quick fix for dying boxxer 421 potentiometers

racebum

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Jul 14, 2010
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if any of you have a boxxer 421 and notice the potentiometer goes out....like yearly it's rooted in the design. they are not sealed and moisture causes rust and after time the contacts are shot often causing an overheat situation where the potentiometer basically does nothing.

welcome to china

bourns has a 500ohm potentiometer for $1.90 and it works great on the boxxer

part number is 3590S-2-501L 500 and they are on ebay direct from china for a whopping $1.90 each. so far they are more reliable than what hydramaster is selling is for $31 which is the older boxxer 427 stat

drawbacks? it's 10 turn which means you basically count how many turns you need from base for your various temps. not hard once you get the hand of it. one setting may be 4 turns another 6 etc. you can overheat if you crank it to max as 500ohms is too hot and you will trigger the safety shutdown after running awhile.

i did a year long test before i made this post just to see if there were any issues. so, if you, like me, get mad at paying $31 for a $2 dollar part now you can pay $2 for a $2 part :)
 

wandwizard

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Good tip. I've never had a problem with that part as far as I know. Jondon is super high on certain parts. I bought a chemical check valve from them that cost over 140. It was different than the one that had been on my Boxxer 421. Not too long after I found the identical one, brand new, for about 30. on Ebay. I mean the EXACT same one that had been on my machine that lasted over 14 years! I went ahead and bought it just in case. Good thing I did because I think I'm already having problems with the one I bought from Jondon. A check valve shouldn't be that much. Now, the same check valve I bought is a whopping 184.00 less than 2 years later. Crazy, insanely, stupid high! Here is the part I'm talking about. http://www.jondon.com/check-valve-80-psi.html I have no idea why they would charge such an insanely high price for this part. It is WAY, WAY out of line.

I'll say also, a 184.00 check valve should last FOREVER. The very least they could do is give you a free rebuild kit for it at that price. Should be several rebuild kits. I don't even think they sell a rebuild kit for it because then you could fix the darn thing cheap. They do the same thing with the Dema solenoids. Super high price and no rebuild kits offered. Their price for those solenoids has been well over double normal retail of what other places charge for many years. http://www.jondon.com/solenoid-high-temp.html

Sorry for the rant, but you got me started! :D
 
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racebum

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that check valve is the other pain in the ass boxxer part. thankfully they have that rebuildable one now where you can change the o rings, spring and ball for under $20

list on the 421 potentiometer was like $100 but the $31 427 one worked basically the same

1000%+ markup bothers me so i figured if someone saved a few bucks this way, all the better.

never buy those new old stock 1pc checkvalves, they are throwaways. there is an updated one that came out 2-3 years ago that i haven't had any trouble with. the old one would fail like clock work every 300 hours or so