MasterTemp 300

[JamesW]

You can see the internal bypass by looking in the inlet to see the spring and you can see the plunger disc by looking in the hole where the thermal regulator goes.

The disc is on the top of the wall.

Check the internal bypass by looking into the hole where the thermal regulator goes and into the heater inlet to see the spring.

 

[JamesW]

A is the Inlet.

B is the Thermal Regulator access.

If you look into the Inlet (A), you should be able to see the spring part of the Internal Bypass.

If you look into the hole for the Thermal regulator (Up and to the right), you should see a black disc (Arrow).

 

[rookies]

Check the internal bypass by looking into the hole where the thermal regulator goes and into the heater inlet to see the spring.

View attachment 617320View attachment 617319

James, the thermal reg was stuck closed and the disc was not sitting flush, it was sticking out approx 1/2 inch...I assume part of my problems....I could not unscrew the cap to get to the thermal reg...but took the manifold apart to view everything...

 

[rookies]

James, the thermal reg was stuck closed and the disc was not sitting flush, it was sticking out approx 1/2 inch...I assume part of my problems....I could not unscrew the cap to get to the thermal reg...but took the manifold apart to view everything...

James....Replaced the cracked manifold, it came with new thermistor, HLS, water pressure switch, gas shut off...Also added new thermal reg that was stuck closed.

Heater panel still runs 12 degrees higher than the easy touch and screen logic app....heater used to shut off at 85 deg, it now stays on til 101 deg. Easy touch is approx 90 deg when heater shuts off.

Too dark right now to check anything, tomorrow I will check the stack flue.....any clue why the heater panel is 12 deg higher then easy touch....water appears to be accurate with easy touch, not the heater panel...

Thanks
Troy

 

[rookies]

James....Replaced the cracked manifold, it came with new thermistor, HLS, water pressure switch, gas shut off...Also added new thermal reg that was stuck closed.

Heater panel still runs 12 degrees higher than the easy touch and screen logic app....heater used to shut off at 85 deg, it now stays on til 101 deg. Easy touch is approx 90 deg when heater shuts off.

Too dark right now to check anything, tomorrow I will check the stack flue.....any clue why the heater panel is 12 deg higher then easy touch....water appears to be accurate with easy touch, not the heater panel...

Thanks
Troy

Also...no red LED lites, and no error codes, no service....everything looks good but just reads 12 degrees too high...

 

[JamesW]

Is it accurate when the heater is off?

Maybe the board is going bad.

Try using a 10k resistor connected to the thermistor terminals to see if the heater reads at 77 degrees.

Only do this with the heater off and not while the heater is running.

 

[rookies]

Is it accurate when the heater is off?

Maybe the board is going bad.

Try using a 10k resistor connected to the thermistor terminals to see if the heater reads at 77 degrees.

Only do this with the heater off and not while the heater is running.

When heater is off, easy touch temp is accurate...Im not sure what a 10k resistor is...

 

[JamesW]

I'm not sure what a 10k resistor is.

It is a resistor with 10,000 ohms of resistance.

Wire it like it was the thermistor (Temperature Sensor).

Welcome to TFP.

When the pump is running the display should show the water temperature and only show the set temperature for a few seconds after you press the up or down arrow.

You could have a bad thermistor temperature sensor. The heater is not going to turn on if it thinks the water temp is equal to your set point temp.

You could also have a bad keypad.

Or the main board could be bad.

The easiest and least expensive check is to put a 10K resistor in place of the thermistor. It should read 76 degrees +/- 1 degree. If it reads correctly with the 10K resistor in place then your main board is good and you need to replace the thermistor.

Only install the 10K resistor as a test.

Below are pic of doing the 10K resistor test on my Pentair MasterTemp which is internally identical to your Sta-Rite heater. I used some nails and alligator clips to connect the 10K resistor to the connectors.

You can also use a multimeter to check the resistance of the thermistor to determine what water temperature it is reading. See Temperature Sensors - Further Reading

 

[JamesW]

When heater is off, easy touch temp is accurate

Is the heater display temperature accurate before the heater runs and once the heater fires up?

 

[ajw22]

 

[rookies]

Is the heater display temperature accurate before the heater runs and once the heater fires up?

James, when the heater first turns on, it is accurate...like right now it would show in the 50's then build heat til the set point. But if the set point is 100 deg and shuts the heater off, easy touch is only approx 90 deg...

 

[ajw22]

But if the set point is 100 deg and shuts the heater off, easy touch is only approx 90 deg...

Test the pool/spa water temperature using a good food thermometer. Is it 100 degrees or 90 degrees?

The EasyTouch and the MasterTemp have independent temperature sensors. We need to know if you should be looking for the problem in the heater or the EasyTouch system.

 

[JamesW]

Possibly a bad board, bad sensor or maybe a flow issue where heat is backing up into the inlet due to a flow problem.

Check the board with a 10K resistor.

Check the thermistor with a ohmmeter.

Maybe low flow.

Can you show pictures of the system?

 

[rookies]

Ajw...thanks for the pics, I will get some of these...but sorry, a lil confused...where exactly does the resistor go? Does it go into the female wire connectors that would normally plug into the thermistor? Okay, I looked at the earlier pics...so place a nail into the two female connections that would normally hook up to the thermistor, then let the resistor make contact with the two nails....and if all is good, the heater panel should register 78 deg?
Thanks!

 

[ajw22]

Ajw...thanks for the pics, I will get some of these...but sorry, a lil confused...where exactly does the resistor go? Does it go into the female wire connectors that would normally plug into the thermistor?

Correct.

Okay, I looked at the earlier pics...so place a nail into the two female connections that would normally hook up to the thermistor, then let the resistor make contact with the two nails....and if all is good, the heater panel should register 78 deg?

76 degrees.

Unless you have four hands or helpers to hold the connections together you need to MacGyver some connection of clips to hold the wires onto the resistor.

 

[ajw22]

When you get those 10K resistors connect one in place of the water temperature sensor to your EasyTouch Board and see if the EasyTouch reads 76F for the water temperature.

We need to figure out which device is reading the water temperature incorrectly.

 

[JamesW]

 

[rookies]

Ok Guys....really appreciate the help, as you can tell, Im just a home owner that likes to figure things out with the help of you guys!

I should have thought of this myself...my mistake....

The spa temp is 69 deg, when I turn on heater and it runs a minute or so, it shows real close to 69 deg...easytouch shows 50's ....So, I guess my MasterTemp is accurate and easytouch sensor needs replacing....correct? This is the sensor that sits in the inlet hole to heater...correct?

Ive bought cheap ones over the years off amazon and seems they dont last long...might have to get a Pentair sensor.

I still feel like the spa temp is still too low when it shuts off at 101 at the panel...doesnt seem as hot as it used to be...

 

[ajw22]

This is your water temperature sensor. It looks like it has sealant around it that may be affecting it. Properly installed it should not need sealant.

I still feel like the spa temp is still too low when it shuts off at 101 at the panel...doesnt seem as hot as it used to be...

Measure the actual spa water temperature using a food thermometer.

 

[rookies]

This is your water temperature sensor. It looks like it has sealant around it that may be affecting it. Properly installed it should not need sealant.


View attachment 617772


Measure the actual spa water temperature using a food thermometer.

I did measure with food gauge, spa and heater panel are very close....The white you see is area that had to be grinded down some so the temp sensor would sit flush on pipe....The 90 was too close to the sensor hole....Thanks!