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we discuss the main components of the heater circuit and the specific symptoms
that may be associated with each. Testing techniques and possible
fixes are listed.
Thermostat:
(Symptoms: no heat, too hot, not hot enough)
Mechanical thermostats consist
of a switch, control knob, and temperature sensor. The temperature
sensor looks like a copper wire when in fact it is a tube connected to
a bulb which is filled with freon which expands and contracts with temperature.
It is this expansion and contraction that activates the switch. If
your spa is too hot and does not respond
to a turning down of the thermostat, this bulb could be corroded.
Check it. If so, the gas may have escaped and thus while the switch
will activate you'll have no sensing capabilities so it won't turn off
at any designated temperature. Bulbs cannot be replaced. Time
for a new Thermostat. If your pump does not respond to thermostat
demand you may want to check through the thermostat with your meter on
ohms and power off to be sure the switch is opening and closing. You can
usually hear this if your ears are good. The switch will make a faint
click as it is engaged and disengaged. If it is engaging your problem
may be up or down the line. A power on check will assure you the
T-Stat is getting power. Meter to AC volts check each side to ground.
If your spa is not hot enough, you
may find that the thermostat is out of adjustment. If you remove
it from the heater (power off of course) you'll find an allen screw
adjustment on the bottom. a quarter turn clockwise will usually
increase the temperature to comfortable levels... A word of caution here.
It is UNSAFE to use your spa at temperatures above
104 degrees! It raises your core body temperature and
can cause flu like symptoms. It can also kill you! Even at
104 degrees you should limit your time in the spa to no more than 15 minutes.
Some people shouldn't use a spa that's hotter than body temperature.
Consult your doctor!!! Drugs and alcohol do not mix with spas either!
If you turn up your thermostat it's your responsibility to be sure your
spa is not too hot for safe use. Get a good thermometer that will
give you an accurate reading.
High
Limit: (Symptoms: no power, no heat, high limit trips too soon)
High limits are also temperature
sensing switches. They also use sensing bulbs so the same problems that
exist above can influence your high limit. If your high
limit is tripping within a few minutes of activating the heater
CHECK
FLOW! Little or no water flow will cause this. If it
trips
at the end of the heating cycle it's probably because at the
end, when the thermostat turns the pump off, the element is still
hot, and the water is hot. The temperature at the element can
go up for a few seconds and will sometimes trip the high limit. It's
best to replace the high limit if this happens all the time. The
high limit has an adjustment screw also. If you choose to try this
it is a counter clockwise turn and it should barely be tweaked. You
need
this safety switch to interrupt if there is a problem. This adjustment
is at your own risk! Remember flow is critical! If you adjust
your high limit and your pump impeller is full of leaves you could have
a complete meltdown of all pipes in contact with the heater. Not
a pretty sight! If you have no power
this can also indicate a "high limit tripped" condition.
Pressure
Switch: (Symptoms: contactor not closing, no heat.)
Obviously, flow is going to
come up again here! You must have flow for the pressure switch to
activate! To check for activation: with power off, disconnect
the leads going to the pressure switch. Make sure they aren't touching
anything. Power up and turn on low pump. With your meter on ohms,
check across the poles of the switch. You should have continuity. If not
and you know flow is not the issue, most pressure switches have
an adjusting collar that will vary the pressure it takes to activate it.
Counter clockwise turns decrease pressure required. Turn the power
off before attempting any adjustment! Make all adjustments
slowly and try again. WARNING, if you
go too far the pressure switch may activate with the pump off. This
is the last thing you want to happen!!! Always check to be sure that
the heater goes off when the pump does! If you are certain
flow is present, but your pressure switch isn't activating you may want
to remove it and be sure no debris is clogging it up. Pressure switches
are in contact with the water, when you remove it water will come out (or
should). Power off! Close valves. Sometimes the location
of the pressure switch is such that removal is impossible without removing
other components (I hate that!) Some use a plastic base and must be unscrewed
very carefully or the darn thing will break off. Now you'll have to dig
out the old threads and replace your switch.
Flow
Switch: (Symptoms: GFI trips, no heat)
I haven't said too much about
these as they aren't as common as pressure switches. They are usually
in the plumbing close to the heart of the action. They are gray or
white with a small cord coming out of them that goes to the controller.
They utilize a little paddle type device that is pushed by water flow until
it activates a little switch. The switch should be isolated from
the water. If, when you open your flow switch water comes out, you
must replace it. Otherwise, with the power off remove the leads to
the terminals, make sure they aren't touching anything and power up.
With flow established check the switch to be sure it is closing using your
meter set on ohms. You should have continuity through the switch.
If not, time to replace. The wires, though small, carry 120 volts.
Don't leave them hanging.
Contactors:
(Symptoms: no heat, buzzing, GFI trips)
Contactors close when the
control loop is complete. They consist of a coil which when energized should
pull down the contacts so the voltage to the element can pass through.
Troubleshooting a contactor consists of checking across the coil (not the
contacts) to see if the circuit to it has been completed. Coils can
be 120 volt or 240 volt with 120 being the most common. This
is a power on test so be careful. With your meter set to AC volts
activate all controls necessary to activate your heater. Turn up the thermostat
to engage your low pump. Check across the coil of the contactor for
voltage (neutral and hot side for 120 volts). If you find the proper
amount of voltage present and your contactor is not engaging it is bad.
If you do NOT have voltage at the coil there is an open switch somewhere
in the control loop, you'll need to go back through your switches.
If your contactor is buzzing replace it. There may be more than one contactor.
Make sure you are checking the heater contactor by tracing back the wires
from your element.
The
Element: (Symptoms: GFI trips, no heat)
Before we start it is important
to note that if the spa is heating AT ALL it is
not the element. See thermostat. Assuming this is not
the case continue with the power off, disconnect all leads connected directly
to the element. With your meter on ohms test across the element terminals
for continuity. If there is no continuity your element is bad.
If you have continuity it should be around 9 to 12 ohms. If
your
GFI is tripping, check from ground
to each element terminal. The slightest flicker of continuity indicates
a fault to ground and your element is bad even
it it has continuity between the terminals. It may have
a pinhole in it or be otherwise corroded to where it is leaking current
to ground. This is a potentially lethal situation and your GFI is doing
it's job. Do not bypass GFI (ever!), if your element is leaking
or corroded.
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