@bwilford
Can you provide any further details on the above info. Feel free to PM me, so we don't hijack @DangerBoy 's thread.
BTW, I checked out your blog. Nice!!
Thanks...
r.
Relay modification/upgrade possibility?
- Thread starter DangerBoy
- Start date
Can you provide any further details on the above info. Feel free to PM me, so we don't hijack @DangerBoy 's thread.
BTW, I checked out your blog. Nice!!
Thanks...
r.
@DangerBoy , I only skimmed through this thread, so if I repeat anything already mentioned, I apologize.
The redundant relays are a safety feature, as they can fail closed and potentially run the heater out of control. I have seen melted pvc on several occasions, and a fire once. Burned up the skirting on one side and melted the acrylic shell and everything in the control box. Fortunately, it was not near the house.
I have installed many 50 amp contactors fired by the heating circuit on circuit boards over the years. I can't say for certain that I have ever done so on an old HS like yours, but it's possible.
On a circuit board I will fire 2 contactors (redundancy is key) in parallel off of the heater circuit. The relays will last almost forever, as you are only pulling a fraction of an amp through them to fire the contactor coils. When they are soldered into an expensive or NLA circuit board, it is a fantastic idea.
The contactors get line voltage directly from main power connection, are fired by the heater circuit, and send main power directly to the heater.
In your case, with the relays and control circuits accessible, you could just fire the contactors directly off of the control circuits (thermostat and high limit) and get rid of the relays.
I usually mount them in a 6x6 plastic Jbox wherever I can fit it in the equipment bay. If you are using conduit for wiring and 12v coils be sure to run your control circuits separate from main power to avoid issues from induced voltage on the control circuit.
The redundant relays are a safety feature, as they can fail closed and potentially run the heater out of control. I have seen melted pvc on several occasions, and a fire once. Burned up the skirting on one side and melted the acrylic shell and everything in the control box. Fortunately, it was not near the house.
I have installed many 50 amp contactors fired by the heating circuit on circuit boards over the years. I can't say for certain that I have ever done so on an old HS like yours, but it's possible.
On a circuit board I will fire 2 contactors (redundancy is key) in parallel off of the heater circuit. The relays will last almost forever, as you are only pulling a fraction of an amp through them to fire the contactor coils. When they are soldered into an expensive or NLA circuit board, it is a fantastic idea.
The contactors get line voltage directly from main power connection, are fired by the heater circuit, and send main power directly to the heater.
In your case, with the relays and control circuits accessible, you could just fire the contactors directly off of the control circuits (thermostat and high limit) and get rid of the relays.
I usually mount them in a 6x6 plastic Jbox wherever I can fit it in the equipment bay. If you are using conduit for wiring and 12v coils be sure to run your control circuits separate from main power to avoid issues from induced voltage on the control circuit.
@RDspaguy I looked at replacing the two heater relays with 50A contactors but the ones I found were really expensive and out of my budget range. I was also thinking of mounting them in the original control box at that time and they were too tall to fit in there. Then I started thinking more along the lines of using three phase SSRs because they were considerably cheaper. Fortunately, I later learned that those inexpensive SSRs I was seeing were counterfeit and dangerous. I've since then contacted Fotek in Taiwan and they put me in touch with a distributor in North America who can hook me up with genuine 75A Fotek 3-phase SSRs which would be safe to use. The genuine ones are a fair bit more expensive than the fakes but still a fair bit cheaper than any new 50A contactor I've been able to find. I can find used 50A contactors for less than the price of the genuine 75A 3-phase SSRs so that could be another option. How expensive are the 50A contactors you've been installing?
In the midst of all this, one of the three NLA and pure unobtainium PC boards in my tub's 25 year old control box failed and the result was no call for heat. For the last several weeks, I've been limping along with my heater hot-wired so that I can turn it on and off manually using the 30A GFCI breaker in the tub's sub-panel. Everything else on the tub, including the circ pump, runs off the 20A GFCI breaker which is on constantly. So what I've been doing is going out in the evening, turning the 30A breaker on and setting a timer on my cell phone to remind me to check the tub temp after a certain amount of time. When I get the tub heated up to 106F or so, I turn the heater off and go for a soak a little while later. By the time I get out of the tub it's at about 103F and I leave the heater off until the next day when I repeat the cycle. With the HS being so well insulated, I find the temp has only dropped to about 96-98F by evening of the next day so I only have to turn the heater on for 1 - 1.5 hours each evening to get it back up to temp in time for my evening soak. It's a bit cumbersome of a system but it works and I am well aware of the dangers/risks involved so I'm always very careful to set alarms to remind me the heater is on and so far I have not left the 30A breaker flipped on long enough to overheat the tub. It's just a makeshift system but I can make it work as long as I have to as long as I'm diligent about setting my alarms when the 30A breaker is on.
