Webtrol H10B8SS Pump Question 1

[PurewaterGuy]

Looking at the literature for the Webtrol H10B8SS Pump it states the pump works best in the 8-10 GPM range and will max out at 18 GPM.

My problem, The pump is producing 14-15 GPM and I cannot seem to get the pump down to the 8 GPM range. Any questions or suggestions appreciated.

 

[bimr]

If you put the picture into a word file, you can add labels to items in the picture.

 

[PurewaterGuy]

You have great patience. Lets try this.

 

[PurewaterGuy]

Ok, between this post and my last post we should have a pretty clear understanding of the water routes and components. Now hopefully we can get together and figure it out. Again, my main concern is the pump putting out 14 GPM yet I'm only showing 20 PSI on the final filter and my return pressure at the pumps is less than 10 PSI ,,,

 

[bimr]

Do you have the pump head curve?

The return line from the building loop should have a backpressure valve not a PRV. A backpressure valve will retain the pressure on the inlet side of the valve.

A PRV is a different type of valve that is used to reduce the pressure across the PRV, not retain the pressure.

One would think that the users on the building loop would be complaining about the low water pressure.

 

[PurewaterGuy]

Question. How would I be able to know if the valve in place is either a PRV or a back pressure valve?

There are no markings on either valve. (the one from the feed source or the one that returns to the pumps)

I take it you were able to figure out the layout from what I posted?

 

[bimr]

The valves should have a manufacturer's name and part number on them.

The flow meter is reading the recirculating flow around the pumps. It looks like there is a PRV on the recirculating line after the probe and before the temperature gauge.

A minimum flow of 30% is the usual recirculating flow for this type of pump arrangement. The recirculating flow is to prevent the pump from dead heading when no users are drawing water.

A flow meter should be installed in the building loop to determine the flow through the loop. There is no way for you to know the flow through the loop without it. You can estimate the flow by subtracting the flow on the pump curve from the recirculating pump flow.

 

[PurewaterGuy]

I'll take another look at the valves.

(It looks like there is a PRV on the recirculating line after the probe and before the temperature gauge.)

Are you referring to the valve at the low point in the picture or the valve to the top tight? ref: Pump picture

Also, should it be a PRV or back pressure control valve?

You would recommend a flow meter to be installed after the final filter as the pipe runs up the wall to feed the labs ,,, correct?

I am trying to find a pump curve schematic. I do know the feed pressure to the pumps is 65 PSI and we're recirculating at 14 GPM. - attached are some specs for the pump.

On another note: You can't realize how I appreciate this help.

 

[bimr]

(It looks like there is a PRV on the recirculating line after the probe and before the temperature gauge.)

I am referring to the device after the TEE where the piping turns upward and then turns right toward the temperature gauge. The device shoulg be an automatic Pump Recirculation Valve.

You will not know the flow in the loop unless you have a flow meter on it.

 

[PurewaterGuy]

I'm going back Monday to take a look at the valves. Did a job in Maine today. If you'd take a look at the attachment. Thanks again for all the help.

 

[bimr]

You should not have a pressure relief valve. A PRV is device that is used to prevent overpressurization of equipment. A PRV should not operate under normal conditions, only during emergencies. The PRV releases to the atmosphere. You probably do not have a PRV.

The back pressure control valve is an operating valve.

What you have is probably a pressure regulating valve:

http://www.plastomatic.com/pr.html

 

[PurewaterGuy]

Went back and checked both valves for markings today.

 

[bimr]

It looks like a pressure regulating valve. I would try a small adjustment and see what it does.

To measure any the results of an adjustment, you need pressure gauges and flow indiators on the loop.

 

[PurewaterGuy]

Should I crank the valve on the return in?

 

[bimr]

I would think that you crank the valve tighter. Don't make a major adjustment. Try one turn and see what happens.

 

[PurewaterGuy]

Probably returning there tomorrow. So which valve? The one on the return line?

I did bypass the final filter the other day, it plugged.

 

[bimr]

If you throttle the reutn line, the loop pressure should increase.

 

[PurewaterGuy]

OK ,,, I'll crank it in on the return. That shouldn't starve the pump in any way right?

So what purpose do you suppose the other valve serves?

 

[bimr]

Not really, your water is flowing in a loop.

 

[Zambo]

bimr, well done for keeping with this. It's getting exciting now, hop PurewaterGuy posts the reults of his adjustment.

 

[PurewaterGuy]

I'll be going there Tuesday to make the adjustment. I still have questions but don't want to overburden the answerers with them with all the questions at once.

I also have an idea of scrapping the two pumps altogether and going with a jet-pack style pump. I've looked at a good number of faucets there and all seem to be a dead-leg situations. There may be no need to recirculate this loop, I'm thinking along the lines of point of use applications and installing equipment where critical application is most needed. (clean up the water at POU) rather than toy with a PVC loop with dead-legs that will never meet Pharmaceutical spec to begin with.

Good idea?