube for the new thermostat when juggling the control box and after replacing the new thermostat with another new one I found I had a bad heater relay and had replaced it with the wrong one. Alot of missteps but eventually got it going. I know the Soveriegn model is different from the Classsic, but the voltage is similar and I bet the essential heater/jet circuitry is also. Mine is set up for 110, so it will either heat or run jets. The relay that went bad was the one that alternates between heater and jets and I HAD REPLACED IT WITH THE HEATER-ONLY UNIT. (sorry, inadvertent caps) I had replaced the lower priced relay and of course I needed the more expensive one.  So, I think you need to test more components in the heater circuit and you will likely find the problem is not the heater.

[tominos]

hi mrwrick, thanks for the reply. i believe the heater relay is working because i'm getting 120v at the plug for the heater. if the relay wasn't activating, i would not get 120v at the heater plug. so it is calling for heat the whole time, and the heater is pulling 14 amps, but the water isn't getting any hotter coming out of the heater core. i'm just perplexed that it can still pull 14 amps of current and not heat. 

[Jersey Hot Tub Repair]

You verified that the elements get hot when current is applied.  And you verified that it's drawing amperage.  There's nothing else in that hot tub to explain a 14 AMP draw, right?

A 120V heater will heat up the water about 1-2 degrees per hour,. depending upon the ambient temperature.  You're not really going to feel "hot" water coming out of the heater.  The fact that you're drawing 14 amps proves that the heater is working.  Give it a while.

My guess is that by tomorrow morning, your tub will be noticeably warmer.

 

 

[tominos]

Hi scuba Dave. Checked it this morning and no change in temp. It's the craziest thing about the heater drawing 14 amps and not heating. There are no other loads running except the circulator pump and that draws .3 amps by itself. 

 

The thing is i have felt the water come out of the circulator pump before when the heater was working. And the water coming out was warm. But now the water coming out is not any different in temperature than the water going in. 

 

I know what you mean about the 120v 1500w heater not feeling very warm but it seems like it's not doing anything at all. 

[PreservedSwine]

Put a cover on the spa.  It loses heat faster than it can gain it without a cover.  

[Jersey Hot Tub Repair]

How are you measuring the amperage?  Are you measuring 14 amps at the heater wires with a clamp-on meter while the heater is turned on?

If the element is getting 14 AMPS, it should be getting hot.  If it's not, something's wrong - that energy has to be going somewhere.  A burned out element will not be contiguous and won't carry a load.

[Sebastian Hay]

If your tub gets too hot, it might go past its heat limit and stop heating altogether. If I am not wrong, there should be a high limit reset switch that you'll need to hit to get it heating again. Just adjust the temperature setting so it doesn't hit the limit. Mine was showing that it was heating on the top panel, but wouldn't start heating until I reset the limit switch. I had prior work done to it and the tech cranked the heat all the way up to test something and I overlooked it once we got it going again.

[tominos]

i am testing the conductor coming off of my breaker that is feeding the gfci 20a receptacle that feeds the hot tub. i'm using a clamp on style amp meter. a fluke t5-600. something is definitely wrong, i have no idea where the energy is going haha. i'm not able to test the leads coming directly off of the heater because it comes out of the heater into a chord then plugs into the control panel. i could pull the control box out and check the leads feeding that heater receptacle.

 

i'm thinking of replacing all the internals on this hot tub with the spaguts v2 pack to get a more powerful heater, and be reliable for a while. is this a good idea with a tub this old?

[Jersey Hot Tub Repair]

Sebastian's suggestion is a good one.  Make sure your hi limit switch hasn't tripped.

You're not checking the heater, you're checking the breaker.  You don't have to remove the control pack, just open it and clamp the heater wires where they go to the circuit board or relays, depending on what your control pack has.

 

[tominos]

ah yes, the hi limit switch is not tripped. i've checked it. on this model of hot tub, the control panel with all the knobs have to come off, and the control box has to be unscrewed and dropped out to look at it, since the cover is on the back side. why would they make a hot tub like this? 

 

not sure why the pic is upside down

[Jersey Hot Tub Repair]

Couple of observations.

First of all, a couple of days ago you said the water coming out of the circ pump was warm.   Just so you know, the water coming out of your circ pump is going TO the heater, not FROM the heater.  The circ pump suction is in the front, the discharge is the the side hose.

My guess is you've got a bad relay in that control box.  You're going to have to get inside and follow the wires and see what's closing when the tub calls for heat, and see if a relay's staying open.  There are probably one or two small relay's that handle the control signals from your thermostat and hi limit circuits that activate the heater realy. 

 

 

[tominos]

is it plumbed incorrectly? heres how i think it works right now, the pump sucks water from the floor drain on the right, then pumps it through the heater, out the heater to a port on the side of the tub, which is where i've been feeling the water temp coming out. 

 

i'm going to pull apart the box and check it out. 

 

[tominos]

ok, just checked it out again. pulled the box out. there is 120v on the line side of the contactor for the heater. when i turn the heat up, the contactor makes, and there is 120v on the load side of the contactor. both poles are pulling in. both the hot and the neutral show it pulling about 14 amps. i also checked the temperature at one of the brass gate valves i installed, of the water coming from the floor drain, and of the temperature leaving the heater to the port on the side of the tub, and i also stuck my hand down by that port to check the temp of the water coming out, feels like theres no difference. i used a thermistor to check the temp on the brass valves. 

 

here it is with the heater on, and the circulation pump running. 

can't upload any more pics, but its about 55 degrees coming from the floor drain, and then about 56 coming out of the heater. 

 

i think the heater is bad, i'm just more curious as to how it can draw 14 amps, but produce very little to no heat. 

[Jersey Hot Tub Repair]

>>>   i think the heater is bad, i'm just more curious as to how it can draw 14 amps, but produce very little to no heat.

One possibility, although your GFCI should have taken care of it, is that your heating element is shorting out through the water to ground.  With the heater disconnected from the control pack, check continuity between each heater lead and the metal can that the heater is in.  Maybe that 14 AMP is going to ground?

Something's wacky here.  The tub draws 14 AMPs.  The resistance you measured is consistent with a good heating element.  The water is heating up a degree from one side of the heater to the other, which I would expect if it were working properly.  (Even if you expect that to be slightly warmer, bear with me.)

Do we know that the heated water is going into the tub?  Eventually, the water in the tub should be 56 going into the heater and 57 coming out.  Then 57 in and 58 out.  Etc... etc.... until it's where you've set it.  Is it possible that because you're using a brass gate valve, it's conducting the heat away from the water?  It does become sort of a mini-radiator, although eventually the air in the equipment compartment would heat up and the tub should heat.  I've never seen a manufacturer use anything besides PVC for a valve, and that's a modification you've made on your own.

Where are you located?  Are you in Alaska or New Mexico?  What's the air temperature?  Do you have a cover on the tub?

When I check an element, I look for continuity, voltage and amperage.  You've got it all. Eventually, I guess you're going to have to try a different heater, but it's not making any sense to me how you can consume energy and yet get no result.