Pressure problem

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Cody

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Jan 9, 2016
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Cody
#1
Hello my name is Cody strahan and I have an masterblend eldioblo truck mount and im having problems with pressure, at high rpms I have good pressure but it pulsates at low rpms I have pressure for a few seconds and then it durasticaly goes down then back up and down and up and so on and so forth problem just started owned it for around 8 years no problems I've changed the orings in the pump took of and checked all lines for blockages changed the pressure regulator on the front of the machine and descaled and still no change, do I need to change the valves? hopping I don't have to replace the pump any information would be greatly appreciated thank you
 

Todd the Cleaner

Todd Cottino
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#2
Pumps need to be run at the proper speed. If the rpm’s are too low you will notice a drastic reduction in both pressure and flow.

There are a couple things that can be causing the pulsation, my first guess is you have a check valve that either has some sediment keeping it from closing or the check valve is just bad. You can pull the check valves out and clean them, if that doesn’t fix the problem I would put new check valves in.

If new check valves don’t fix the problem it’s time to either re-build or replace the pump.
 

Cody

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Jan 9, 2016
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Cody
#3
Pumps need to be run at the proper speed. If the rpm’s are too low you will notice a drastic reduction in both pressure and flow.

There are a couple things that can be causing the pulsation, my first guess is you have a check valve that either has some sediment keeping it from closing or the check valve is just bad. You can pull the check valves out and clean them, if that doesn’t fix the problem I would put new check valves in.

If new check valves don’t fix the problem it’s time to either re-build or replace the pump.
Pumps need to be run at the proper speed. If the rpm’s are too low you will notice a drastic reduction in both pressure and flow.

There are a couple things that can be causing the pulsation, my first guess is you have a check valve that either has some sediment keeping it from closing or the check valve is just bad. You can pull the check valves out and clean them, if that doesn’t fix the problem I would put new check valves in.

If new check valves don’t fix the problem it’s time to either re-build or replace the pump.
I have always had good pressure at low rpms with this rig this just started the other day
 

Cody

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Jan 9, 2016
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#4
Would you happen to know where the check valves would be on these machines thank you
 

Todd the Cleaner

Todd Cottino
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#5
There are 6 of them, two for each piston. If you look at the head of the pump there are 6 large cap bolts. Open those up and use needle nose pliers to pull the check valves out. There’s an o-ring in there too. Be sure the o- ring is properly seated when you put the check valves back in. Look at the metal part when you pull them out and make sure they are clean.

423BC5AE-B2F0-4251-8207-38E527C1A3AD.jpeg

Check valve:
906F5B7A-45E1-4A39-AFEA-A605FE814504.jpeg
 

Cody

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Jan 9, 2016
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#6
Ok yes I know exactly what they and were those are I have checked them and they Puch in and are clean could they possibly be week I'm ordering a new kit to rebuild it just curious thank you
 
Mar 12, 2010
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#7
Pulsation is from air leaks. Make sure all hose clamps are tight. Do you use a chemical pump?
 
Jan 9, 2016
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#8
No not as far as I now there just the cart pump and vac behind the motor I will check for air leaks is there anywhere perticular they like to leak from more than others
 

Kevin Dumas

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Aug 31, 2008
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#11
I have serviced lot of pulsating general pumps that were caused simply by worn out or heat damaged seals.
Good idea to keep a set of seals on the truck.
I believe it is General repair kit# 19 (should be able to get them for around $30)