400K BTU Gas Heater Rebuild or Replace?

Dec 22, 2020
6
Dallas, TX
Hey TFPrs -

We inherited an old Teledyne Laars Lite 400N-B when we bought our new house in North Texas. Previous owners absolutely failed to keep up with basic care and maintenance. I was able to keep it structurally sound through the freeze, but it's a ways from being in working condition. I would really appreciate some opinions from follow users on cost/benefit of seeking parts and DIYing this heater back to working condition or biting the bullet for a new heater. Hint: spouse is not enthusiastic about dropping $3K-$4K on a new heater.

Known Issues:
  • The heat exchanger tube assembly is shot (tubes warped, heat transfer coils completely filled with soot and misshaped.
  • Igniter needs to be replaced
  • Water Temp Sensor shot
  • Limit switches shot
  • Ignition Control Assembly (maybe needs to be replaced)
What seems ok:
  • Water flow system
  • headers
  • gas line plumbing
  • Burner Tray Assembly
Thanks for your input!

DEK
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
25,667
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I have not gone through pricing all the parts you listed. My personal limit for repair versus replace is 50% of the new cost. If the repair approaches 50% of the new cost I replace the device.

You can keep dropping money into repairs of an old unit but it can become a money pit.

I doubt it makes economic sense to throw money into the old heater.
 

JamesW

TFP Expert
Mar 2, 2011
24,978
It's not worth renovating.

I would guess that it's more than 25 years old, but that's just a guess.

How old is it?
 
Last edited:
Dec 22, 2020
6
Dallas, TX
I have not gone through pricing all the parts you listed. My personal limit for repair versus replace is 50% of the new cost. If the repair approaches 50% of the new cost I replace the device.

You can keep dropping money into repairs of an old unit but it can become a money pit.

I doubt it makes economic sense to throw money into the old heater.
Thanks, Allen. That's a good rule of thumb and maybe even more so for newer units. New Heat Exchange Assemblies seem to around $1,300 today. So that part alone is probably getting close to the threshold.
 
Dec 22, 2020
6
Dallas, TX
It's not worth renovating.

I would guess that it's more than 25 years old, but that's just a guess.

How old is it?
Hey James. I think it's a '94 model. These older models (like older cars) are easier to keep nursing along with fewer electronics and programming. I was entertaining a fantasy that I might be able to get another season or 3 out of it before justifying an upgrade.
 
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