Heat Pump plumbed - PSI spiking

[davids94]

My Raypak 5450 heat pump was plumbed in a few days ago. I would have plumbed it myself but used a local CPC for warranty purposes. A flowvis, bypass, and waste port were also added in addition to a replacement ball valve for the inlet from my main drain. After the work I noticed the PSI on my filter guage jumped to just shy of 20 where I was in the 10/12 range prior. Is this normal / anticipated? My system is 1.5", the Raypak uses 2". Thanks!

 

[ajw22]

What happens when you turn on your heater bypass?

I think HP's do increase the pressure.

@mas985 may have some thoughts if this is normal.

 

[setsailsoon]

David,

Welcome aboard!

We need some more information. Can you please add photo of the entire equipment pad and of the piping and valve changes. Once you do that can you please add equipment and model numbers to your "signature". 10 psi doesn't seem way to high. My pool with similar equipment ran about 18 psi. The expected pressure drop would be the sum of the pressure drops of the equipment added. We need to know the flow rate to check and for that we need your pump model plus the drop of the other items added. I've added the pressure drop table for your heater below. If you have 50 gpm flow the drop in the heater could be 10 psi. The table appears to be in psi based on the note but isn't completely clear.

To add a "signature" click on your screen name above right and select "signature". A box will open that will allow you to type it in. Please don't forget to press SAVE. Add things like pool type, size, equipment and model numbers plus anything unique about your pool.

I hope this helps.

Chris

 

[mas985]

According to the table, for a 10 PSI rise, you would need about 50 GPM. I think the issue is you are trying to force too much water through the heater. Is the bypass closed? It should be open some to reduce the pressure. Or if you have a VS pump, you could reduce the RPM to get the flow rate below 40 GPM.

 

[davids94]

David,

Welcome aboard!

We need some more information. Can you please add photo of the entire equipment pad and of the piping and valve changes. Once you do that can you please add equipment and model numbers to your "signature". 10 psi doesn't seem way to high. My pool with similar equipment ran about 18 psi. The expected pressure drop would be the sum of the pressure drops of the equipment added. We need to know the flow rate to check and for that we need your pump model plus the drop of the other items added. I've added the pressure drop table for your heater below. If you have 50 gpm flow the drop in the heater could be 10 psi. The table appears to be in psi based on the note but isn't completely clear.

To add a "signature" click on your screen name above right and select "signature". A box will open that will allow you to type it in. Please don't forget to press SAVE. Add things like pool type, size, equipment and model numbers plus anything unique about your pool.

I hope this helps.

Chris

View attachment 98148

Thanks Chris! My signature has been updated - appreciate the guidance on making those changes. Here's some photos. While I was out there today I realized that the bozo who plumbed it missed a valve entirely as I see it. The setup allows flow into the outlet of the heat pump if the "Bypass" (not a bypass at all) is closed. Shame on me for not taking a closer look before now. The electrician will be here Wednesday to wire it. Thanks

 

[davids94]

According to the table, for a 10 PSI rise, you would need about 50 GPM. I think the issue is you are trying to force too much water through the heater. Is the bypass closed? It should be open some to reduce the pressure. Or if you have a VS pump, you could reduce the RPM to get the flow rate below 40 GPM.

Thanks for your input! According the the flowvis i'm at a bit over 40 GPM and my pump is running at 2600 RPM. The bypass is open. Should i reduce the pump RPM further? Also, please take a look at the photos I posted of the setup above. I noticed today while I was taking these snapshots that the installer missed a valve for the bypass! Geesh... thoughts?

 

[ajw22]

You are missing a check valve on the output side of your heater so the water only flows one way when the bypass valve is used.

 

[CJadamec]

You heat pump is plumbed correctly. The 3-way valve is all you need for a bypass setup. The way it is plumbed is very efficient and uses the fewest number of valves. There are a few extra fittings but it looks like they were trying to make it easier for you to get to the filter. You can throttle the 3-way valve to adjust the amount of flow going thru the heater. You don't need any check valves as the pressure differential inside the valve takes car of that for you. If you do throttle that valve the flowvis is not going to tell you how much water is actually going thru the heater. Only how much water is returning to the pool.

According to the flovis instructions it is installed in a "very bad" location. They warn about the potential for damage due to the in-line chlorinator if you are actually using the chlorinator to feed tabs. It also says it should be mounted vertically or horizontally not on a 45 degree angle like it appears to be mounted. Not sure it matters but they do make a point of not including an angled installation in their depictions of what is "ok".

2600 RPM seems rather high to me for this setup.

 

[ajw22]

You heat pump is plumbed correctly. The 3-way valve is all you need for a bypass setup. The way it is plumbed is very efficient and uses the fewest number of valves. There are a few extra fittings but it looks like they were trying to make it easier for you to get to the filter. You can throttle the 3-way valve to adjust the amount of flow going thru the heater. You don't need any check valves as the pressure differential inside the valve takes car of that for you.

