Hydramaster 421 pressure drops

[lg2121]

When trigger is pulled pressure drops from 450psi to less than 200. Just had seals replaced less than 20 hrs ago an suggestions.
Thanks

 

[Dolly Llama]

any suggestions.

find the air leak
it's sucking air somewhere


..L.T.A.

 

[Jim Martin]

Could be something stuck under the check valves in the pump or the regulator unloader is giving you problems

 

[dealtimeman]

Is it Cavitating badly?

If yes check the inlet hoses for an air leak.

If cavitating a little, replace your check valves both sets.

 

[doylebloss]

The pump puts out 3.5 GPM the primary orifice when new is the equivalent of a #2 jet, at that pressure it will flow .7 GPM; the recommended tool for that machine should be jetted equivalent to #4 and should flow 1.4 GPM. Check these two items and most times you find the problem; the primary orifice may not be properly seated or it could be worn, I have seen it accidentally get swapped with the secondary orifice which is the equivalent of a #6 jet which at the stated pressure will flow 2.1 GPM.
Marcus Van Wyck
Lead Technical Service Representative
HydraMaster/US Products Pro | Customer Care | 11015 47th Ave W. | Mukilteo | WA | 98275 | Customer Care: 800-426.1301 ext. 1633 | Fax: 425-771-7156
www.hydramaster.com | www.usproductspro.com

 

[dgardner]

Great info!