My spa heater does not seem to be heating the water. I adjust the temp until it just turns on and it will continue to run and not cycle on and off as it should. It is drawing current (the cables to the heater get hot to touch) but it does not seem to heat the water. I measured the resistance of the element and calculated the current (based on 1500W - heater power from schematic) and it came to 13 amps, but the element should only be drawing 9 amps (again from schematic). So I think the element is bad.

Incidentally I did have to repair burnt wiring in the control box (yes I double checked everything and all is connected correctly). Everything works except for the heater (which has the correct voltage (120v) across it).

Spa is a

Manufacturer: Gerico
Model: Citation #30
Year: I expect >1984 as that is the copyright year on the control box

Control Unit is a

Manufacturer: Ramco
Description: Spa-Temp Control System
Model: ST-1115A
Year copyrighted: 1984 (so this unit is >1984)

Heater (Specifications from the schematic diagram)
Power: 1.5K Watt
Current: 9 amps
Description of heater: Square box (grey) with single outlet into water flow, ~2" PCV pipe. Small dia Copper tube coming out of box connecting into same water flow tube, but from top (standard copper nipple connection). 2 electrical cable come from unit, one 3 wire (power), one 2 wire (high temp/pressure?). Both have 120v inputs across them. Resistance of 3 wires is 9 ohms (heater power); resistance of 2 wires is infinity (High pressure/temp?). According to the schematic in the control unit the "high pressure” sensor and heater are in one unit. There is a high temp reset on the bottom of the unit. It was tripped but I reset it prior to fixing the wiring and it did not do anything.

Hope this is enough information. I can send a pix of the unit if you need it. I think the element is fried, but don't want to replace it unnecessarily if that is not the problem.

Thanks,
Jim

It's heating.

You're probably just not giving it enough time, or don't have a cover.

Temp gain is approx 2 F per/hour WITH a cover.

Without a cover, expect several days...

btw, if the wires are hot to the touch, are you using large enough wire? All connections tight?

It has a cover (brand new in fact) and ran for 6 hours without a single degree increase in temp. When I repaired the wiring I use the same gage as was originally in the unit. When in doubt I used 12 gage stranded.

I found the heater information
Carlon
Cat# E987N

Hope this helps. Thanks for the reply.

Jim

If the heater is drawing amps, it's heating....period. Are you checking amp draw for the heater only, or perhaps the entire system. Jet pump not runing on high, right? Perhaps a bad thermometer you are using?

Let it run overnight.

Good luck!

~Swine

As you suggested I ran the spa for 4 days. The heater continued to draw current (11 amps measured into the heater). The temp of the spa remained at 72 degrees.

2 points -
The heater is only suppose to draw 9 amps, it is drawing 11 amps instead.
The thermometer that I am using is a standard glass thermometer which has been verified to operate properly.

I think the heater has an internal short. While this failure mechanism is very rare (generally the failure is an open) it can happen.

Are there any other tests you could suggest? If not, I think a new heater will fix it.

Jim

Are you *sure* the heater is drawing 11 amps, and it's not the pump? If the heater is drawing amperage, it's virtually impossible for the electricity to simply vanish.
If the heater has an internal short, it would *not* draw any significant current. It's very simple. That energy is being used, either as heat, light, or in some other form. A heater can't draw that many amps and not get hot.
Where are you taking the Amperage test? Are you sure the Amp meter is working correctly? Are you sure it's reading in F.L.A, and not milli-amps??

A 1.5KW heater at 120v will pull approx 12.5amps and ohm out around 9.6.... (OHMS LAW) as voltage in every home can very as much as 10%, the amperage will always vary as well.... The schematic isn't precise.... You have completed the most accurate test to see if a heater is working....
You can OHM out the heater, of couse, but if it gives you O/L, it is impossible for it to draw any signifigant amperage....

I'm sorry I can't tell you more... if the heater is drawing 13 amps, it's heating.....

I detached one of the wires that connects to the heater element and inserted an ammeter directly into the path. I am an electrical engineer as well as a home hobbyist and have been building and troubleshooting electronics for over 30 years. I did read the meter correctly.

Everything you say is correct, it should be heating. Unfortunately it is not despise the high current flowing into the heater element.

The only explanation I can think of is the element is shorted close to the base and there is not enough actual element surface area to make a difference in heating the water. I was hoping that I had missed something, but it doesn’t look like it.

Thanks again for the suggestions. I will let you know if a new element solves the problem.

Jim

I have to agree w/ Swine on this one, if you are drawing amperage, the heater is heating and you are loosing heat as fast as you are making it. Your description of how you are checking amp draw has me a bit baffled, all the amp meters I have seen, and used clamp around the wire to check for amperage, not to say that there isn't an amp meter that doesn't clamp over a wire, it's just I have never seen one.




Something does not add up.

huh? You need to keep the heater wired, and energized to check for Amps. When you say "detached one of the wires" you don't mean you disconnected anything, do you? If so, I don't think you are metering it out properly... Maybe you could explain it with a little more detail, or even a pic? :" title="Question" /> Good luck " title="Smile" />

http://www.doctronics.co.uk/meter.htm All of the ammeters I have used are inserted into the circuit in series. My spa time is limited, but cut my teeth (9 years) fixing aircraft avionics systems.

Sure use an inline AMP meter on a DC circuit, but we are dealing with AC here, you are not testing it correctly, sorry, you need a different meter. I have many years of service experience too, in different industries, and always when dealing with an AC circuit checking for AMP draw I have used a clamp on meter. I bet if we did a poll nearly every service tech on the forum would say they use a clamp on amp meter. IMHO

I'm not trying to pick a fight. I'm not saying that a clamp on isn't a good idea. I'm just saying that in some areas, the inline amp meter is used. Earlier in this discussion there was some suggestion that you couldn't disconnect the heater wires and run an amp meter inline. You said, "Your description of how you are checking amp draw has me a bit baffled, all the amp meters I have seen, and used clamp around the wire to check for amperage, not to say that there isn't an amp meter that doesn't clamp over a wire, it's just I have never seen one. " That's all I was commenting on. I think the difference here is that the clamp on is more suitable for high currents and the inline is good for lower curents. I've worked in the milliamp range on aircraft control systems, so I've only used the inline. I don't want to detract from the conversation...and I'm definitely here to learn from the folks here with experience.

So, what do you make of this problem? I agree that if the heater is pulling amps, there is heat (or rotation) being produced somewhere. If there is resistance on the heater and voltage on the terminals, it should be heating.

After looking over the whole thread, jbeffa says the spa is covered but them temp did not go up in 6 hours. We have not discussed if it is a portable with full foam and skirting or if it is an "in ground" spa. If its a portable with full foam and skirting, the temp should be raising. At 115 volts, the spa can be loosing the heat as fast as it is making it, hence the inquiry about a cover. If this spa in the ground, a 1.5kw heater is way too small. I don't believe the heater is drawing amperage.

First thanks for all the comments and suggestions, they have all been helpful.

The heater element was heating the water when electric current was flowing.

After some extensive troubleshooting I discovered that the heater control relay was bad. When I had the control panel open the heater would operate fine, when I closed panel the wires would torque the relay and break the connection (the relays for the spa are on section of the control panel that would "swing down" when I opened the control box). I had not thought to check the current to the heater element with the control box closed.

I discovered this by instrumenting the heater circuitry so I could measure the voltage going to the heater when the box was opened or closed.

I did remove the heater element and verified it was operating properly, which lead me on this troubleshooting odyssey. Replacing the relay solved the problem and the spa is now heating properly.

Again thanks for all the comments and suggestions, they have all been helpful.