Pressure spike from heat pump loop?

Jun 22, 2016
906
FL
Hi TFP. I'm still break(ing) in my new equipment and I've struggled with high pressure (25-30psi) in our plumbing system. Specifically, since our replaster. I've noticed that when I bypass our heat pump, the pressure drops to 15-20psi. Does that seem normal? And what would be causing that?
 
Grumpie,

Yes.... the more things that the water has to pass through the harder it is to push the water through.

The pressure gauge is telling you how much effort it takes to push your water through your system..

With a VS pump your really need to be comparing apples to apples... or RPMs to RPMs...

At what speed are you reading 25 to 30 PSI? I suspect that you are just running your pump at too high of an RPM..

I would see at what RPM the SWCG's flow switch turns on... I would then add 100 RPM, and that is the speed that I would run most of the time. Only increasing the speed as need to run specific functions or water features.

Thanks,

Jim R.
 
Grumpie,

Yes.... the more things that the water has to pass through the harder it is to push the water through.

The pressure gauge is tells you how much effort it takes to push your water through your system..

With a VS pump your really need to be comparing apples to apples... or RPMs to RPMs...

At what speed are you reading 25 to 30 PSI? I suspect that you are just running your pump at too high of an RPM..

I would see at what RPM the SWCG's flow switch turns on... I would then add 100 RPM, and that is the speed that I would run most of the time. Only increasing the speed as need to run specific functions or water features.

Thanks,

Jim R.

Thanks, Jim.
 
Honestly speaking, that sounds a bit high to me as it is almost a 50% change in pressure. I have very little heater experience so perhaps Mark or Paul can comment on it as I thought most of the water flow is actually bypassed around the heater core and only a small amount flows through the heater.

Brian - have you deep cleaned and rinsed your cartridges? You just went through two plaster startups in a row and cartridges can get pretty messed up from the plaster dust.
 
Honestly speaking, that sounds a bit high to me as it is almost a 50% change in pressure. I have very little heater experience so perhaps Mark or Paul can comment on it as I thought most of the water flow is actually bypassed around the heater core and only a small amount flows through the heater.

Brian - have you deep cleaned and rinsed your cartridges? You just went through two plaster startups in a row and cartridges can get pretty messed up from the plaster dust.

I have cleaned the cartridges multiple times, both before and after the refinish. But the extent of my cleaning has been hosing them clean with a high pressure fine nozzle. I have not used any cleaning agents or other chemicals/methods. They were filthy every time tho.

I know my heater was off (at the circuit breaker) during startup of the refinish, but I don't know if the PB actually bypassed the heater at the valve. So while I have very little experience and knowledge of these things, my biggest fear is that somehow I've damaged the heater and thus causing such an increase in pressure when not bypassed.
 
My logic, perhaps flawed, is whatever is going on here is also contributing to my lack of performance with my spa jets and Venturi air intakes. When the pressure infrequently drops a bit, I see better performance from both. But I can't pinpoint the cause.
 
Hose cleaning is fine for routine maintenance of the filter because most material will be simply stuck on the media surface. When you are doing a plaster startup, there is a ton of microscopic fine calcium carbonate particles that are generated. These particles can get embedded in the filter medium and basically act like a plug. I have seen some pool builds where the builder is courteous enough to use a pair of old cartridges for the startup process and then, after the 30 day period, install the owner's original cartridges so as to not foul them up...it's rare, but I have seen that before.

To chemically clean cartridges is not an easy task but it can be done by the pool owner. It's a 2-step process where you first soak the cartridges in a cleaning solution designed to remove any organics (oils, bather waste, hair, skin particles, etc, etc). Then, after you rinse that, you soak the cartridge in a diluted acid solution to dissolve any embedded calcium. The organic clean can be done with either a TSP (trisodium phosphate) solution OR with some automatic dishwasher detergent. I prefer TSP as it is simple to do and I can find it easily in the paint section of my hardware store (just be careful because there are many "green alternatives" to TSP that don't contain phosphates and yet are labelled as "TSP"...weird...). The acid soak is done with a fairly dilute acid solution, typically 9-to-1 water-to-acid ratio. You can soak all four cartridges at once by using a large plastic outdoor garbage can and putting a thick, outdoor trash bag in it. Juts add the cartridges and the cleaning solution and then tie up the bag so that everything is submerged and let it sit for a few hours. Rinse and repeat with the next solution (use a new trash bag tho...).

