Pulsating high pressure

[Joswhaha]

Howdy y’all
I have 1 bay that started pulsating when on high pressure. The pressure bounces from maybe 850-1000 and it is noticeable at the gun and at the pump. Is this a common issue I could use a little guidance?

 

[MEP001]

If it started suddenly, it's most likely a simple issue like a piece of trash caught under a valve poppet.

 

[Joswhaha]

If it started suddenly, it's most likely a simple issue like a piece of trash caught under a valve poppet.

Should I order some kind of rebuild kit before I take this think apart? I just noticed it a day or 2 ago and it hasn’t changed as far as I can tell.

 

[MEP001]

You should be okay as long as you're careful with the valves when you put them back in. You may need to oil them, and be careful not to force them in. Spare valve o-rings and backup rings are essential spare parts.

 

[Joswhaha]

So I took the valves out of this pump and checked everything. One valve had some metal shavings in it and I assume that isn’t good. I cleaned them up and there is not change in the pulsating. I have a few extra pumps, would it be worth having one rebuild to have as a spare for when these go out.

 

[MEP001]

They aren't hard to rebuild, but it's definitely a good idea to have a rebuilt backup. I don't change out the whole pump, I keep a manifold plumbed with unions ready to swap out, which takes all of five minutes.

Is this pulsating constant, whether the trigger is pulled or not? Or does it pulsate only if the trigger is pulled? Does it pulsate immediately when the trigger is pulled, or does it take a few seconds?

 

[Joswhaha]

It pulses weather the trigger is pulled or not but more noticeable when the the trigger is pulled. I also noticed when the pump starts on each use it is slow to start pumping water like it is out of water and takes a second to start spraying water.

 

[cantbreak80]

It might be a caused by an air leak in the plumbing to the pump…like where the soap and wax supply connects to the pump.

Maybe try running the pump after removing and plugging the soap/wax inlet fittings at the pump.

If it now runs smoothly, look for cracked, loose, poorly taped fittings.

Air leaks are sneaky...they may not leak liquid which sometimes make them hard to find.

"Slow to start pumping"...might be a leaking boom swivel. While the bay is idle, the swivel seal relaxes allowing air into the discharge hose.
This condition will drain the hose. When the pump is turned on again it has to fill the entire bay hose before pressure builds.

 

[MEP001]

It might be a caused by an air leak in the plumbing to the pump…like where the soap and wax supply connects to the pump.

In my experience, it's more likely to be a low pressure seal failed. If there's water dripping from under the pump, it's definitely the problem.

 

[Twodose]

One valve had some metal shavings in it and I assume that isn’t good. I cleaned them up and there is not change in the pulsating. I have a few extra pumps, would it be worth having one rebuild to have as a spare for when these go out.

Where do you think the metal shavings came from?, I would look into that.
Always keep a new head ready to go.

 

[Joswhaha]

The shavings came out of one of the valves when I took them out. I couldn’t find any obvious damage but it could of come from anywhere upstream I guess.

 

[Waxman]

I had a problem like that. It wound up being the inlet plumbing being clogged with dirt and crud. Once I took it all apart and cleaned everything out it worked great.

 

[Joswhaha]

Thank you, I will take some of the inlet piping apart and see how it looks.
I am going to order some parts to rebuild the head and see if that helps to.

 

[Joswhaha]

Cat rebuild. Is this the rebuild kit I should purchase?

 

[MEP001]

No, you just need the seal kit 30623, 6 48361 valve o-rings and 6 43358 backup rings. The seal kit comes with new plungers seals. Don't change them, just save them.

I recommend keeping one set of valves on hand. They rarely go bad, but they can sometimes. 30821

 

[Mchas]

Could it also be a washed out head?

 

[Randy]

The first thing you need to do is to verify that the head is rebuild able. Are you using a 5CP or a 310 pump? Is the head seal seating surfaces washed out or are the valve seating surfaces washed out? What is the condition of the brass seal cases? Are they cupped? If you put a seal kit into a head that’s washed out you’ll be wasting $100, because it’ll last about 15 minutes before it start pulsating again. The head in the attacment is washed out, notice the groove cut in the seating surface.

 

[Joswhaha]

Thanks y’all. I have few extra heads that I am going to rebuild and switch out for the one acting up. I don’t want to shut it down without some parts on hand to rebuild whatever is wrong with it.