On Dec 27, 10:54*pm, lesnpat wrote:
On Dec 27, 5:31*pm, wrote:





On Dec 27, 5:41*pm, ransley wrote:

On Dec 27, 3:22*pm, wrote:

On Dec 27, 4:10*pm, lesnpat wrote:

My spa is a 2002 Regency Spas, made by National Equipment Mfg. Corp.
The circuitboard system has no mfr. name anywhere. *There are both a
knob thermostat control on the box at the heater and a topside
pushbutton control at tubside. *The heater is electric Vulcan style
(flow-through 2" stainless tube). *Pump is 220v and heater is 110v.

The spa heats normally, but quits short of target because the topside
digital thermometer reads 5 degrees warmer than actual water temp. *Is
there a way to calibrate the digital system to get the reading in sync
with the actual water temperature?

I have a much older NEMCO spa, but the system may be similar. *With
mine, the system of measuring and displaying the temp is controlled by
the electronics inside the power pack and it's not meant to be user
adjusted. * *There are several pots inside the power pack that control
parts of the settings. *One of them does what you want. *I figured it
out by experimenting years ago, but don't know which one was which
anymore. *Plus your power pack is probably different. * I couldn't
find any info avail that detailed what's in the power pack or how it
works.

Are you sure it's really a calibration problem? * Is it always off by
about 5 deg at all temps?

Why not set to where you are comfortable or 5 up- Hide quoted text -

- Show quoted text -

I think it depends on which way it's off. * If it reads 105, but it's
actually 100, then that could be a problem. *Spas are typically set to
go no higher than somewhere around 105. *If you want to get that last
5 deg out of it, you wouldn't be able to. * I like mine somewhere
around 104.

If it's off the other way, or he can live with whatever the incorrect
max turns out to be, then I agree, probably easiest thing to do is
live with it.- Hide quoted text -

- Show quoted text -

The differential is always the same, and the reading is off in the bad
direction. *The controls allow settings only up to 106, which means I
can't heat above 101 actual water temp. *Nice, but not best. *I won't
say I can't live with it, but in the wintertime warmer would be a lot
better.- Hide quoted text -

- Show quoted text -

If you decide you can't live with it, there are a few possible
solutions:

1 - You can call up the manufacturer or local dealer and see what they
say. It's possible they have the info available or can adjust it with
a service call.

2 - It's possible changing the temp sensor would fix it, as that could
be the part that is off.

3 - You could disconnect the wires to the temp sensor. Then use a VOM
to measure it's resistance at a couple of temps and see how it
changes. From that you may be able to figure out how to put an
addional small resistor in series to trick it out by 5 degrees. This
depends on whether the resistance goes up or down with temp, not sure
which it does

4 - You could open up the power pack. You'll likely find 2 or 3
potetiometers inside. One of them likely makes the adjustment you
want. Carefully keep track of what you're doing and change one a 1/2
turn at a time and see what happens, until you find the right one.
That's what I wound up doing on my old NEMCO when I ran into a similar
problem. If you do that, keep in mind that you may see the display
change even when you're not on the pot that really adjusts what you
want. For example, there might be one that fiddles with the
linearity over the temp range, or similar that will cause the display
to read differently when you screw with it. I think mine had 3 pots.