Chem pump flowing backwards

[Charlie Lyman]

Chem pump is flowing backwards and filling up my 5 gallon chem jug. I rebuilt the chem pump thinking that a check valve was bad. It worked fine for a couple of days and it did it again today. This time it did it while I was running it on a job. Last time it did it while it was sitting in the garage not running. Any ideas?
I have a Boxxer 421.

 

[Desk Jockey]

I don't know about Hydrmaster's but on a Prochem that means there is a hole in the chemical pump diaphram.

 

[Charlie Lyman]

I replaced the diaphragm when I rebuilt it, along with all of the other o rings. The old one was worn, but no holes.

 

[Desk Jockey]

So it's driven off the cylinder like PC's?

Is that piston ok?

 

[Charlie Lyman]

I don't know. I didn't think about looking at the high pressure pump. It needs to be rebuilt, but I was thinking about replacing it instead. It has 5100 hrs on it.

 

[Desk Jockey]

5100? That baby is tired! :shock:

 

[Charlie Lyman]

The thing runs good. I replaced the engine 1200 hrs ago. Everything else works great.

 

[Desk Jockey]

Well don't go by me, I'm not a mechanic but that's a lot of hours. I wonder if the check valve in that piston isn't damaged on not working correctly.

 

[Charlie Lyman]

I'll check it in a little while, I'm looking at the diagram in the manual and that would make sense. I was also wondering if it was the 3 way priming valve.

 

[Desk Jockey]

A leak or crack in the 3-way might keep it from syphoning but I don't recall having one back flow and fill the jug. :?:

 

[bob vawter]

footvalve

 

[Charlie Lyman]

Thanks Bob, but could you be a little more specific? Where is it located? I am a mechanical idiot.

 

[Charlie Lyman]

Is that the strainer that is at the end of the hose going into the chem jug? If so, I didn't know there was a valve in there.

 

[BillC]

Give Hydramaster a call. I'm still thinking its the chemical pump.. Even if your water pump is worn the chemical pump should not allow any back-flow..

 

[Charlie Lyman]

I talked to my dist today. He said that it is probably the 3 way valve, it need to be tightened up, or replaced. There is no footvalve on a boxxer 421.

 

[bob vawter]

Is that the strainer that is at the end of the hose going into the chem jug? If so, I didn't know there was a valve in there.

not only is it a strainer ...
it is a one way ck valve.....with a ball and spring.......it will unscrew apart to clean......
and found in the mix jug on the end of the line!

 

[Chris A]

Newer hydramasters just have the strainer Bawbs, the last one I had with a valve was my 98 cds

 

[Charlie Lyman]

I took the knob off of the 3 way valve and tightened it up. I also replaced the flowmeter. It had a good size crack in it on the back. Works good now. No back flow.