Pool Heater Broke Following Lightning Event

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Usnavy1610

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Aug 27, 2018
18
Georgetown, TX
Hello,



I had a recent near-field lightning event that caused electrical damage to multiple things in my house, including my Mastertemp 400 (MT400) heater ((controlled by a Pentair EasyTouch control panel) which is not working properly. Symptoms and troubleshooting:

  1. With power applied to EasyTouch panel and the main pump off, everything appears normal. MT400 heater is off, no lights on (at least that's my recollection of how it should be).
  2. When I turn on just the main pump (Spa Heat Mode is off), the MT400 blower immediately turns on and stays on. Thus, power is being applied to the MT400 from the EasyTouch. However, the MT400 touch panel is entirely dark (no lights), and the backside of the control panel is dark, too. Additionally, the Ignition Control Module is entirely dark.
  3. When I turn on the Spa function via the EasyTouch, the main pump and MT400 blower both turn off as the two valves that redirect water to and from rotate to support the Spa function. If I recall correctly, the pump and MT400 turning off during this transition is normal behavior.
  4. Once the valves are in the correct position for Spa, the main pump turns back as normal, and so does the MT400 blower. However, not unexpectedly, with the heat temperature set above ambient temp, the unit does not ignite but the blower keeps smelling. No propane odor noted.
  5. Although there are no lights on the control board, I verified that 24VAC (27VAC specifically) exists on both main connectors, and there is 27VAC on the Ignition Control Module as well. Given the absence of any error lights, I confirmed with a multimeter that PS, HLS, ES1, AFS, AGS, GAS sensors were all closed/shorted, while the SFS is open. I believe that these are correct behavior for these sensors.
Given these symptoms, and that 24VAC is applied to the control board but no lights whatsoever, I’m led to believe that the control board at a minimum is bad. Before I go off and start buying things, I wanted to ask this team if there is anything else I should check. For example, could the ignition control module be bad and result in no lights on the control board, and how could I verify that? Any help appreciated. Thanks, Stu
 
Your main board on the mastertemp is most likely gone. As well as the keypad. Mastertemps are the absolute worst heater made. Keep your chems in perfect balance or the exchanger will turn your pool into a copper stain party. I person hate these heaters. You should have a com wire running from the heaters fireman's switch to heater terminal behind the automation panel. If you are getting 24 volts on this line at the heater but the heater is not engaged on the panel (calling for heat) the motherboard on the automation panel could also have gone bad. Also there is a small glass fuse inside the heater where the com wire and fireman's switch is. Make sure it's ok. Best of luck. Wait till the rodents start eating your wiring inside the heater. Worst design ever. I sell a lot of pentair equipment but will recommend a Hayward gas heater anyday over the master temps.
 
Thanks for the feedback. First, correction on my original post. #4 should say "the unit does not ignite but the blower keeps BLOWING."

@JamesW- photo of box w/ ICM is attached. Any feedback appreciated. I will check out the link you sent.
@Srqpoolguy- From photo, fuse looks like it's not blown, but I will verify in the morning and also check on for voltage on control line coming from the EasyTouc. Just to confirm, if EasyTouch is not calling for heat, line should be 0V. Calling for heat, 24V. Is that VAC or VDC for that line?

I'm hoping that there is nothing bad with the EasyTouch control panel- the rest of the pool automation is working correctly.

Thanks SRM
 

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Usnavy1610 said:
. Just to confirm, if EasyTouch is not calling for heat, line should be 0V. Calling for heat, 24V. Is that VAC or VDC for that line?
Click to expand...

The fireman’s switch line always has 24V supplied by the MasterTemp. All the EasyTouch does when it wants heat is close a relay which completes the 24V power in the heater powering the controls.

The lightning strike may have welded the relay contacts closed so the heater is always on.

If the lightning strike hit the fireman’s switch line it could have taken out the heater relay in the EasyTouch board and some of the control electronics on the MasterTemp board.

The heater blower would not be running without some electronics belng powered by the 24V into the PCB and Fenwal.

The blower is the first thing to begin running in the heater start sequence after the PCB a is powered.
 
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Thanks for your replies.

@JamesW: I will try a jumper tomorrow morning.
@ajw22: Thanks for the clarification on the control line.

In summary, remove the control lines inside the box. Apply the jumper and see if the MT400 symptoms stay the same. If they do, issue is likely the control board and possibly the ICM?
To rule out an EasyTouch control issue, while control line is disconnected, measure continuity across the two wires. I should have a short when EasyTouch calls for heat, open when not.

SRM
 
Usnavy1610 said:
.In summary, remove the control lines inside the box. Apply the jumper and see if the MT400 symptoms stay the same. If they do, issue is likely the control board and possibly the ICM?
Click to expand...

Jumping the fireman’s switch connection in the heater puts the heater back under control of its control pad. See how it behaves.

Usnavy1610 said:
To rule out an EasyTouch control issue, while control line is disconnected, measure continuity across the two wires. I should have a short when EasyTouch calls for heat, open when not.
Click to expand...

Correct.
 

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Thank you again for your feedback and guidance. Quick update:
- Disconnected control wire from EasyTouch and jumpered Fireman’s Switch. Turned on breakers, everything stays off as configured. Turn on main pool pump, 240VAC power is immediately applied to MT400 and blower turns on immediately and stays on as long as main pump is on, even when I’m not in Spa mode (same as before). The MT400 keypad does work (SPA ON, POOL ON, HEATER OFF, TEMP UP/DOWN). With desired temp set well above ambient, “Heating” light does turn yellow, but heating never turns on and ultimately “Service Heater“ comes on. Rear Control board goes through a series of typical various flashes, but always ends of on LED 9 or 10 (Pool or SPA) GREEN, and LED 11 (Service) RED. All the other error lights are off.
- With the EasyTouch control wires disconnected, I measured continuity across them. They always stayed open, even when EasyTouch Spa was on and I set the heat temperature several degrees above ambient (the red flame would show on my ScreenLogic app). Is it possible the relay in the EasyTouch needs to see the 24VAC in order to close the circuit?

Any thoughts appreciated.

SRM
 
Possibly a defective circuit board.

Hard to tell for sure.

You might have several different defective parts, which makes the diagnosis especially difficult.

How old is the heater?
 
You might need to get someone onsite who can check everything.

If you have multiple defective parts, it is very difficult to figure out which parts are bad.

The problem is that it is probably not worthwhile spending a lot on service calls and parts for a heater that is almost 10 years old.

Maybe pull the circuit board and check for any obvious damage.

It might be a defective Fenwal Ignition Controller, but they are expensive and you don't want to replace it unless you are sure that it is definitely bad and that there are no other bad parts.
 
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Usnavy1610 said:
Turn on main pool pump, 240VAC power is immediately applied to MT400 and blower turns on immediately and stays on as long as main pump is on, even when I’m not in Spa mode (same as before). The MT400 keypad does work (SPA ON, POOL ON, HEATER OFF, TEMP UP/DOWN).
Click to expand...
Typically, you want the heater powered all the time and not based on the filter pump relay.

The heater should be allowed to cool down if the pump is turned off.

The fan should run for about a minute if the pump turns off.

If the heater is trying to fire and it does not fire and it says Service Heater with no error LEDs, then that is usually a flame sensing issue and this should cause the red LED on the Fenwal Ignition Controller to blink in one of the patterns indicated on the controller.

You might have a bad igniter or a bad gas valve.

Check for 24 VAC at the gas valve and check for 120 volts at the ignitor during call for heat.

Check the amperage going to the ignitor.

Check the resistance of the ignitor.
 

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