I got lucky...now I need help adding a flow switch

[wgipe]

Evening, TFP World! We have an autocover that stays closed except when the pool is in use or needs to be left open to breath. Today, it was a beautiful day, so I left it open most of the day. I did not appreciate how much Crud was coming off the trees, and allowed both skimmer baskets to get full to the point where the pump was still pulling water, but there was a good amount of air in the pump basket by the time a caught it. The pump was not warm at all, and as soon as I cleared the skimmer baskets and turned the pump back on, it primed right up and went to town. I'm assuming I didn't do any material damage to the pump - please correct me if I'm wrong on that.

Now....what I did not like was that I had used the app to kick the heater on to boost the temp a few degrees for a night swim. Fortunately, I went out there shortly after that and caught the issue, but the heater was running even with the reduced flow through the pump. I'm assuming that there must have been sufficient flow to trigger the pressure switch, but I guess there's no way to really know - all I know is that it was running with very limited flow.

All that to say, I've seen mentioned here where folks have plumbed in a flow switch that is used in place of the pressure switch on the MasterTemps. Could someone point me to the proper flow switch? How would that be wired and to where - the IntelliCenter? Heater? I'm sure this is a pretty basic thing - so please forgive my ignorance.

Thanks, as always!

Wes

 

[Newdude]

I'm assuming that there must have been sufficient flow to trigger the pressure switch, but I guess there's no way to really know - all I know is that it was running with very limited flow

You are overthinking it. If the heater is happy with the flow, you're fine.

I had 80 oaks on .8 acres. My baskets were full of pollen or leaves 4 times a day when things were falling. Or big storms doing the same. Sometimes i thought the skimmer basket was going to break from the suction on them when removing them. The SWG and heater didnt care.

 

[JamesW]

Re-plumb to improve flow rate?

I've never been thrilled with the plumbing job that my pool builder did in 2017. The equipment pad is about 6.5' above the water line, so the pump (SP23520VSP) has its work cut out for it. I find myself having to run the pump at 90% or more to keep the heater flow sensor happy. When the filter...

www.troublefreepool.com

 

[wgipe]

You are overthinking it.

Thanks for noticing. I don’t mean to brag, but I have an honorary PhD in Overthinking.

 

[wgipe]

Okay....so because I'm paranoid and don't want to risk my heater starving for water again...and because I like to tinker with stuff....I did some research on the proper flow switch and thought I'd document it here since I see it mentioned in several other threads, but haven't seen a project documented here where the pressure sensor was swapped out for a flow switch. Below is the email I received from Harwil. I ordered the switch today and will document the installation here so that future folks have something to refer to. I've also attached the flow switch data sheet for the recommended switch here.

======================================================================================
Hi Wes,

A flow switch that is commonly used for that application is our Q-8N series flow switch.
The part number I would recommend based on plumbing size and flow rate is Q-8N/2/2/A/VITON.
This flow switch is an adjustable flow switch with an ON set point at minimum is 44 gpm and can be adjusted up to 65 gpm in a 2” pipe.
Attached is a data sheet.

The current price for the flow switch is $148.76 each.
We do have a minimum order value of $150, so either 2 units would need to be ordered or we can round up to $150.

You are welcome to purchase direct from Harwil. For purchases we accept Visa, Mastercard, and American Express.
The shipper we use is UPS, if you have an account with UPS we can use that to ship with or just add the cost to the order total.

The email to send orders to is: [email protected]

If you have any questions just let me know.

Best Regards,

​	Kyle Acres Engineering Technician [email protected] Ph: (805) 988-6800

Please know your ordering from us is tantamount to reading and accepting our Standard Terms & Conditions which can be found at the link below.

Harwil Standard Terms and Conditions


From: Wesley Gipe
Sent: Saturday, May 28, 2022 6:29 AM
To: Orders <[email protected]>
Subject: Which Flow Switch?

Hello,

I have a residential inground pool with a Pentair MasterTemp 4000BTU heater that I installed last year. These heaters have a pressure switch to sense flow, and for a number of reasons, I’d like to replace that with an inline flow switch. The heater manual shows 45GPM for minimum flow to operate. My plan is to place a threaded in the 2” PVC line to hold the flow switch and run the leads to the control board of the heater.

Based on that application, could you suggest and provide pricing for the flow switch that would be best for that application? Thanks!

Wes

 

[JamesW]

In my opinion, all heaters should have a real flow switch.

A pressure switch might have made sense back in the day when pool systems were much simpler, but a pressure switch on a modern system is stupid.

 

[wgipe]

Okay.....so I finally had the time yesterday to hook up my new Flow switch from Harwil, and it's working perfectly. Very simple - just cut a section of 2" out before the heater union (there are no requirements for straight pipe before or after the switch), installed a 2" slip x 1" NPT tee, thread the flow switch in, wire it up, and off you go. I calibrated it with a continuity tester and my FlowVis for 45GPM so it closes as the same time as the factory pressure switch. So far, it's working like a champ. I'll report back here in the event something changes.

I've seen the recommendation a number of times here to install a flow switch, but was unable to find a thread where anyone had done so. Hopefully this will help the next person with an actual model number and installation guidance.

Happy Father's Day!

Wes

 

[JamesW]

Nice.

Normally, the T is a one part T for the best fit.

By using a reducer, the paddle can sometimes sit too high.



How deep does the paddle go in this fitting?

2" x 2" x 1" Sch 40 PVC Reducing Tee - Soc x Fipt 402-249

2" x 2" x 1" Sch 40 PVC Reducing Tee is durable for long-term use. Non-toxic and corrosion resistant, this tee is made with strong PVC material. Call today to order!

www.pvcfittingsonline.com

2" x 2" x 1" Schedule 40 PVC Reducing Tee - Socket x Socket x FIPT (402-249)​

 

[wgipe]

Nice.

Normally, the T is a one part T for the best fit.

By using a reducer, the paddle can sometimes sit too high.



How deep does the paddle go in this fitting?

View attachment 425668

2" x 2" x 1" Sch 40 PVC Reducing Tee - Soc x Fipt 402-249

2" x 2" x 1" Sch 40 PVC Reducing Tee is durable for long-term use. Non-toxic and corrosion resistant, this tee is made with strong PVC material. Call today to order!

www.pvcfittingsonline.com

2" x 2" x 1" Schedule 40 PVC Reducing Tee - Socket x Socket x FIPT (402-249)​

I wondered if that would be a problem, but there is about 1/2" of clearance at the top of the paddle, and it seems to work perfectly.

 

[JamesW]

All of the manufacturers should include a flow switch as standard.

With all of the bypasses and such, it's way too easy to get pressure with no flow and damage a heater.

 

[JamesW]

You can leave the pressure switch in series to provide an extra layer of security.

 

[1poolman1]

At the very least, leave the pressure switch in the circuit. These items are engineered to be safe with the components installed. Your equipment seems fairly new. Bypassing any factory-installed equipment will void the warranty and leave you with no recourse against Pentair if there were to be an issue. Have a fire because of doing this and your insurance may not be willing to cover a modified piece of equipment. Heaters can be scary pieces of equipment if not working absolutely correct.

Just because one can does not mean one should.