Mastertemp 400 humming (already replaced the "run" cap) still humming

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tirolocop

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Jan 5, 2014
9
Hi my tfp friends

I have a Mastertemp 400 and its blower humm when pool or spa are turned on (humms like a pump motor with a failed cap), and "service heater" led turns on, i already replaced the cap (8uF-250vac), but still the same failure.

Problem starts when working (last weekeend) there was a global electric failure on my block, after that, all works well (pumps, spa blower, cloerine and acid supplier, etc) except the heater.

Theres no error at display (until i press pool or spa the "service heater" led turn on)

The heater blower spin manually without any issues, what could be?

heres a video:

Thank you!

PD gas and water flow are ok
 
Check the incoming power supply to make sure that it's correct.

Check that the voltage going to the motor is correct.

You can power the motor directly to see if it works.

As soon as the On button is pushed, the Service Heater light comes on.

Usually, there's a slight delay. So, it might be a bad circuit board or ignition control module.
 
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The display shows 25, which is 77 Fahrenheit. Did the heater get changed to metric?
To toggle the display between degrees Centigrade (°C) and degrees Fahrenheit (°F):
1. Turn the Operating Control OFF.
2. Press ^TEMP or down TEMP for 5 seconds. The display will flash once and change modes (°C to °F or vice versa).
3. Turn the Operating Control ON.
When either the ^TEMP or down TEMP buttons are depressed, the digital display will indicate the temperature setting.
After five seconds, the display will return to the actual pool/spa temperature.

If you didn't intentionally change it, it might indicate a power surge happened.

Check the circuit board for damage.
 
Disconnect the IND wire from the ignition control module and check the wire for 24 VAC.

If no voltage, check pin 3 of the J1 terminal for 24 VAC.

If no voltage at pin 3 of J1, check voltage at pin 6 of the J2 terminal.

Check for 120 VAC at the F2 terminal of the ignition control module.
 
Should also check the actual micro farads on the capacitor with a meter. Have had brand new just installed furnaces with a bad brand new capacitor from the factory. They don't make the capacitors in the US anymore and quality control is not what it used to be,
 

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Because of the reason for the outage, or if there was an issue when restoring power, some appliances have trouble dealing with voltage spikes sometimes associated with both the de-energizing and re-energizing of the system. Some examples of damage before loss of power could be things like a car hitting a pole or a lightning strike. Ideally, you get protection from these types of issues and your interruption occurs without incident. An example of re-energizing problems could be a replacement of a fuseable link on a power pole that didn't go smoothly, and took more than one try to get it installed.

Your proximity to the event also has some bearing on what you receive before you get the interruption.

Now, if this were the case, your heater blower could have received a damaging voltage spike. The only component on that heater that gets constant voltage (hot all the time) is one leg of the blower. I would guess a damaged blower. Not being there to see the heater in person, this would be my thoughts given the information that you provided. I am a dealer and would not be able to shed any light on rebuilding the blower, or if its possible. I dont even replace caps on that motor. The thinking is, New cap, same old motor (age of bearings, armature, etc.).

Like James suggests in post #6, power the blower motor directly, and go from there.
 
Last edited:
The blower has 3 sets of windings. 2 main run windings and an auxiliary start winding.

Red and blue go to one set of windings. Black and yellow go to the other set.

For 120 volts, the windings are in parallel. For 240 volts, the windings are in series.

The auxiliary start winding is in parallel with the black --> yellow winding.

Remove the capacitor and test for resistance from red to blue and black to yellow. The values should be the same.

Label the capacitor wires C1 and C2. Test from C1 to C2, C1 to black, C1 to yellow and C1 to white.

Test from C2 to black, C2 to yellow and C2 to white.

Test from each wire to the green ground wire to see if any wires are shorted to ground.
 
To test the motor directly wire as follows:

For 240 volts, Black to hot leg, Red to the other hot leg, blue and yellow connected together.

For 120 volts, red and yellow to one line, black to the other line and blue and white connected together.

Note: I think that this is right, but I can't guarantee it. It's presented as is. If you want to test like this, you do it at your own risk.

Do the resistance test first as that should tell us something.

Test the capacitance of the capacitor to make sure that it's correct.

One power leg is always connected to the blower motor and the black wire from F2 is the switched leg.

You might have gotten a power surge, but I don't know if it would affect the motor if the switched leg was not connected because the current could not flow.

I suspect that it's a board or ignition control module problem.

Either way, the recommended tests should let us know something.
 
