Relay jumper disintegrated on Balboa VS500 board - advice?

[wes8398]

Of course, sub-zero temps hit last week, so my ~15 year old hot tub decided to stop heating the water. Working seven 12's currently, but managed to empty and blow out before things froze. Got to some electrical testing today to find 10.5 ohms and good continuity at the heating element, but no voltage to it when the board is commanding it. No voltage on the board side of the heater connection either. After a bunch of mucking around, I zoom out to look over the whole board and realise that a small-gauge jumper that runs between 2 relays is pretty much disintegrated... Falls apart when touched. A likely culprit to the no-heating, I figure. One of many things I don't know, though, is what might have caused this. Bad relays? Over-use due to a failed element being "switched on" for possibly many days consecutively?
Worth noting, the top side didn't show any error codes when it was running sans heat. Fuses are all good, 240 to the main terminal, pumps run fine, etc. I also didn't like the looks of the black-ish copper strap, and noticed some scorching on the back of the "bottom" relay.

Any insights from you fine folks?

 

[ajw22]

Let's see if @swamprat69 is familiar with that board.

 

[wes8398]

Another question... When wiring jumpers, is it ok to use solid copper rather than stranded? I've got some 14 awg home wiring lying around, but no stranded stuff.

 

[1poolman1]

Another question... When wiring jumpers, is it ok to use solid copper rather than stranded? I've got some 14 awg home wiring lying around, but no stranded stuff.

If that is the heater circuit, 14g is too small. You need at least 12g.

 

[wes8398]

If that is the heater circuit, 14g is too small. You need at least 12g.

Thank-you for chiming in. It is indeed the heater circuit. The jumper used on the doubled-up relays was 14ga (stranded), so I was just going with what was already there. There is a bad/melted solder at the output pin, which I'm sure is what destroyed that wire though. Maybe if it was 12ga, that wouldn't have happened... But probably not. I'll get some 12ga stranded and toss the 14ga solid jumpers that I made last night in the trash. Didn't like the way the connectors were holding on to the solid core anyway... Crimping really isn't good for solid core conductors, I've learned.

 

[RDspaguy]

Replace relays and jumper. A relay caused this.

 

[wes8398]

Replace relays and jumper. A relay caused this.

Do you figure the bad solder caused the relay issue, or the relay caused the solder to go bad? The board has tabs at each spot to run jumpers rather than use the board, so I've jumped all of the connections in order to leave the bad solder out of the equation. Was hoping that would do the trick. Put 9v to each relay individually and they all sound like they work as they should...

 

[dogsbody]

Stranded vs. solid wire can be a larger discussion, but not so much in this (simple) context. Generally, stranded is favoured for things like this (meaning: short jumpers, wiring inside a chassis, etc.) for the most obvious reason: Flexibility. If you're careful enough you can form a solid wire into exactly the right dimensions, but if it's not perfect it'll put stress on the terminals rather than flexing a little to compensate, which is what stranded does. And as you've noticed, crimping connectors onto solid wire doesn't work very well. But crimping isn't the only way to terminate them; you can solder the quick-disconnects to the wire and get results that are even better, but the heat is probably going to mess with the insulating sleeve. It's all a balancing act.

 

[wes8398]

Stranded vs. solid wire can be a larger discussion, but not so much in this (simple) context. Generally, stranded is favoured for things like this (meaning: short jumpers, wiring inside a chassis, etc.) for the most obvious reason: Flexibility. If you're careful enough you can form a solid wire into exactly the right dimensions, but if it's not perfect it'll put stress on the terminals rather than flexing a little to compensate, which is what stranded does. And as you've noticed, crimping connectors onto solid wire doesn't work very well. But crimping isn't the only way to terminate them; you can solder the quick-disconnects to the wire and get results that are even better, but the heat is probably going to mess with the insulating sleeve. It's all a balancing act.

Thanks for that. Any insight into my post above?

 

[dogsbody]

There are a bunch of posts, so I'm not sure what exactly you're referring to. If you mean into the nature of the failure, speaking as an EE who's brand new to this tub stuff, I'd say "something broke". Without dissecting it rather more intimately (i.e. cutting the relay apart to see how the contacts look), I'd probably agree with those who say "replace the relays and wires". I don't think the duty cycle (how many days of consecutive use, etc.) is likely to be at fault - these relays have a pretty healthy rating and should be fine. But stuff ages and contacts wear over the longer term and eventually fail. The hint for me is the discolouration of the board under the relay - that suggests that the contacts have been arcing and generating heat, which is a serious concern and connected to the wires burning up. But what I don't know is how the relays are organized - why there's a pair of them. Are they both on the heater, or does the other one drive something else?

