I have a very old spa.

It has a 120V circuit for everything, the pump and heater.

I had to do some repair on it yesterday. The heater was not heating,
which, as I realized, was caused by a crimp that worked itself
loose. Which I recrimped.

It seems to work, but still, the low power heater is very slow to heat
the spa at 120V.

The heater is switched on and off with a power relay (contactor).

The question that I have is this. Would it be sensible to add another
circuit to this spa, supplying 240VAC, that would power the heater
only. The old control system and pump would still be on 120VAC, but
the contactor would switch 240VAC going to the heater.

I would use a GFCI breaker on that 240V line, just like I have on the
120V line.

The only issue that I have with this possible change is that instead
of one breaker disconnecting the spa, there are now two. It may
present a possible hazard to someone attempting to repair the spa, as
they could turn off one circuit and forget to turn off another,
leading to possible electric shock.

Any thoughts?

i

Oh, and I realize that I would need a bigger contactor. No problem
here.

i

On Wed, 07 Jun 2006 13:18:18 GMT, Ignoramus31846 wrote:
I have a very old spa.

It has a 120V circuit for everything, the pump and heater.

I had to do some repair on it yesterday. The heater was not heating,
which, as I realized, was caused by a crimp that worked itself
loose. Which I recrimped.

It seems to work, but still, the low power heater is very slow to heat
the spa at 120V.

The heater is switched on and off with a power relay (contactor).

The question that I have is this. Would it be sensible to add another
circuit to this spa, supplying 240VAC, that would power the heater
only. The old control system and pump would still be on 120VAC, but
the contactor would switch 240VAC going to the heater.

I would use a GFCI breaker on that 240V line, just like I have on the
120V line.

The only issue that I have with this possible change is that instead
of one breaker disconnecting the spa, there are now two. It may
present a possible hazard to someone attempting to repair the spa, as
they could turn off one circuit and forget to turn off another,
leading to possible electric shock.

Any thoughts?

i

Ignoramus31846 wrote:
Oh, and I realize that I would need a bigger contactor. No problem
here.

i

On Wed, 07 Jun 2006 13:18:18 GMT, Ignoramus31846 wrote:
I have a very old spa.

It has a 120V circuit for everything, the pump and heater.

I had to do some repair on it yesterday. The heater was not heating,
which, as I realized, was caused by a crimp that worked itself
loose. Which I recrimped.

It seems to work, but still, the low power heater is very slow to heat
the spa at 120V.

The heater is switched on and off with a power relay (contactor).

The question that I have is this. Would it be sensible to add another
circuit to this spa, supplying 240VAC, that would power the heater
only. The old control system and pump would still be on 120VAC, but
the contactor would switch 240VAC going to the heater.

I would use a GFCI breaker on that 240V line, just like I have on the
120V line.

The only issue that I have with this possible change is that instead
of one breaker disconnecting the spa, there are now two. It may
present a possible hazard to someone attempting to repair the spa, as
they could turn off one circuit and forget to turn off another,
leading to possible electric shock.

Any thoughts?

i




It's hard to recommend doing this without seeing it, knowing your skill
levels, etc. Essentially, you are modifying a std power pack, which
is likely UL listed, and turning it into something else. Another
problem is if say a future owner or even you calls a service guy, who
now has a kludge to deal with and may not service it.

If you do do it, I would install a 240V GFCI that becomes the single
breaker for the whole SPA. You can then use 240V off that for the
heater, 120V off that for the rest of the SPA. That's how my spa is
set up. Also make sure that all metal bonding of the spa is maintained.

Bud-- wrote:
Ignoramus31846 wrote:
Oh, and I realize that I would need a bigger contactor. No problem
here.

i

On Wed, 07 Jun 2006 13:18:18 GMT, Ignoramus31846 wrote:

I have a very old spa.

It has a 120V circuit for everything, the pump and heater.

I had to do some repair on it yesterday. The heater was not heating,
which, as I realized, was caused by a crimp that worked itself
loose. Which I recrimped.

It seems to work, but still, the low power heater is very slow to heat
the spa at 120V.

The heater is switched on and off with a power relay (contactor).

The question that I have is this. Would it be sensible to add another
circuit to this spa, supplying 240VAC, that would power the heater
only. The old control system and pump would still be on 120VAC, but
the contactor would switch 240VAC going to the heater.

I would use a GFCI breaker on that 240V line, just like I have on the
120V line.

The only issue that I have with this possible change is that instead
of one breaker disconnecting the spa, there are now two. It may
present a possible hazard to someone attempting to repair the spa, as
they could turn off one circuit and forget to turn off another,
leading to possible electric shock.

Any thoughts?

i


To heat the water faster you would need a higher wattage heater. The
same wattage heaters will draw half the amps at twice the voltage.
Otherwise voltage doesn't matter.

Voltage does matter. The same heating element will produce 4 times the
power at 240V, compared to 120V, which is exactly what he wants, so the
water heats faster. Many water heating elements are made that are
rated to run at either voltage, they just produce more heat at the
higher voltage.


Could the spa handle higher heat production?

Almost certainly yes. SPAs that heat at 120V take just about forever
to warm up. Even with 4X the heat, it still takes hours. Some small
spas are sold in virtually identical config for 120V or 240V, the only
diff being that 240V goes to the heater.


