MasterTemp 400 won't stay lit

[Variant]

Troubleshooting my MasterTemp 400. Kicks on, calls for heat, ignites (I can feel hot air coming out of the exhaust) but after 30 seconds or so the igniter goes off and the AGS light trips.

I don't get any continuity on the AGS switch itself so thinking that's the problem, but then why would the system ignite once at all? I've also cleaned the igniter but not replaced it.

I'm thinking I could jump the AGS wires and see if the system stays on to rule out the igniter and control board?

(I've also just replaced the flue sensor and pressure switch and those lights no longer trip.)

 

[ajw22]

Read Pentair MasterTemp Heaters - Further Reading

Check the internal bypass valve.

 

[1poolman1]

Troubleshooting my MasterTemp 400. Kicks on, calls for heat, ignites (I can feel hot air coming out of the exhaust) but after 30 seconds or so the igniter goes off and the AGS light trips.

I don't get any continuity on the AGS switch itself so thinking that's the problem, but then why would the system ignite once at all? I've also cleaned the igniter but not replaced it.

I'm thinking I could jump the AGS wires and see if the system stays on to rule out the igniter and control board?

(I've also just replaced the flue sensor and pressure switch and those lights no longer trip.)

Are you hearing any noises just before the heater shuts off? Checked water flow?

 

[Variant]

Thanks, everyone. Flow and internal bypass look good and turns out it's not the AGS. Probably control board at this point as it's maybe the only thing not yet checked.

 

[Poolbreh]

Your feed says you got a new vsp, make sure flow is adequate 40gpm.

 

[Variant]

Ok, thank you Poolbreh!

 

[Variant]

Hi everyone. Update:

Got a new control board in after having a pro come out and verify everything else. He thought it was the control board but recommended I order online since it was less than half the price of his. Received and installed tonight but board doesn't seem to be getting any power at all. And when I put the old board back, it no longer seems to get power either (no lights on front or back of the board).

I tried testing AC voltage across pins 3 & 4 of the set of wires that I think comes from the transformer but get nothing but may not have gotten a good contact through the molex like connector.

Here's the board I ordered.

Happy to post pics of how I wired things up.

 

[Poolbreh]

You need to verify voltage coming into heater, make sure fireman switch loop is closed, make sure fireman fuse is good. Did you install it with the power off?

 

[Variant]

You need to verify voltage coming into heater, make sure fireman switch loop is closed, make sure fireman fuse is good. Did you install it with the power off?

Yep, did install w/ power off, but will check fuse all the same.

 

[Variant]

Update on this.

Fuse was indeed blown, but turned out the control board I bought was either bad or incompatible (guess it was after market). Am returning it.

Pro came out and verified everything else looks fine, including gas and water flow.

Ordered a new board:

Pentair StaRite 461105 Heater Control Board - PoolSupply4Less

Pentair StaRite 461105 replaces the 42002-0007S Control Board Kit. Fits Max-E-Therm and MasterTemp Heaters. Factory oem replacement board

www.poolsupply4less.com

Installed and heater kicks on, stays on and is heating, but I'm not seeing any digits on the control board LCD display, only the backlight. I verified the 3-wire jumper is across pins 1 & 2. I can turn the heater off and on with the Pool/spa and Heater off button just fine.

The kit did come with a red/black cable that I didn't find a place for.

Suggestions?

 

[JamesW]

The kit did come with a red/black cable that I didn't find a place for.

 

[Variant]

Alright, will give this a shot. Thanks!

PS: The temperature buttons also still seem to work and call for more heat, just can't tell what the setting is. Hopefully this wire does the trick...

 

[generessler]

Sounds like you're on the way to a fix, but will point out I had a similar-sounding problem that was correctly diagnosed by folks here as a Fenwal flame sense/grounding issue. Pentair sells a fix kit for it, which is just a piece of wire (for $16!). But before trying that I just carefully slightly loosened and re-tightened hardware in the igniter area. The problem went away Has been okay for two years so far, knock on wood.

 

[ajw22]

The red/black cable only connects to the new model Fenwal that is on the "connected heater". If you have the old model MasterTemp heater there will not be a connection on the Fenwal for the diagnostic digital data.

Check the seating of the keypad connector on the board. Or you got a bad keypad with your new board.

 

[JamesW]

I verified the 3-wire jumper is across pins 1 & 2.

Are you talking about JMP1?

How are you controlling the heater?

 

[JamesW]

If you are not using a 3-wire control, you want the jumper in the top position.

You can control the heater from the heater control panel, from a fireman's switch, a 3-wire or RS485.

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/mastertemp/manual/Manual-MasterTemp-472592-English.pdf

 

[JamesW]

How old is the heater?

What is the part number and date from the label with the barcode?

Can you show a picture of the Fenwal ICM (Ignition Control Module)?

Do you have automation like EasyTouch, IntelliTouch or IntelliCenter?

 

[JamesW]

 

[JamesW]

The keypad is the 6 button keypad, so it should be the new heater.

Is the keypad original?

 

[JamesW]

These are the part numbers for the Mastertemp 400 models.