During the time I've been in limp mode, I managed to find a guy selling off a slightly newer HS Grandee that had some leaks due to freezing. I made a deal with him and went over and stripped every part I could get out of the tub and he scrapped the rest of the tub. In the cache of parts I got a complete IQ2000 control system which I may try to install this weekend.
This new IQ2000 system still uses the same P&B 30A relays for the heater and heater interlock relays my old system did so I suspect it will be prone to the same problems my old system was. I'll run with it the way it's set up for a while to see how it goes. If I find the 30A P&B heater relays are failing as often as they were in my old control system, I'll circle back to my plan to replace them with something more robust.
If it comes to that, I think my options will be to either replace them with 75A genuine Fotek 3-phase SSRs or used 50A contactors but in either case, the relays or contactors will be placed in a separate box the way you do it. I will probably lean towards using the SSRs even though I'm aware of the heat management issues they will bring vs using the contactors. The reason I'll probably lean towards the SSRs is because I can use them in the Wifi enabled DIY control system I mused about creating in another thread I started and you commented on. That system would use a "smart" WiFi enabled dual channel PID temperature controller to control the water temperature. That PID could also work with the contactors but using SSRs would give it the ability to use its sophisticated programming to optimize the temperature control and achieve better efficiency and energy savings. Mechanical contactors cannot give it that ability. At some point I know the old used IQ2000 system I'm about to install will also fail and at that point I think I'll opt to go with the DIY WiFi control system I've been dreaming of rather than installing another used IQ2000 or IQ2020 system in the tub so having the SSRs already will make that transition a lot easier and cheaper.
First things first though. I first need to get the IQ2000 system installed and working and then I need to see if I continue burning up heater and heater interlock relays with that system so that replacing them either with contactors or SSRs is warranted and worthwhile. If the IQ2000 system runs as designed and doesn't fry heater relays frequently then I'll let it ride as is and won't worry about doing the heater and heater interlock relay upgrade.
In the midst of all this, one of the three NLA and pure unobtainium PC boards in my tub's 25 year old control box failed and the result was no call for heat. For the last several weeks, I've been limping along with my heater hot-wired so that I can turn it on and off manually using the 30A GFCI breaker in the tub's sub-panel. Everything else on the tub, including the circ pump, runs off the 20A GFCI breaker which is on constantly. So what I've been doing is going out in the evening, turning the 30A breaker on and setting a timer on my cell phone to remind me to check the tub temp after a certain amount of time. When I get the tub heated up to 106F or so, I turn the heater off and go for a soak a little while later. By the time I get out of the tub it's at about 103F and I leave the heater off until the next day when I repeat the cycle. With the HS being so well insulated, I find the temp has only dropped to about 96-98F by evening of the next day so I only have to turn the heater on for 1 - 1.5 hours each evening to get it back up to temp in time for my evening soak. It's a bit cumbersome of a system but it works and I am well aware of the dangers/risks involved so I'm always very careful to set alarms to remind me the heater is on and so far I have not left the 30A breaker flipped on long enough to overheat the tub. It's just a makeshift system but I can make it work as long as I have to as long as I'm diligent about setting my alarms when the 30A breaker is on.
During the time I've been in limp mode, I managed to find a guy selling off a slightly newer HS Grandee that had some leaks due to freezing. I made a deal with him and went over and stripped every part I could get out of the tub and he scrapped the rest of the tub. In the cache of parts I got a complete IQ2000 control system which I may try to install this weekend.
This new IQ2000 system still uses the same P&B 30A relays for the heater and heater interlock relays my old system did so I suspect it will be prone to the same problems my old system was. I'll run with it the way it's set up for a while to see how it goes. If I find the 30A P&B heater relays are failing as often as they were in my old control system, I'll circle back to my plan to replace them with something more robust.
If it comes to that, I think my options will be to either replace them with 75A genuine Fotek 3-phase SSRs or used 50A contactors but in either case, the relays or contactors will be placed in a separate box the way you do it. I will probably lean towards using the SSRs even though I'm aware of the heat management issues they will bring vs using the contactors. The reason I'll probably lean towards the SSRs is because I can use them in the Wifi enabled DIY control system I mused about creating in another thread I started and you commented on. That system would use a "smart" WiFi enabled dual channel PID temperature controller to control the water temperature. That PID could also work with the contactors but using SSRs would give it the ability to use its sophisticated programming to optimize the temperature control and achieve better efficiency and energy savings. Mechanical contactors cannot give it that ability. At some point I know the old used IQ2000 system I'm about to install will also fail and at that point I think I'll opt to go with the DIY WiFi control system I've been dreaming of rather than installing another used IQ2000 or IQ2020 system in the tub so having the SSRs already will make that transition a lot easier and cheaper.
