Emerald Not Heating (Tech Help)

[Spiderman]

It's a seven year old Emerald and it's not heating.  Everything else works.  There is no resistance (0 Ohms) when checking the pressure switch.  Is the pressure switch the problem or could something else be causing it not to heat?  

[clover]

There are a series of switches that first must close before electric gets to the heater.  1) Thermostat request for heat (normally open), 2) high-limit switch (normally closed) (push in on reset button if there is one), 3) the flow switch or pressure switch (normally open).

If your flow or pressure switch is open, electric does not get to the heater element.  The question is, why would your pressure switch or flow switch not close, 1)enough water not running through system to close pressure/flow switch, 2) clogged or dirty filter that is restricting gpm flow necessary to close switch, 3) bad heater core element that has 240 volts to it, but is not heating because heater is "open" (bad).

Your switch is o ohms, so it is closed.  Take a voltage reading from one leg of the heater to the other leg of the heater.  YOU CAN NOT TAKE VOLTAGE FROM ONE TERMINAL TO GROUND which would be 120 volts on each terminal and add them together.  You either have 240 volts terminal to terminal, or 0 volts when you measure one heater terminal to another.

No 240 volts at the heater, check for 120 volts from both sides of the thermostat, hi-limit, flow/pressure switch to be sure 120 volts are traveling through the respective switches.  120 volts on one side and not the other identifies your problem.  

Because you are working with leathal voltage, I would recommend checking things over without touching anything you are not familiar with.  This is a good time to call for service, unless you are familiar with and able to work with electricity to follow the voltage.

[Jacuzzi Jim]

 Or you could just take the two wires off the pressure switch, and touch them together. If the heater comes on, its most likely the pressure switch.

[Spiderman]

There seems to be no flow restriction as the jets are working normally.  The thermistat is presumed to be working as I'm getting a temp read out on the control panel of 64 F, which seems right.  The theristat and hi-limit both register resistance; one is 44KOHMS and the other 40KOHMS.  There is no voltage at the heater terminals, which is from the pressure switch being open.  The owner already replaced the element, thinking that was the problem.   When I disconnected the pressure switch, the panel showed  a  "FLO" error message.  With the info I've described, is this enough to say the problem is the pressure switch?  

[clover]

Spiderman, the answer to your question is NO.  You say the "flow switch" reads 0 ohms which means the switch is closed, allowing the 120 volts to pass right through it going to the heater.  The other switches should also read 0 ohms.

Your'e doing great with ohms, but let's try volts.  The switchs that I described should all read 0 ohms when closed allowing 120 volts to pass in, out and through all three switches.  This is only one leg of the 240 volts needed to make the heater work.  One leg of 120 volts is constant and should be a fused circuit (check it).  The second leg is controlled by switches supplying the second leg of 120 v.  120 v on one leg meets the other leg of 120 v, and WALLA, that makes heat on request.  if you can follow 120 volts in and 120 volts out of each switch.  120 in, but no 120 out = bad switch.

Your circuit board is "reading" presumably the correct temperature of the water and the flow switch is responding correctly, disconnect the flow switch wires and you open the switch which sends the "FLO" message.  Short the two wires together and the switch represents 0 ohms or a closed switch.  This is not your problem.

Turn the power off and investigte the circuit board.  Look for "charring" on the heater terminals, circuit traces or relays.  Your spa has been in operation for 7 years and I would suspect the heater relays on the circuit board could be the problem.  Check voltage going into the relays and look for 240 volts coming out of the relays going to the black and red heater wires.

The problem is NO 240 Volts to the heater.  Find out where you are losing it and that is the problem.  Thermostat (not likely), Hi-limit (not likely), flow switch (not according to 0 ohms), No 240 to the heater = no heat.  You are probably not getting 240 coming out of the circuit board to the heater.  OR, CHECK your incoming voltage supply from the house.  Measure from Line 1 and Line 2, it should be 240 volts.  Please confirm.  Everything on your spa could be running on 120 volts with only the heater using 240 volts.

[Pathfinder]

Dont disconnect the pressure switch. You need to jump the switch the see if it is working, so either use a piece of wire and place it on both connections of the pressure switch or a simple screwdriver across the connections.  When you jump the switch and your heater light comes on it means you need to replace the switch.

[TubsAndCues]

There seems to be no flow restriction as the jets are working normally.   

Just because your jets work does not mean there is a flow restriction past the heater.  Your tub (just like all others except Hot Spring) has a bypass the filters to allow enough water to go through the pumps and produce ample jet pressure.

If there isn't enough water going past the heater, it probably won't work properly.  This is a problem I see in about 80% of tubs not heating.  Easy way to check it is pull the filters out.  If it's still not heating, then it's a technical problem (which is above my level of knowledge).  If it does heat up, you've got dirty filters.  Clean them with a filter cleaner/degreaser or buy new ones.  Our Emerald filters run $14 a piece, and you probably need 2 of them.

good luck!!!