Mastertemp 400 not firing

No continuity, with no call for heat. Appears to be functional. Let me ask this. On my old heater board, I could control the on/off and move the temp up/down with the ET. With this new board, the ET can control the on/off, but has no control in setting the temp. Is this how it’s supposed to be? Just trying to clarify
 
No continuity, with no call for heat. Appears to be functional.

When you remove the two orange wires on your heater does your heater run?

img_7571-jpg.484871

Let me ask this. On my old heater board, I could control the on/off and move the temp up/down with the ET.

The heater should be set in SPA mode with its temperature on the heater control panel set to 104. And you leave it there.

All temperature control comes from the EasyTouch.

With this new board, the ET can control the on/off, but has no control in setting the temp. Is this how it’s supposed to be?

The new heater works the same.

When you say "has no control in setting the temp" is that on the ET or the MasterTemp? Where is there no control?
 
When you remove the two orange wires on your heater does your heater run?
No, heater won’t run with them disconnected. Presumably because the fireman’s switch has to be jumpered by some method, in order to run.

When you say "has no control in setting the temp" is that on the ET or the MasterTemp? Where is there no control?
I now see that the heater does shut off when it reaches the set temp from the ET. The display and presentation is just different than what I had with the old board . I was confusing the set point of the heater display as the controlling value (as pictured=>104). The numbers don’t exactly match up, but that’s not a big deal. As pictured, the spa is heating. It stopped when the remote displayed 88/87.

So the heater will stay in spa mode, but why did they give a pool mode, if it’s never to be used?
 

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No, heater won’t run with them disconnected. Presumably because the fireman’s switch has to be jumpered by some method, in order to run.

Yup, that is what your ET does with closing the heater relay.

I now see that the heater does shut off when it reaches the set temp from the ET. The display and presentation is just different than what I had with the old board . I was confusing the set point of the heater display as the controlling value (as pictured=>104). The numbers don’t exactly match up, but that’s not a big deal. As pictured, the spa is heating. It stopped when the remote displayed 88/87.

The ET water temperature and the Mastertemp water temperature come from two different sensors in different locations. Being off by a degree of two is common.

So the heater will stay in spa mode, but why did they give a pool mode, if it’s never to be used?

If you do not have automation and are controlling the MasterTemp from the heater control panel it gives you two temperature settings to switch between with the press of the POOL or SPA button. With automation you want to take the heater thermostat out of the controls by setting it to its 104F maximum.
 
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Bingo!! Makes sense. Thanks AJ for all the help !!! U, me and my son have the exact same initials. AJW😁. Have a great weekend brother.
Next project will be to replace the 12 bolts that attach the manifold to the heater. They are totally rusted out. I will replace the thermal reg and bypass valve while I’m in there. Gonna use stainless steel bolts
 
Bingo!! Makes sense. Thanks AJ for all the help !!! U, me and my son have the exact same initials. AJW😁. Have a great weekend brother.

AJW :goodjob:
Next project will be to replace the 12 bolts that attach the manifold to the heater. They are totally rusted out. I will replace the thermal reg and bypass valve while I’m in there. Gonna use stainless steel bolts

Has your heater been in a flood?

How old is your heater?

Get the O ring kit with 12 O rings and the O ring for the manifold and replace it when you open up the manifold.

I would have though those bolts were SS. We don;t see them rusting often even with leaking heat exchangers.
 
It was installed 2010. No flooding but it is salt water. There seems to be a small bit of water seeping out onto the ground around the manifold too. I’m surprised they are so bad. I don’t think I can even put a socket on some the bolt heads. Will have to grind those down use an easy out.
A few years ago I had to replace the main pump motor because the bearings and motor case completely disintegrated. I also have a waterfall pump and cleaner booster pump. Those are still original. Was baffled by why one would completely fall apart and the other 2 are unaffected. Since then I check the bonding wire much more frequently
 
It was installed 2010.

13 years is a good run for a heater.

There seems to be a small bit of water seeping out onto the ground around the manifold too.

That would make me suspect that you have a leaking heat exchanger.

If you can pull the lower left bolt and see if you get water dripping from the hole.

When you remove the manifold you may find corrosion of the burner can. Once you are in that deep it may be worthwhile opening the burner can and seeing the condition of the heat exchanger. Understand you may not like what you find as you dig into the heater.

Jandy JXI400N - Trouble Air describes how a member diagnosed the problems in his Jandy JXI400 heater, discovered the heat exchanger was leaking, and replaced the heat exchanger. The MasterTemp design is very similar to the JXI.
 
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I had this same issue. Wasn’t getting any error lights on board. I noticed I didn’t smell gas like I did in past years. Figured was gas valve. The light in electrical box was blinking 3 times. (ignition lockout.) I checked all my connections. Found the on off switch wasn’t all the way in on position. Put switch to off then all the way back on. Hit power to pool button on main board started up heard a click smelled gas been running perfect for 2 weeks now. Hopefully something as simple for you.
 
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