First things first though. I first need to get the IQ2000 system installed and working and then I need to see if I continue burning up heater and heater interlock relays with that system so that replacing them either with contactors or SSRs is warranted and worthwhile. If the IQ2000 system runs as designed and doesn't fry heater relays frequently then I'll let it ride as is and won't worry about doing the heater and heater interlock relay upgrade.
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Contactor-DP 240V Coil - 50A
Heavy Duty Spa Contactor Relay - Double Pole (DPST), 240V Coil, 50A. Commonly used for heater circuits. Orders $100+ Ship Free!
www.spadepot.com
The IQ2000 uses the same relays, but you will notice they used both sets of contacts for one leg, thereby halving the amp draw through each. They last much longer that way, but are not infallible by any means.
The IQ2000 controller will not be easy to fit in the old style manual control setup, assuming that is what you have.
It is deeper and wider, and the framing will have to be adapted and the mounting bracket removed to get it in there. Then you'll need to devise a way to mount it. I guess you could frame it out to create the space. That wasn't really an option for me.
I just put a 94 jetsetter up for sale. The board was toast (like yours), so I gutted the pack and built an old-school relays and contactors pack, reusing the thermostat, high limits, and light dimmer only. Bought a push-button switch for the jet pump relay from the hardware store to replace the momentary contact button used by the circuit board and installed a manual timer for filtration in a 4s jbox mounted under cabinet above the circ pump. Eliminated the clean function. Wired for 120v 20amp (15 amp actual max current draw).
It has a system (main power) contactor on the high limit in the pipe with the thermostat, so an actual overheat kills everything. A pump/ heat ready relay controlled by the pump button or manual timer that disables the heater if the pump is engaged (a must for 20 amp operation). And a heat contactor controlled by the thermostat and heater high limit, so a low flow condition only shuts off the heater. Most systems would also have a flow switch or pressure switch, but HS has always relied on high limits for low flow protection. The circ pump and light both feed off of the system relay directly. Just your basic old-school spa control. My investment was around $100 for the 2 contactors, 1 relay, 1 push button, and a pump seal. The timer I pulled from an old pack I had laying around, but I could have used a plug in Walmart special with the addition of a receptacle and cord end plug for another $25 or so. Easy, cheap to fix, and will probably outlast me.
On my IQ2000 system they are using 1 P&B 30A relay as the heater interlock supplying load power to an identical heater relay. Both relays are handling both legs so the setup is identical to my previous control system and so should have the same problems. I'll run with the system as is for the time being and see if it burns up heater relays like the original lsystem did before deciding if I want to upgrade the heater relays.
The contactors you provided a link to are a great price and would be a good solution were it not for the fact that the coil voltage is 240VAC and I need them to be 12VDC. Slight incompatability there. If I could find similarly priced one with a 12VDC coil voltage, I'd seriously consider using them.
I managed to get the IQ2000 system installed and working over the weekend. Adapting the tub surround to fit the IQ2000 topside control was the biggest hassle but I managed to do it and when I manage to finish the cosmetic repairs that are still needed, it will look no too bad.
The contactors you provided a link to are a great price and would be a good solution were it not for the fact that the coil voltage is 240VAC and I need them to be 12VDC. Slight incompatability there. If I could find similarly priced one with a 12VDC coil voltage, I'd seriously consider using them.
I managed to get the IQ2000 system installed and working over the weekend. Adapting the tub surround to fit the IQ2000 topside control was the biggest hassle but I managed to do it and when I manage to finish the cosmetic repairs that are still needed, it will look no too bad.
I didn't search for 12v contactors, but assumed they would be about the same. You could always fire the 240v (or 120v) contactors with your existing heater circuit. Use the interlock relay for one contactor and the therm relay for the other. Since you are only pulling fractional amps for the contactor coils through them they will last forever.
@RDspaguy Now I'm catching what you're pitching! I hadn't thought of doing things that way but it makes perfect sense. I will definitely consider doing that. Thanks for the good advice.
