- Jun 14, 2022
- 46
- Pool Size
- 25000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Autopilot Digital PPC3 (RC-42)
Just opened up for the season this week, and diagnosing a heater problem. It's a Max-E-Therm 400 NG heater, about 7 years old. New igniter was installed last year. Controlled by IntelliCenter ("IC") via Fireman's Switch, and running on 120v. Heater panel is set to max temp (104F). IC is set for 70F; current water temp is 55F (agreed by both IC sensor and heater).
When I turn heat on at IC, the heater goes through normal startup, and ignites as normal. LED8 ("heating") stays on. After anywhere from 2-5 minutes, the flame cuts off, LED8 goes into "heat demand" mode (flashing continuously). About 30 seconds later, it reignites, LED8 goes solid, but will only run for less than a minute. The cycles continue this way for at least four cycles (as long as I've let it go thus far). Behavior is the same after I shut off heat, give it a rest and start over calling for heat (i.e., initial multi-minute run, followed by half-minute cycles).
There are no diagnostic lights at any point on the control board nor on the Fenwal ICM. The Service light never comes on, nor any of the specific sensor fault indicators. The ICM does not go into lockout, as it appears it is happy with each ignition. There is definitely air flow through the blower (I can feel the suction when I bring my hand to cover the intake). Tubes to the AFS seem to be clear. Heating canister seems to be intact (I can see no heavy corrosion areas at least in what's visible).
Any thoughts on the likely faults here? Is it likely that the igniter loses flame sense and shuts down (if so, would there be a diagnostic at the ICM or control board)? I haven't pulled the igniter yet for a visual, but as I mentioned above, it's quite new. I wonder if the shortened cycles after the initial one are due to the fact that the igniter is more fully heated from the first on cycle?
When I turn heat on at IC, the heater goes through normal startup, and ignites as normal. LED8 ("heating") stays on. After anywhere from 2-5 minutes, the flame cuts off, LED8 goes into "heat demand" mode (flashing continuously). About 30 seconds later, it reignites, LED8 goes solid, but will only run for less than a minute. The cycles continue this way for at least four cycles (as long as I've let it go thus far). Behavior is the same after I shut off heat, give it a rest and start over calling for heat (i.e., initial multi-minute run, followed by half-minute cycles).
There are no diagnostic lights at any point on the control board nor on the Fenwal ICM. The Service light never comes on, nor any of the specific sensor fault indicators. The ICM does not go into lockout, as it appears it is happy with each ignition. There is definitely air flow through the blower (I can feel the suction when I bring my hand to cover the intake). Tubes to the AFS seem to be clear. Heating canister seems to be intact (I can see no heavy corrosion areas at least in what's visible).
Any thoughts on the likely faults here? Is it likely that the igniter loses flame sense and shuts down (if so, would there be a diagnostic at the ICM or control board)? I haven't pulled the igniter yet for a visual, but as I mentioned above, it's quite new. I wonder if the shortened cycles after the initial one are due to the fact that the igniter is more fully heated from the first on cycle?