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Boxxer 421 help plz

pcarr

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Sep 8, 2019
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Phillip Carr
Ok so i have a boxxer 421 and the pressure slowly drops while its building temp and then no pressure when its at temp i just put a new silencer and heat exchanger on it and new thermal relief valve new unloader valve new water pump im at a loss at to what the issue is i have took lid of tank and the dema and the thermal relief are working as they should and i have removed the out put line on pump after its at temp and pump shoots water like it should filled up bucket pretty quick. I check the temp of water in the water box when its at full temp and the most i have seen it get was 150 degrees but i have no pressure untill temp come back down to just warm water please HELP ME!!! I must be missing something i replaced the unloder/pressure regulator because i thought that was it but it made no change
 

pcarr

New Member
Sep 8, 2019
8
1
3
Real Name
Phillip Carr
Ok so i have a boxxer 421 and the pressure slowly drops while its building temp and then no pressure when its at temp i just put a new silencer and heat exchanger on it and new thermal relief valve new unloader valve new water pump im at a loss at to what the issue is i have took lid of tank and the dema and the thermal relief are working as they should and i have removed the out put line on pump after its at temp and pump shoots water like it should filled up bucket pretty quick. I check the temp of water in the water box when its at full temp and the most i have seen it get was 150 degrees but i have no pressure untill temp come back down to just warm water please HELP ME!!! I must be missing something i replaced the unloder/pressure regulator because i thought that was it but it made no change
I got it was scrolling and came across wandwizards post about check valve in the unloader and yep that was it
 
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wandwizard

Randy Dockins
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Nov 12, 2008
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I got it was scrolling and came across wandwizards post about check valve in the unloader and yep that was it
Yeah, that check valve business confused me too. I would've expected Jondon techs to know about that when they put mine on, but evidently, they didn't know to take it out and I didn't know it either. The manual just states in the parts list that the unloader is "modified". They get theirs directly from Hydramaster at a very inflated cost with the check valve removed already so they don't have to fool with it. I bought my unloader online thinking nothing of it and I just let Jondon put it on while they were doing some other service. That was a costly and extremely time-consuming mistake! I just wished I had known then what I had to learn the hard way about the quick, simple removal of that check valve. At least I know now and maybe can save some others from the same mistake.