Teledyne Lars Series 2 Heater no ignition

[KDpoolguy]

My parents have a 1994 Teledyne Lars Series 2 Heater that’s been in hibernation since COVID struck. Model is ESC250N. It was working 2 years ago, but now when the thermostat (potentiometers) move, I do hear a ‘click’ that it’s recognized temperature, but nothing else and it’s not igniting.

My feeling is to just begin by replacing the ignition module after confirming I’ve got power from the transformer. I’d like to try most things that can be done while I’m at the house for an hour. Their spa isn’t used much, so a service call and repair bill north of a few hundred dollars doesn’t really make sense.

I rebuilt a similar heater, and ultimately it turned out to be a ground issue. The new ignition modules (upgrades from the original Honeywell S8600F) have LEDS that have more basic diagnostics, so I can tell if it’s sending spark. Doe
s anyone have any place to start?

Thanks,
Kevin

 

[JoyfulNoise]

2020 - 1994 = 26 years …

I think it’s time to take the win and call it done. Do you really want to spend time tracking down ghosts and gremlins in the machine just to get a 26 year old heater working that no one will probably use anyway?

Install a new Raypak heater and enjoy the time not wasted on repairs.

 

[KDpoolguy]

I hear ya Matt. I’ve been in this scenario with 2 other heaters now.
My feeling is if it’s a failed exchanger, then ya, it’s a new unit.
These units are so bulletproof, and solid-state and thus more repairable than the new units. If I can get it working, for a reasonable amount, then I feel it can last another 5+ years. If it doesn’t get fixed, I doubt there’s a new unit in the future.

 

[ajw22]

I would start with confirming you have proper gas pressures at the gas valve using a manometer.

If you have good gas then work on if you have good spark.

I don't believe is simply throwing expensive parts in hoping it fixes an unknown problem. Some diagnostics using a multimeter can follow the startup sequence.

You confirm all the safeties are closed?

@swamprat69

 

[KDpoolguy]

I bypassed the safeties and still no spark, so I haven’t individually tested them. Pilot ignition looks fine. No spark passed the gap when I removed the wire.
That’s what’s leading more conclusively to ignition module—and yes it could also be gas valve still.

Is the Honeywell S8610U the best replacement for the original s8600? If it’s not, I can package it up and return it.

 

[ajw22]

Is the Honeywell S8610U the best replacement for the original s8600? If it’s not, I can package it up and return it.

You check you have 24V at the Honeywell box?

Let's see if @swamprat69 knows about that box.

 

[swamprat69]

This should be the service manual for your heater including the wiring diagram https://www.parts4heating.com/v/vspfiles/images/pdfs/ESCSeries2.pdf
It seems that the OEM ignition module is still available??? Parts4heating.com: Honeywell S8600F Ignition Control, Natural
It appears that you need 24V between 24V gnd and 24V on the fenwal ign control in order to initiate both spark and 24V supply to MV/PV and PV on the gas valve. If you have 24V between 24V gnd and 24V on the ignition control, you can turn the gas valve to "off" and check for spark by removing the attached wire and then checking for spark with a wire from "spark" on the ign control to a good known ground with a small gap between the wire and the ground. It is possible that you are getting no spark due to a dirty pilot assembly or poor ground

 

[swamprat69]

DUH... forgot to mention, use insulated wire and insulated pliers to hold wire when checking for spark!

 

[swamprat69]

DUH... forgot to mention, use insulated wire and insulated pliers to hold wire when checking for spark!

I am soooo used to going through the steps that I would take that I sometimes forget to include the " nobody would really grab a high voltage wire with their hands and attempt to complete the circuit" part!

 

[KDpoolguy]

I took a no-contact voltage tester and got no reading. It’s supposed to sense 10v min-1000v, so it’s strange I didn’t get any reading, even the 220v.
It’s not my house, so I didn’t know where the pool equipment breakers are. Now that I do, and I’m hoping to take a look next visit, along with brining my multimeter. I imagine with no power that my next inkling is that it’s a breaker that’s tripped.

 

[KDpoolguy]

Ok, got the breaker to flip and now have power at the heater (voltage tester gets 24v at transformer). Still no light. Next step is replacing the Honeywell ignition controller. Ideas?

 

[Poolbreh]

I would probably give it a good cleaning first, quite a bit of dust. Clean all the connectors and ground with a corrosion inhibitor. I just worked on one similar not too long ago and cleaned everything really well and cleaned out the gas heads and it fired right up. But the post above swamprat says how to test. Good ground connections are necessary.