Diagnosing No Heat With Balboa Controller

[endorfin]

My spa water heater stopped working this week. It uses a Balboa vs520sz spapack / controller that is original with the tub and in service for 3 years. It is wired for 240V. There was no refill or noticeable events before it failed. I think it is either the heating element or a relay on the board and looking for help figuring out.

• I have confirmed there is no issue with incoming power and water flow. Both pumps are working fine at full pressure.
• There are no error codes on the topside unit and i have reset the spapack.
• The heat light is coming on. I assume this means the board is not recognizing any problems / faults.
• What i don't know is if this light is wired to the heater terminal or somewhere earlier (before the power relay).

When the controller was calling for heat, i used a voltmeter on both terminals of the heating element which read 0. Shouldn't this have read 240? Does this mean there is a problem between wherever the heat light connects in and the connection to the element? Resistance terminal to terminal is 6 ohms which is about half what it is in the element for my 240v hot water heater.

Any thoughts?

Thanks.

[n1oty]

Sounds like at least a bad heater relay, but 6 ohms across the cold pins of the element is a problem. Did you isolate the heater before taking that reading??? If you did, the element should be replaced as well since it may be the cause of the relay failure. A 6 ohm element at 240 volts would draw about 40 amps. Most heater relays are rated to a max of 30 amps. 4kW elements should show about 16 ohms (+/-) and 5.5 kW elements should show about 11 ohms (+/-).

John

[endorfin]

John, oops, no i did not specifically isolate the leads before testing the resistance. I didn't expect there to be a complete circuit in the other direction and thought that it wouldn't matter.

I assume the relay being bad would be consistent with the heat light being on but no voltage at the terminals, right?

I'll retest with isolation. Assuming this is it, can the relay be replaced without replacing the whole board? Seems like i would save a lot of money.

Thanks

[Spa Board Doctor]

Yes, the relay can be replaced. Our contact information follows. http://www.spokanespas.com/html/pc_board.html

Thanks,

BB

[n1oty]

John, oops, no i did not specifically isolate the leads before testing the resistance. I didn't expect there to be a complete circuit in the other direction and thought that it wouldn't matter.

I assume the relay being bad would be consistent with the heat light being on but no voltage at the terminals, right?

I'll retest with isolation. Assuming this is it, can the relay be replaced without replacing the whole board? Seems like i would save a lot of money.

Thanks

It should already be isolated, BUT that assumes you do not also have a stuck relay. Never assume such things and just isolate the heater to be sure. Any resistance showing up in parallel will lower the overall circuit resistance via the equation R1 X R2 divided by R1 plus R2. Isolation by disconnecting both straps from the heater cold pins ensures that you are only reading the resistance of the element.

A bad relay is evidenced by NOT getting line voltage to the heater when everything appears to be calling for heat. Pro's with meters have a way of testing which relay is not closing. The switching contacts test just like any switch. I don't expect most homeowners to be able to troubleshoot to this level.

Relays are readily exchanged, IF the board is not damaged by the relay failure. If it blew violently, the board may not be salvageable. If the board traces are all good though, relay swap works great.

John

[Spa_Guru]

Spokanespas has repaired many boards for me, and not one of them has failed post repair.

[endorfin]

Ok, I have confirmed resistance on my heater is 10.5 ohms so i had a bad reading earlier. I also confirmed there is a constant approx 15V between terminals even when system is not calling for heat and according to Balboa, any reading between 0 and 25 is in "normal range".

When system is calling for heat, i am getting 120V to one terminal to neutral but not the other. I also read 240V to the opposite "hot". I have confirmed the problem is that the bottom of the 2 heater relays is not working. Maybe I’ll send this to Spokane Spas when I have more time - but their website says to return the full entire spa pack and top side unit and I don’t want to take out the water circulation until there is no longer a freeze potential.

So as a temporary solution or just hypothetically, could an electrician install a hot feed (fused) to the unpowered terminal using the good relay as the voltage trigger (the second relay is slaved off of the first anyway)? Assume this terminal is isolated from the circuit board. Seems like this would accomplish exactly the same thing as having a new relay soldered into the circuit board.

[Spa Board Doctor]

endorfin,

You absolutely can't bypass the failed heater relay. The "slaved off" relay is the high limit and does not switch on/off thermostatically. The heater would be energized immediately upon power-up causing the water in the heater tube to boil.

I can send you a SpaSaver (input power terminal block with a pump receptacle) so you can keep the spa circulating without concern of freezing. You can remove the spa controller and leave the heater in place so we can keep the water circulating while the board is being repaired. The cost of the SpaSaver terminal is $22.00. Also, in this case you don't have to send your spaside keypad. We have a test head for this type of equipment.

BB

[endorfin]

Thanks BB, this sounds great. will follow up with PM.