And please, DO NOT do this anywhere near your nice new patio....TSP will corrode the heck out of anything aluminum and muriatic acid will etch stone and concrete. Simply go to a part of your yard where it doesn't matter if you release the cleaning solution, preferably over a dirt pile. You can always hose it down to dilute everything but, honestly speaking, the chemicals will have little effect on anything given the dilutions used....

OR

You can just drop ~ $400 on new cartridges.....

As for your heater, I doubt it's damaged at all. You would have to have run it while the plaster was curing. As I said, I don't think a 50% increase in pressure is normal for a heater but I have no in-depth knowledge of them.
 
Hi TFP. I'm still break(ing) in my new equipment and I've struggled with high pressure (25-30psi) in our plumbing system. Specifically, since our replaster. I've noticed that when I bypass our heat pump, the pressure drops to 15-20psi. Does that seem normal? And what would be causing that?
Was that measured with the pump at full speed with all of the water going through the heater? Spec on those heaters are 75 GPM max. I think they have quite a bit of head loss internally and they don't have a built in bypass.

But was the pressure rise less before the replaster?
 
Was that measured with the pump at full speed with all of the water going through the heater? Spec on those heaters are 75 GPM max. I think they have quite a bit of head loss internally and they don't have a built in bypass.

But was the pressure rise less before the replaster?

Yes, pump at full speed specifically when in spa mode. Valve at 50/50.

While I'm not sure that the heater was the cause for higher pressure before the refinish, normal pressure for me was around 12-15psi. Now normal psi is closer to 25. I only noticed the drop when bypassing the heater as I was trying to troubleshoot the lack of pressure to the spa post-refinish.
 
Exactly how do you have the valves set? Can you take a picture of the setup and set the valves as you would to use the heater?
 

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Here's the valve at the heater.
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Mark,

I don't know much about heaters, but in the pic above isn't most of the water going to still bypass the heater? I would have thought that the handle of the valve should be pointed toward the word "Heater" in order for all the water to flow through the heater???

As you can tell, I'm sure, I don't have a heater.. :p

Thanks,

Jim R.
 
The OP was running the Intelliflo at full speed so I don't think it would be a good idea to send all that flow rate into a heater that specifies 75 GPM max. If the RPM were set lower than 2500 RPM, then it is probably safe directing all the flow rate to the heater.

However, this isn't the issue. The issue is that there is a 10 PSI pressure rise when the valve is set mid-way between bypass and heater only which seems a little excessive even for a heater without an internal bypass.
 
It does not make any sense to me, even if the heater was completely plugged up.

So when he turns the valve to shut off the heater, the pressure is lower than when he turns the same valve so that water is directed to both the heater and the bypass and the pressure goes UP???

I just can't see any obvious reason for the pressure to go up, no matter what was wrong with the heater loop?

Jim R.
 
So to clarify, when I bypass the spa, the psi drops. Which seems logical. My question was more of is a 10psi increase normal when I move the valve to the position pictured (which I believe to be a 50/50 diversion). It may have always been like this before the refinish and I just never noticed.

My bigger concern is my spa jet pressure. In spa mode (with the heater valve in the position as pictured) I wanted to make sure I wasn't losing pressure to the jets as a result of some blockage or pressure build up at the heater.

I have not yet taken the valve apart but can give that a try.
 
My question was more of is a 10psi increase normal when I move the valve to the position pictured (which I believe to be a 50/50 diversion).
The position of the valve in the picture should really be called 100%/100% (i.e. no pipe is closed off) so pressure should be at it's lowest point not it's highest. Something may be wrong with that valve. I would take it apart and have a look at it

Also, what position is the valve in when the pressure drops?
 

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