Pentair Master Temp 250 time to replace?

[jobybett]

Hi,

Went to turn on the spa last night (first time in about 4 months) and the heater won't heat. I see the 128 R=8 on the panel, the fan kicks in as usual, but no heat. After about 1 min the service light comes on, and that's that.

The heater is 9 years old, we moved into this house a year ago, so have no idea of its service or usage history. Last summer we did not use it to heat the 22k IG pool, just the IG spa, as and when we wanted to use it.

So my question, should I spend some $$ on getting someone to look at it, or at 9 years should I call it quits and look at a new unit? I'm not a fan on spending money on something that's gonna need replacing soon anyway, I know without looking at it, it's an impossible question, but is it likely I could get 2 or 3 more years out of it?

 

[JamesW]

Check whether any of the red diagnostic LED’s on back of board (AGS, AFS, SFS, HLS or PS) are on.

Are there any error codes?

I suspect that it's going to be a an air flow switch issue or an igniter issue.

Do you smell gas during the startup attempt?

 

[jobybett]

Check whether any of the red diagnostic LED’s on back of board (AGS, AFS, SFS, HLS or PS) are on.

Are there any error codes?

I suspect that it's going to be a an air flow switch issue or an igniter issue.

Do you smell gas during the startup attempt?

Nope no smell of gas, looks like the AGS led is on

 

[ps0303]

Sounds like it is erroring out before it tries any of the real startup processing.

The AGS sensor is on the right side of the header. It is the side where only one sensor is located. Now that error LED can be a trick as well. I have seen bad boards throw that error out. You can try to bypass that sensor with a jumper wire and see what happens.

 

[JamesW]

You can test the AGS with a multimeter. If it shows open, then it's bad.

 

[jobybett]

Assuming this is the right sensor, yes it’s open

 

[JamesW]

Yes, just replace the AGS switch.

 

[jobybett]

Thanks for the help guys!!

Last question, would you stick with a 250 or go up to a 300 or 350? Given it’s really only used to heat an IG spar that’s about 6’ diameter and 4’ deep

 

[mknauss]

I believe you only need to replace the sensor ------

 

[JamesW]

250 should be good for a spa. If you wanted to upsize, you would have to make sure that the gas line and meter are big enough.

All you should need now is the AGS switch.

You can temporarily connect the two wires together that go to the switch to see if the heater fires. Don't leave them connected.

Make sure that you have good flow and only let the heater run for a few seconds.

Don't run the heater with a bypassed switch for normal operation.

 

[jobybett]

Ok so I secretly wanted a new one, but you are 100% right, bypassed the sensor and she fired up perfectly hot air coming out of the exhaust. Only ran it a few seconds, as you said.

Thanks so much!! I’ll replace the sensor and see how long I can keep it going.

Thanks again guys!!!

 

[JamesW]

Cool. Good job.

 

[Pool Clown]

Thanks for the help guys!!

Last question, would you stick with a 250 or go up to a 300 or 350? Given it’s really only used to heat an IG spar that’s about 6’ diameter and 4’ deep

Upgrading is going to give you quicker heat up times and a bit of gas savings (you may, or may not notice on your gas bill). And as stated earlier, you would need the appropriate size gas line for the increased gas requirement.

 

[jobybett]

Thanks PC, I think I will upsize a little when the time comes.

New AGS comes tomorrow, is there anything special I need to know about replacing it? Or is it just as simple as it looks? Wires off, unscrew, screw in wires on....

 

[JamesW]

That's about all there is to it. Turn off the pump and remove the heater drain plug.

The AGS comes with Teflon tape on the threads but you might want to put a few extra wraps for a good seal. It should go in snug but don't over tighten.

Reinstall the drain plug and start the pump.

Wait a few minutes then start the heater.

 

[jobybett]

Again big thanks guys!! New AGS is in and its working great!!

On a side note, while the side was open I found a nice critter nest in there (Rat, squirrel, something else) so cleaned it all out, there is a bit of gnawing on wires, but noting serious, hahaha

 

[JamesW]

Good job.