If the heater core is leaking it will not maintain the pressure differential to prevent water backflow. Or if the heater was disconnected from the lines for maintenance.

That backflow valve is not fully functional in my book. The CV ensures the heater can always be bypassed.

 

[CJadamec]

Sorry yes you are correct, there should be a check valve or regular valve on the outlet of the heater. To allow the heater to totally be isolated.

Easy enough to do if and when there is an issue with the heat exchanger.

 

[mas985]

Thanks for your input! According the the flowvis i'm at a bit over 40 GPM and my pump is running at 2600 RPM. The bypass is open. Should i reduce the pump RPM further? Also, please take a look at the photos I posted of the setup above. I noticed today while I was taking these snapshots that the installer missed a valve for the bypass! Geesh... thoughts?

From the picture, the handle of the bypass valve is pointed down so the bypass is actually closed not open which is preventing water from bypassing the heater. You need to turn the handle clockwise a little and you should see the pressure drop and flow rate increase.

Alternatively, if you are interested in the minimum flow rate possible, you could drop the RPM down to 1625 and flow rate should drop to about 25 GPM.

 

[davids94]

If the heater core is leaking it will not maintain the pressure differential to prevent water backflow. Or if the heater was disconnected from the lines for maintenance.

That backflow valve is not fully functional in my book. The CV ensures the heater can always be bypassed.

Should I move the flowvis just downstream of the Heat pump outlet? That way I gave GPM isolated to just the heat pump and a check valve in place? It's really unfortunate that the flowvis is now glued in- especially very bad location.

 

[ajw22]

Should I move the flowvis just downstream of the Heat pump outlet? That way I gave GPM isolated to just the heat pump and a check valve in place? It's really unfortunate that the flowvis is now glued in- especially very bad location.

I would not cutout the Flovis and move it. It may deteriorate prematurely due to the CL or it may not. It will probably take years for anything to happen to it. Just keep an eye on it.

Cutting in a standard CV or a Jandy valve in the heater output should be easy.

 

[davids94]

I would not cutout the Flovis and move it. It may deteriorate prematurely due to the CL or it may not. It will probably take years for anything to happen to it. Just keep an eye on it.

Cutting in a standard CV or a Jandy valve in the heater output should be easy.

Is a jandy superior to a ball valve? I have a ball valve on hand. Or am I best served with a check valve?

 

[ajw22]

Is a jandy superior to a ball valve?

Yes, very! I was not going to comment about it but all those red ball valves are likely to become problematic in a few years. They get hard to turn. Especially if not exercised often.

I have 20 year old Jandy valves that still turn easily.

 

[davids94]

From the picture, the handle of the bypass valve is pointed down so the bypass is actually closed not open which is preventing water from bypassing the heater. You need to turn the handle clockwise a little and you should see the pressure drop and flow rate increase.

Alternatively, if you are interested in the minimum flow rate possible, you could drop the RPM down to 1625 and flow rate should drop to about 25 GPM.

What is the advantage to the lower rpm/ flow? I imagine I will use less pump power but with less water flowing through the heat pump won't it be running longer? Thanks!

 

[ajw22]

I imagine I will use less pump power but with less water flowing through the heat pump won't it be running longer? Thanks!

The HP puts the number of BTUs it generates into the water flowing through it. With less water volume the heater output temperature will be higher. Your pool will get the same amount of BTUs and temperature rise regardless of water volume flowing through the heater. You just need to stay within the heater minimum and maximum flow specs.

 

[CJadamec]

Yep as long as there is enough flow for the heater to run you are getting all the heat it can make.

 

[davids94]

The HP puts the number of BTUs it generates into the water flowing through it. With less water volume the heater output temperature will be higher. Your pool will get the same amount of BTUs and temperature rise regardless of water volume flowing through the heater. You just need to stay within the heater minimum and maximum flow specs.

Got it, awesome! One other item I just noticed, the guy who plumbed it installed the drains for winterizing which are integrated into the unions pointing up. Any thoughts on how to address that? I do get hard freezes here occasionally. Thanks!

 

[ajw22]

Got it, awesome! One other item I just noticed, the guy who plumbed it installed the drains for winterizing which are integrated into the unions pointing up. Any thoughts on how to address that? I do get hard freezes here occasionally. Thanks!

You mean your heater?

I see what you mean on Page 35 of the manual - https://cdn.globalimageserver.com/FetchDocument.aspx?ID=A6A43ED9-CCB9-4449-B4AF-AF6111D27828

If you intend to close the pool and winterize it then you need to have that fixed or you will need to open up the unions to blow out the coil.

Or you can plan to keep your pump running in any forecasted freezes.