@RDspaguy Well, the same thing happened with the replacement IQ2000 control system that's now in my tub that always happened with the original control system: the heater relay blew up again. This time it blew up real good. Those Potter & Brumsfield 30A General purpose relays just cannot handle the demands of Watkins' new 6KW spa heater. I don't know if they held up better with the original 5.5 KW heater my tub came with but they sure as heck don't hold up very long powering the 6KW heaters. They're just not up to the task!
For now, I'm going to throw another one of those 30A relays in there to get the tub heating again. It'll last several months probably but won't last a year. In the meantime, I've got one of those 50A contactors you suggested on its way to me. I'll retrofit my system with the contactor after it arrives and hopefully eliminate the failing heater relay problem for good. Thanks for putting me on to those contactors.
You may be interested to know that I found a much cheaper source for those contactors. You can get the exact same item for only $8 USD each out of China on AliExpress. Shipping to Canada was $8 USD on the first one and $5 each on subsequent ones via the ePacket option. I actually ordered 2 so I'd have a spare. You may want to start sourcing them from there if you're installing them frequently. You can probably make a bit more margin on them when you resell them to your customers. Here's the link:
US $7.95 |Hvacstar SA 2P 40A 208/240V Definite Purpose Contactor 2Poles 40FLA 208/240V AC Coil , DP Contactor, Air Conditioner Contactor|definite purpose contactor|air conditioner contactorcontactor 240v - AliExpress
Thanks again.
For now, I'm going to throw another one of those 30A relays in there to get the tub heating again. It'll last several months probably but won't last a year. In the meantime, I've got one of those 50A contactors you suggested on its way to me. I'll retrofit my system with the contactor after it arrives and hopefully eliminate the failing heater relay problem for good. Thanks for putting me on to those contactors.
You may be interested to know that I found a much cheaper source for those contactors. You can get the exact same item for only $8 USD each out of China on AliExpress. Shipping to Canada was $8 USD on the first one and $5 each on subsequent ones via the ePacket option. I actually ordered 2 so I'd have a spare. You may want to start sourcing them from there if you're installing them frequently. You can probably make a bit more margin on them when you resell them to your customers. Here's the link:
US $7.95 |Hvacstar SA 2P 40A 208/240V Definite Purpose Contactor 2Poles 40FLA 208/240V AC Coil , DP Contactor, Air Conditioner Contactor|definite purpose contactor|air conditioner contactorcontactor 240v - AliExpress
Thanks again.
Rattus Suffocatus
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One of the issues with relays (and Contactors, though less likely here) is that they have accurate ratings for current load but they can't survive hot switching on at that level. That is what it looks like happened there.
Good luck with the contactors.. hopefully they aren't optimistically rated like most Chinese parts are....
Good luck with the contactors.. hopefully they aren't optimistically rated like most Chinese parts are....
@Rattus Suffocatus Yes, the breaker had tripped so I reset it only to see a bright flash of white light and hear very loud pop/bang which, evidently, was the relay blowing up. Kaboom! Then I could smell burnt wire insulation.
Note to self: the next time I see the 30A heater breaker has tripped, open up the control box and examine the heater relays BEFORE flipping the breaker back on.
@RDspaguy uses those contactors on his customers' tubs and recommended them to me so I feel quite confident they'll be up to the task. If they were over-rated and not up to the job, he would know by now as I believe he's installed a good number of them.
I look forward to not having these repeating issues with failed heater and heater interlock relays. To get through a whole winter without once having to be out there replacing relays and repairing burnt/melted wiring is a goal I'm setting. Those contactors should be the way to that goal.
Note to self: the next time I see the 30A heater breaker has tripped, open up the control box and examine the heater relays BEFORE flipping the breaker back on.
@RDspaguy uses those contactors on his customers' tubs and recommended them to me so I feel quite confident they'll be up to the task. If they were over-rated and not up to the job, he would know by now as I believe he's installed a good number of them.
I look forward to not having these repeating issues with failed heater and heater interlock relays. To get through a whole winter without once having to be out there replacing relays and repairing burnt/melted wiring is a goal I'm setting. Those contactors should be the way to that goal.
That is some serious damage. I have only seen something like that on a short. Are you sure your wiring is correct?
I have never heard of so many relay issues as you have. I'm at a loss as to what could be causing this. Are your terminal connectors (on the wires) rated for 25amps? The yellow ones you buy at the hardware store are usually 20. What size is the wire? Is it discolored or melted?
I have never heard of so many relay issues as you have. I'm at a loss as to what could be causing this. Are your terminal connectors (on the wires) rated for 25amps? The yellow ones you buy at the hardware store are usually 20. What size is the wire? Is it discolored or melted?