 

[wes8398]

There are a bunch of posts, so I'm not sure what exactly you're referring to. If you mean into the nature of the failure, speaking as an EE who's brand new to this tub stuff, I'd say "something broke". Without dissecting it rather more intimately (i.e. cutting the relay apart to see how the contacts look), I'd probably agree with those who say "replace the relays and wires". I don't think the duty cycle (how many days of consecutive use, etc.) is likely to be at fault - these relays have a pretty healthy rating and should be fine. But stuff ages and contacts wear over the longer term and eventually fail. The hint for me is the discolouration of the board under the relay - that suggests that the contacts have been arcing and generating heat, which is a serious concern and connected to the wires burning up. But what I don't know is how the relays are organized - why there's a pair of them. Are they both on the heater, or does the other one drive something else?

Appreciate the feedback. I did put 9v battery leads to each relay, and they all seemed to be operating fine... But I'm not sure if that means they're fit for duty with the voltage involved with the heater relay. I'm sure the best idea would be replacing them, but that means a lot more down time, and also messing with soldering the board and such (which I'd rather not do). I'll Google some other ways the check the relays and see if they pass any other tests, then go from there.

 

[dogsbody]

I wouldn't suggest doing it that way - hearing the click means they're actuating, but that doesn' t tell you anything about the state of the contacts. Also, it's important to note that the voltage involved here isn't really material; the current that those contacts are carrying is. There aren't any tests you can execute on them that will give you meaningful information on how they'll perform under real-world load. They need to be replaced.

I understand your apprehension about tackling the PCB, and it's justified if you don't have the tools or experience. But it shouldn't be hard to find someone (locally) who can pull/replace them for you. I mean, you're flying the canuck flannel in your avatar; if you happened to be in my neighborhood I'd be happy to take care of it for nothing.

One other thing: I've never used Zettler parts, so I don't know how common they are or whether any other manufacturers make an equivalent - which matters in this case, because they look pretty tightly snuggled in there, so you're going to need relays with the same PCB footprint. That may take a little hunting and research. But the rule in electronics these days is "If it really matters, don't buy it from China", because the range of inferior counterfeits coming from over there is astounding, and this is not a case in which you want to screw around.

[edit]

Hmm... yeah, these guys have good distribution - Digikey lists this part for just a couple of bucks, but they don't normally stock it. So it'll take a little digging to find inventory or a cross, but it shouldn't be too hard.

 

[wes8398]

I wouldn't suggest doing it that way - hearing the click means they're actuating, but that doesn' t tell you anything about the state of the contacts. Also, it's important to note that the voltage involved here isn't really material; the current that those contacts are carrying is. There aren't any tests you can execute on them that will give you meaningful information on how they'll perform under real-world load. They need to be replaced.

I understand your apprehension about tackling the PCB, and it's justified if you don't have the tools or experience. But it shouldn't be hard to find someone (locally) who can pull/replace them for you. I mean, you're flying the canuck flannel in your avatar; if you happened to be in my neighborhood I'd be happy to take care of it for nothing.

One other thing: I've never used Zettler parts, so I don't know how common they are or whether any other manufacturers make an equivalent - which matters in this case, because they look pretty tightly snuggled in there, so you're going to need relays with the same PCB footprint. That may take a little hunting and research. But the rule in electronics these days is "If it really matters, don't buy it from China", because the range of inferior counterfeits coming from over there is astounding, and this is not a case in which you want to screw around.

[edit]

Hmm... yeah, these guys have good distribution - Digikey lists this part for just a couple of bucks, but they don't normally stock it. So it'll take a little digging to find inventory or a cross, but it shouldn't be too hard.

Thanks for the insight... Definitely shores up my decision to go ahead and replace the relays. I've done some soldering here and there for automotive purposes, but never on a PCB board. A few how-to's on YouTube, and I'm much less intimidated. One of the YouTube channels actually has a website and sells the zettler or equivalent parts I need (Set of (2) Relays, Zettler, T-90 Type, SPST, 15vdc, Coil, Balboa Board), so I'll probably support them given how helpful their content is.

 

[dogsbody]

Oooo... I don't know how well that's going to work. Price strikes me as kinda nuts ($11 USD each, vs. more like $2 from Digikey), but that's not too much of a consideration. If you're north of the border, anyone shipping by Canada Post is gonna be jammed up. But most of all it's the relay style that I don't like. The ones on your board are encapsulated. The new ones you linked to are not (they're what we'd call an "open frame" style). So even if they're plug-compatible (i.e. the PCB pins are in the same place as yours), I personally wouldn't use this style in an application in which water may get splashed around - I'd hold out for the fully-enclosed type. See if you can find those.

[edit]

I should add that another reason not to use an open-frame relay in a situation like this is because those contacts are carrying enough voltage to kill you, and any opportunity to cover an exposed hazard like that should be taken. Also, given that the top of the board is where one generally probes for signals and voltage, you should protect against an errant probe that might damage the probe, the thing being probed, and/or you.