You would, in effect, be
re-engineering the spa. I personally would be very unlikely to change
parts on a spa given potential safety problems. And if it is UL listed
now it wouldn't be after.

bud--

In article , Bud-- wrote:


To heat the water faster you would need a higher wattage heater. The
same wattage heaters will draw half the amps at twice the voltage.

That's because a heater that delivers, say, 1200W at 240V is *not* the same as
a heater that delivers 1200W at 120V. A heater operated at 240V delivers four
times the power as _the_same_heater_ operated at 120V.

Otherwise voltage doesn't matter.

Try again.

Suppose the heater delivers 1200 watts at 120V. Thus it draws 10 amps, and, by
Ohm's law V = IR, its resistance is 120 volts / 10 amps = 12 ohms.

Now push 240V through the same heater. Again, V = IR, where V = 240 volts and
R = the same 12 ohms... thus I = 20 amps.

Now calculate the power... P = IV where I = 20 amps and V = 240 volts... P =
4800 watts.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

On 7 Jun 2006 07:25:18 -0700, wrote:

Ignoramus31846 wrote:
Oh, and I realize that I would need a bigger contactor. No problem
here.

i

On Wed, 07 Jun 2006 13:18:18 GMT, Ignoramus31846 wrote:
I have a very old spa.

It has a 120V circuit for everything, the pump and heater.

I had to do some repair on it yesterday. The heater was not heating,
which, as I realized, was caused by a crimp that worked itself
loose. Which I recrimped.

It seems to work, but still, the low power heater is very slow to heat
the spa at 120V.

The heater is switched on and off with a power relay (contactor).

The question that I have is this. Would it be sensible to add another
circuit to this spa, supplying 240VAC, that would power the heater
only. The old control system and pump would still be on 120VAC, but
the contactor would switch 240VAC going to the heater.

I would use a GFCI breaker on that 240V line, just like I have on the
120V line.

The only issue that I have with this possible change is that instead
of one breaker disconnecting the spa, there are now two. It may
present a possible hazard to someone attempting to repair the spa, as
they could turn off one circuit and forget to turn off another,
leading to possible electric shock.

Any thoughts?

i




It's hard to recommend doing this without seeing it, knowing your skill
levels, etc. Essentially, you are modifying a std power pack, which
is likely UL listed, and turning it into something else. Another
problem is if say a future owner or even you calls a service guy, who
now has a kludge to deal with and may not service it.

If you do do it, I would install a 240V GFCI that becomes the single
breaker for the whole SPA. You can then use 240V off that for the
heater, 120V off that for the rest of the SPA. That's how my spa is
set up. Also make sure that all metal bonding of the spa is maintained.


Here's where I am confused. How do 240V GFCI breakers work? By
comparing currents going through two legs? If so, how can I power 120V
devices, that would naturally give off some current to neutral, and
yet not trip the GFCI?

i

Ignoramus31846 wrote:

Here's where I am confused. How do 240V GFCI breakers work? By
comparing currents going through two legs? If so, how can I power 120V
devices, that would naturally give off some current to neutral, and
yet not trip the GFCI?




There are two types of 240V GFCI. One only checks the current flow
between the two hots. It will trip if you try to use it with a neutral
and pull 120V off one leg. The other type includes neutral protection
and compares all the current flow. That's the one you want.

"Ignoramus31846" wrote in message
...
On Wed, 07 Jun 2006 09:39:41 -0500, Bud-- wrote:
Ignoramus31846 wrote:
Oh, and I realize that I would need a bigger contactor. No problem
here.

i

On Wed, 07 Jun 2006 13:18:18 GMT, Ignoramus31846
wrote:

I have a very old spa.

It has a 120V circuit for everything, the pump and heater.

I had to do some repair on it yesterday. The heater was not heating,
which, as I realized, was caused by a crimp that worked itself
loose. Which I recrimped.

It seems to work, but still, the low power heater is very slow to heat
the spa at 120V.

The heater is switched on and off with a power relay (contactor).

The question that I have is this. Would it be sensible to add another
circuit to this spa, supplying 240VAC, that would power the heater
only. The old control system and pump would still be on 120VAC, but
the contactor would switch 240VAC going to the heater.

I would use a GFCI breaker on that 240V line, just like I have on the
120V line.

The only issue that I have with this possible change is that instead
of one breaker disconnecting the spa, there are now two. It may
present a possible hazard to someone attempting to repair the spa, as
they could turn off one circuit and forget to turn off another,
leading to possible electric shock.

Any thoughts?

i


To heat the water faster you would need a higher wattage heater. The
same wattage heaters will draw half the amps at twice the voltage.
Otherwise voltage doesn't matter.

Sure, yes, I would definitely install a new heater instead of the old
one. The old one is rated 4000W at 208 volts (weird rating for a
household heater). Since it is running at 120 volts instead of 208, it
only produces 120*120/208/208*4000 watt or 1,300 watts.

Could the spa handle higher heat production? You would, in effect,
be re-engineering the spa. I personally would be very unlikely to
change parts on a spa given potential safety problems. And if it is
UL listed now it wouldn't be after.

I think that it could, the water flow through the heater is very
substantial. There is also a overheat prevention device on the pipe
that encloses the heater.

i

If you look carefully you may find that your heater element also has a 240
volt rating. It is common for elements to be rated for both 208 and 240
volts.

Don Young