Just fitted 3.0 balboa heater element filled tub switched on pump comes in but heater light not coming on could it be the pressure switch how can i test

First, balboa does not manufacture hot tubs! They make control systems for hot tubs. If you are no longer able to switch between modes, then your topside control panel buttons are dead or falling. But... Even if you are still in economy mode, spa should still heat up. Once a demand for heat is recognized, you have a "Heat Call" and heater should come on. Is the "heat on" light, illuminated? If so, water should be heating, if not heater element may be bad? A multi meter would be good here: is there proper voltage at terminals on circuit board to heater? If so, bad element! If no voltage, then heater is not necessarily bad, probably just fine, I would then look at sensors? Good luck

You have voltage across the element but no heat....

Disconnect one element connection and do a resistance/continuity test. Or use a clamp to measure running current.

yes it is possible

Balboa switched to using two temp sensors a few years ago. So you won't find a flow or pressure switch. One of your temp sensors may be bad. With out knowing which pack you have I can't do much else for you.
I had a few issues with retro fitting these packs in older hot tubs. If the sensors read more than 2 degrees in diffrence the pack will either give you a flow or overheat message. Depending on witch one reads higher. Try swithing them by swapping them where they plug in at the board. If your still getting the same error you may have a flow issue. If this proves to be the case you can plumb in a by-pass allowing some of the water past the heater. It's not recommended by balboa but has solved their temp sensor errors for me in the past.
Also try putting it in test mode. You'll have to look up how to do it for your model. This is done with a dip switch on the board. Then read what the temp reading on temp sensor one and two is. If the reading are more than 2 degrees apart and your absolutly sure the sensors are good create a by-pass. This will solve the issue. Also be sure to put a ball valve on your by-pass to allow for ajustment so that you can get the maximum flow thru the heater w/ out getting the HL error.

Bad heating element. Shut the power to the breaker off, disconnect the wires off of the heating element and then check for (ohms) continuity across the two element leads. If it show OL on the meter then you here is an open in the element and it will need to be replaced. Good luck.

Information on the care of your product and troubleshooting is available here:

http://www.oasisleisure.ca/customer_care/SpaCare.html

Did you have a recent power outage? It is necessary to reset the temperature after a power outage.

Check the temperature setting on your hot tub; if it has defaulted do to a power outage reset to the desired temperature. If it is still set at your desired setting and is operating at 68 degrees then there is a problem that is preventing the tub from reaching the set temperature.

Some possible causes and actions are:

Pull filter (see if light comes on) / Replace filter
Knife valves not fully open / Open knife valves

Pressure switch cut of calibration / Adjust pressure switch
Faulty Pressure Switch / Replace pressure switch

Air leak, check pump suction line / Tighten pump union
Heating element corroded / Replace element

Faulty control panel / Replace panel

Find the Manual for you specifc model for more explansyion on Troubeshootig.

There are two main items to check. I do not recommend them unless you are qualified to work with electrical. The 2 main things that this could be are:
1. Pressure switch failure( (hot tubs need a sensor to tell the computer when it is safe to operate. If the pressure switch is out, then it will not heat) if this is a hot tub with a 24 hour circulation pump, then the pressure switch would actually be a flow switch.
Fix: Replace pressure switch/ flow switch
2. Heater element failure. (This type of failure typically trips a GFCI breaker)
if the heater element is out, then it will short to ground causing the hot tub to shut down repeatedly.

Notes: Are there any trouble codes coming up on the display panel? these help out greatly when troubleshooting like this via- messages

check to see that the flow switch is working properly, it may not have enough flow on low speed to allow the heater to turn on. Make sure your filter/s is/are clean. If you have a pressure switch instead of a flow switch, it may need to be adjusted or replaced.