Last edited:
JamesW said:
The blower has 3 sets of windings. 2 main run windings and an auxiliary start winding.

Red and blue go to one set of windings. Black and yellow go to the other set.

For 120 volts, the windings are in parallel. For 240 volts, the windings are in series.

The auxiliary start winding is in parallel with the black --> yellow winding.

Remove the capacitor and test for resistance from red to blue and black to yellow. The values should be the same.

Label the capacitor wires C1 and C2. Test from C1 to C2, C1 to black, C1 to yellow and C1 to white.

Test from C2 to black, C2 to yellow and C2 to white.

Test from each wire to the green ground wire to see if any wires are shorted to ground.
Click to expand...

Thank you all for your tips,

here are the tests

-----------------------
BK to Y = 11.6 ohms
R to BL = 11.7 ohms
-----------------------
C1 to BK = 26.4 ohms
C1 to Y = 38.0 ohms
C1 to W = 26.4 ohms
-----------------------
C2 to BK = 11.7 ohms
C2 to Y = 0.0 ohms
C2 to W = 11.6 ohms
-----------------------
C1 to C2 = 38.2 ohms
-----------------------
Continuity:
G to any (BK, Y, W, R, BL, W) = none
-----------------------
Cap = 8.3uF
-----------------------

is the motor ok?

thank you in advanced

PD its configuration its at 220v
 
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Based on the tests, it appears that the motor is ok.

I would do the power test to see if it runs.

I'm pretty sure that the power test that I described is accurate, but I can't 100% guarantee it.

The white wire is connected to the black wire, so cap it off when applying power to the black wire so that it doesn't make contact with anything.

If the power test shows that the motor is good, the problem is likely to be with the ignition control module or the main board.

There are some other tests described in earlier posts that might be helpful.
 
You can check the power going to the blower.

When the heater tries to start, you should be seeing 240 volts from red to black on the wires going to the blower.

You can disconnect the blower plug and test the power at the red and black wires.

Have the meter connected because the power might shut off after a few seconds.

The red should be powered any time the heater is powered.

So, you should get 120 volts on that leg before the heater tries to start.

The black wire doesn't get power until the blower is supposed to be on. When the heater tries to start, power is applied to black and you should get 240 from red to black.
 
Last edited:
JamesW said:
Based on the tests, it appears that the motor is ok.

I would do the power test to see if it runs.

I'm pretty sure that the power test that I described is accurate, but I can't 100% guarantee it.

The white wire is connected to the black wire, so cap it off when applying power to the black wire so that it doesn't make contact with anything.

If the power test shows that the motor is good, the problem is likely to be with the ignition control module or the main board.

There are some other tests described in earlier posts that might be helpful.
Click to expand...

".... for 240 volts, Black to hot leg, Red to the other hot leg, blue and yellow connected together"

i understand that, but i did not about the white wire

can you be more specific, also, capacitor stays connected right?
 
You can do it with 120 volts or 240 volts as I described. The capacitor stays connected.

You don't have to do anything with the white wire, just don't let it make contact with anything because it will be energized during the test.
 
JamesW said:
You can check the power going to the blower.

When the heater tries to start, you should be seeing 240 volts from red to black on the wires going to the blower.

You can disconnect the blower plug and test the power at the red and black wires.

Have the meter connected because the power might shut off after a few seconds.

The red should be powered any time the heater is powered.

So, you should get 120 volts on that leg before the heater tries to start.

The black wire doesn't get power until the blower is supposed to be on. When the heater tries to start, power is applied to black and you should get 240 from red to black.
Click to expand...

Test result:
Heater connected (SPA/POOL OFF):
BK to G = 129v
R to G = 132v
BK to R = 0.35v

Heater connected (SPA/POOL ON):
BK to R = 242v

Later with help of the mother of my daugher =), i will test the blower directlty (240v)
BK to L1
R to L2
BL and Y with a jumper
right?

Also with the blowere disconnected, if i turn on SPA/POOL, no SERVICE LED is turning on
 
tirolocop said:
Heater connected (SPA/POOL OFF):
BK to G = 129v
R to G = 132v
BK to R = 0.35v
Click to expand...
Is this with the blower connected or disconnected?

tirolocop said:
BK to L1
R to L2
BL and Y with a jumper
right?
Click to expand...
I believe that this is accurate.

Also, remove and inspect the voltage selector plug to make sure that it's not damaged.

Note: No guarantees on anything. Only do what you know that you can do safely. Do at your own risk.
 

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