 

[swamprat69]

Discoloration of the HTR2 connection at the circuit board is an indication of a poor/loose connection which would cause increased resistance and high heat at that point.

 

[wes8398]

Discoloration of the HTR2 connection at the circuit board is an indication of a poor/loose connection which would cause increased resistance and high heat at that point.

Straps were still torqued to spec upon removal... I think I'm going to replace the straps with leftover 10ga wire this time though.

 

[RDspaguy]

those contacts are carrying enough voltage to kill you,

Code requires gfci protection on spas. If wired properly you cannot electrocute yourself with your spa anymore.

Discoloration of the HTR2 connection at the circuit board is an indication of a poor/loose connection which would cause increased resistance and high heat at that point.

95% of the time the contacts on the thermostat relay, which actually turns the heater on and off during normal operation (the other 2 are high-limit relays and always closed unless there is an overheat), wear out and get hot from a poor connection and overheat the nearby circuitry. You will see heat damage to solder points, terminal connectors, and the copper strip (usually only 1 side). It is possible to have a loose or corroded connection be the heat source, but it's usually the relay contacts that start it off and burned solder that shuts it down.

 

[wes8398]

Code requires gfci protection on spas. If wired properly you cannot electrocute yourself with your spa anymore.


95% of the time the contacts on the thermostat relay, which actually turns the heater on and off during normal operation (the other 2 are high-limit relays and always closed unless there is an overheat), wear out and get hot from a poor connection and overheat the nearby circuitry. You will see heat damage to solder points, terminal connectors, and the copper strip (usually only 1 side). It is possible to have a loose or corroded connection be the heat source, but it's usually the relay contacts that start it off and burned solder that shuts it down.

Thanks for chiming in again. So you're saying the HTR2 relay (the one at the very bottom left of the board, connected to the red leg) is the one that turns the heater on and off? Would *that* relay going bad have caused the "bottom" HTR1 relay to overheat, discolor the board, and blow a solder connection (as pictured in the OP)? To be clear, it was the HTR1 strap that was discolored, but the HTR2 relay jumper that fried and blew the solder connection. Alas, all three have now been replaced, anyway...
Since draining the tub, blowing out the lines, and removing the control pack, it's been sub-zero temperatures here and I've been busy AF, so the tub's been sitting empty while I've been preoccupied with life outside of pretending to be a hot tub repair guy. I've managed to order new relays (got a 4 pack of the original sealed units from amazon for $30) and enjoyed some late night tinker time at the kitchen table with a glass of whiskey and my $20 harbor freight soldering iron one evening. Upon removal of one of the relays (the "top" one of the pair above the HTR2 connection), I accidentally pulled up 2 of the "small pin"'s through-hole pads. Unsure what the tiny traces from those pads led to - and whether or not they were required connections - I simply reinstalled the new relays and put an extra big gob of solder on the though-holes/traces that the pads came up on. I also replaced the single HTR2 relay (without any drama).
I've wanted to go hook things up and test (to see if my non-repair of the lifted pads mattered), but I'm not aware of a way to test full heater function without refilling the tub, which - in these temperatures - I don't want to do, in case of a failed repair and having to empty/winterize in a big panic again. I think the tub's going to have to sit empty until we get a stretch of a few days (that I'm free of kids, work, and all the other things that occupy my time) where the temperatures are above freezing and I can (comfortably) put things back together and test.

 

[RDspaguy]

So you're saying the HTR2 relay (the one at the very bottom left of the board, connected to the red leg) is the one that turns the heater on and off?

I'm saying only 1 relay of the three turns on/off under normal operation, the other 2 require an error to open, and that 1 is usually the cause of heat damage ANYWHERE IN THE CIRCUIT. Copper conducts heat as well as electricity.
I did not say which is which.

three have now been replaced

Which is what I recommend.

I'm not aware of a way to test full heater function without refilling the tub

A balboa pack will burn a heater out before realizing it's empty (Another source of heat damage, dry-fire). So you can test control functions by disconnecting the heater terminal strips and testing voltage. It'll try for a while before throwing an error code.

 

[wes8398]

I'm saying only 1 relay of the three turns on/off under normal operation, the other 2 require an error to open, and that 1 is usually the cause of heat damage ANYWHERE IN THE CIRCUIT. Copper conducts heat as well as electricity.
I did not say which is which.


Which is what I recommend.


A balboa pack will burn a heater out before realizing it's empty (Another source of heat damage, dry-fire). So you can test control functions by disconnecting the heater terminal strips and testing voltage. It'll try for a while before throwing an error code.

Thanks for the insight. Good to know I can test the relay replacement job out before filling the tub. Speaking of those terminal straps... Would you recommend against or in favour of replacing those straps with a couple inches of 10 ga wire with ring terminals? I was also thinking of utilizing all these jumper tabs that seem to be available to take the load off of the circuit board, so I have a bunch of leftover 10 ga wire anyway.