Pump configuration questions...

[starion]

One of my HyPro 8GPM pumps on bay 2 had been leaking oil for a few months. Yesterday, it finally spewed oil all over the back of the motor and stand and came to a screeching halt.

I took apart all the connecting plumbing, got the pump out by itself and am contemplating a rebuild myself or just taking it somewhere. That's for another discussion however.

In looking at how things were configured, I wondered if there were a better a way to put the plumbing back together. I pretty much understand why things are where they are and their function, except for one thing.

The water input (the blue rubber hose on the left going behind the motor) is connected to (what I believe) is a zero-pressure injector (the saucer/diaphragm). The soap and wax are injected through the blue and red tube when switched on.

My question is this: what is the purpose of a zero-pressure injector and why could I not use a tree with two chemtronics injectors instead? I used the chemtronics on my automatic for chemical dispensing and they work GREAT.

Am I missing some theory of operation here? Is it simply the volume of water can't be passed by a "ball-spring" type of injector?

 

[MEP001]

The zero-pressure regulator is there most likely because the pump is fed with city pressure and you don't have a gravity-feed tank. Just for clarification, the soap and wax aren't injected but are drawn through along with the water that basically has a higher "head" than the soap and wax.

I've done a setup almost exactly like what you have - first, you might want to replumb the regulator bypass to the inlet of the zero-pressure regulator - have you noticed how the pump makes a lot of noise when people pull and release the trigger? The ZPR doesn't handle rapid changes in flow well, but returning the bypass in front of it makes the flow through it the same all the time, and it (and the pump) takes less abuse from flow changes. Second, it gives you the opportunity to locate everything but the gauge on one side of the pump so all you need is a single union fitting on each port - two fittings loosened and it's all loose.

Do you have trouble with the current setup? Rather than replace the zero-pressure regulators with injectors, have you thought about adding a holding tank for hot water?

 

[GoBuckeyes]

Mep, I also have pressure fed pumps but do not currently use the zero-pressure regulator. Instead we are using generant regulators to reduce the pressure and draw soap/wax thrrough a large injector prior to the pump inlet. A while ago I bought a zero-pressure regulator to try but never got around to it. What tips can you give me regarding there use and longevity? You mentioned re-plumbing the pump bypass to the inlet of the injector, however I have two issues with that. First, if the pump is left running in bypass, the bypassing water will can get quite hot. What is the maximum temperature the ZPR can handle? Secondly, by plumbing the bypass to the ZPR inlet, don't you run the risk of putting soap or wax into your washes water supply? If the pump is running in bypass for a few minutes, you're continually drawing in more soap or wax and pumping it back into your fresh water supply. Has that ever been a problem? Thanks.

 

[MEP001]

First, if the pump is left running in bypass, the bypassing water will can get quite hot. What is the maximum temperature the ZPR can handle?

I don't know, but the wash I replumbed had hot water only on soap; rinse and wax were cold. People leaving the pump running on soap for an extended time didn't seem to be a problem.

Secondly, by plumbing the bypass to the ZPR inlet, don't you run the risk of putting soap or wax into your washes water supply?

No; I plumbed the bypass immediately before the zero-pressure regulator. The solenoid was upstream, and whenever the pump was running it was always drawing a little water, so nothing would get back into the plumbing.

 

[starion]

Do you have trouble with the current setup? Rather than replace the zero-pressure regulators with injectors, have you thought about adding a holding tank for hot water?

No, I haven't had any trouble. I do have a hot water holding tank, right off my boiler. Any possibility of posting a picture of one of your pump setups so I can see what you mean?

 

[MEP001]