RayPak 405 Heater - Leaking


New member
Apr 5, 2021
S Cal
New member, my first post, but I heard this is the place to be when it comes to pools :)

So I have a 17 year old, Raypak 405k RP2100 Digital low nox heater that I installed in 2004. Last fall it started leaking water out the bottom and I had a pretty good idea that the heat exchanger (tube bundle) was shot. Today, since the weather here is starting to warm up, I took a look at it and confirmed there is a hole in one of the copper heat exchanger tubes. I also discovered that the spring for the bypass valve is broken and the shaft is pretty rusted/corroded so at this point I am probably looking at around $1,000 in parts, with me doing all the work.

I started pricing out a similar replacement unit and it looks like they are in the $2,400 to $3,000 price range or higher. I usually don't like to spend this much money on something that is this old (16 years) but everything else appears to be in good shape. The burner tubes look decent and I just replaced the igniter assembly last summer (around $100). Also, since I already have everything apart, it would be a lot easier to replace the bad parts instead of installing a brand new unit.

But, since I do not have a whole lot of experience with pool equipment, would I be making a mistake to spend $1,000 fixing this unit versus just replacing it outright? (I don't have money to burn, but I want to make the right decision here) There does not appear to be a whole lot to these pool heaters

Next, is there a recommended place to buy these parts from besides Amazon? From what I can tell, the tube bundle is listed at about the same price everywhere - $879. That was pretty easy to find, but I am struggling to come up with the right parts for the bypass valve. It looks like I need the
Raypak 006717F Bypass Dam/Shaft, the Raypak 006716F Bypass Valve and then they sell several springs to go with it.

Here is what I am working with:


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Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I would not put $1,000 into that old of a heater. Time to start over with a new heater for another 17 years. You got your money out of that one and it does not owe you anything.
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