adding a relay to operate a circuit

walt1122

Hi all, I've been trying to add a heating wire to heat up the water in our hot tub. I've wrapped the heating wire around the plastic pipe and it seems to work. I'm just testing it right now and I know it is a illegal connection. What I want to do is have it come on and off with the pump. I have a dedicated 20A for the pump so I'm thinking that shouldn't be a problem except I can't easily get to the internal wiring for the pump to connect the heating strip. Two different questions.
1. Is there a simple relay or some way that by turning on the pump it will signal the heating strip to come on? Poor analogy but like the mercury switch in a sump pump, When the connection is made at the switch it allows the pump to turn on?
2. If I can, I would like to pump up the voltage to the hot wire to 240V and put in a temperature switch so I can get the hot wire to really crank out the heat. I have a 30A wire I ran some time back for this purpose but I'm not sure how to put all this together so it is legal and can be done relatively cheaply. Any thoughts or suggestions would be appreciated

thanks

Walt

Pudge565

the question i would have is why isnt your hot tub heating itself is the heater broken?

chris75

Do you seriously think heat tape is going to heat your water? And I also have to ask whats wrong with the tubs heater?

walt1122

Hi guys, the tub doesn't have its own heater. I may have confused you with the "hot tub" thing. It is just a bathtub with a pump and water jets. And yes, I think I can heat the water or at least slow down the heat loss. I have roughly 20 feet of tape wrapped around the 1 1/2 - 2 inch primary tube that feeds the pump, using the 240V I'm getting a reading of 250+F on the outside of the insulated pipe so I gotta believe some of that heat is being transferred into the water. I'll put a temperature limit switch ( I have one ready to go) on the heat wrap so I don't get it too hot. If we do come up with some way of using the 240V and the 120V motor otherwise the heat tape still gets up to around 115F using the 120V circuit. Please remember I said I'm trying to keep the overall cost down. I have the tape and think there must be a safe way to make this happen. Just asking if anyone has a workable solution like a relay or some easy way to accomplish without making too much out of this.

thanks

Walt

nacko

they make heaters for jacuzzi bathtubs. they are made for the purpose and listed for the purpose, and therefore less likely to shock someone or burn the house down if wired properly. I suggest you look into that, and possibly hire an electrician for the task.

walt1122

nako, sorry you feel that way. Safeguards are in place. GFIC's are in place and code requirements are being followed. Heaters require cutting into the plastic plumbing and are resistance based in much the same manner as the heating tape I am proposing. The same issue, how to tie the heater in with the pump so it turns on and off with the pump will not change if I do it or if I get an electrician in to do it. I would rather not have the heater switch on some wall 6 feet away and need to remember to turn it on and off or have it on a timer and in either case forget to turn it off when the tub is drained. I'm hoping that the manufacturers of jacuzzi bathtubs have a way of testing if there is water in the pipe to keep from burning out the heating element otherwise that would be a problem all by itself. I'm thinking I would be more likely that I would remember to turn off the pump motor when I've finished bathing. So if the heater is incorporated in the pump circuit it would simplify the whole process. So thanks for your input but I think I will look to others for more meaningful and useful suggestions.

thanks

Walt

goose134

I have to say that this isn't a good idea. You sound like you've thought this through, and you have a good many safeguards to protect against electrical shock. My concern is for the equipment. And you. Let's not forget you.
The problem that you want to circumvent CAN be done. It's just a question of how effectively. The question that comes to mind: How will you regulate the temperature? Heat trace can be made to fluctuate, but be means of a triac and gizzies like that. I think the feeling is that you'd get more bang for your buck going with a factory ready assembly. I don't think anyone here doubts you COULD do it, but whether you SHOULD do it. I think it would behoove you to look into other alternatives.

Pudge565

why not just run some hot water in the tub with you in it? I whink that might work go the simple way.

jogr

Would a double pole double throw switch work?

walt1122

Hi goose134, I hear ya' I do have a temperature switch with a thermal couple lead on it that I had planned on securing to the pipe. When the preset temperature was reached the circut would would be broken thus protecting the plastic pipe from damage, when it cooled back down it would cycle on again. The heating wire has a resistance rating of something like 2 watts per foot so the likely hood of raising the temperature to a dangerous level is highly unlikely. I just wanted to keep the water from cooling off too quickly. But I guess I will listen to all your concerns even though I'm not sure I see the danger inherent in this design as it appears you all do. I just thought since I haven't kept up with developments in the industry I would find out if there are simplier and easier ways to do this without the bulky relays and circuts I remember.

thanks again to everyone for your input

Walt

frenchelectrican

I understand your conderasation about using the heater and there is quite few factory made heater some come in few diffrent size wattage rating some can be run on 120 v and other [ larger or powerfull units ] run on 240 volts and they are pretty compact in sizewise but unfortally i dont have any link to this set up ATM but you get the idea what i am talking about.

but check it out it may be a better alterantive way and safer to boot.

Merci, Marc