Heat Pump Newbie

[anthony21078]

As this pool season comes to close in NY, I am starting to plan my spring heat pump installation. Right now I am at the baby phase of learning about heat pumps.

First question....all the plumbing for my pool, pump, filter etc. is 1.5". All the heat pumps I am looking at in the 125k btu range are 2".

Does this restriction pose a problem for the heat pump or is a reducer the simple answer with perhaps the only issue being less gpm?

 

[wireform]

You can reduce without a problem. The heat pump will not know the difference.

 

[anthony21078]

You can reduce without a problem. The heat pump will not know the difference.

That was quick

 

[wireform]

There's lot of heat pump/gas heater threads on the forum. Do your reading and ask your questions before buying and moving forward.

 

[anthony21078]

I have a few questions regarding heat pumps that may seem silly but I am just starting to learn about these things. My pool and pool equipment are rather simple. 18x36 in-ground (27000 gal). Hayward vs 500 pump, hayward de filter, stenner pump, 1.5" plumbing. Pool panel only has a 30amp service.

I am leaning towards a Aquacal heatwave superquiet likely in the 120k -140k btu range that I will be installing myself. I would like to keep the pool in the 78-82 degree range from April to October.

I will be trenching and installing 6/3 uf-b wire with a 60amp gfci breaker in the main panel to a disconnect box somewhere near the heater. Do I need 6/3 or 6/2 wire? I have read that some units dont have a neutral?

I run the pump from 11am-6pm and 2am-6am for 10 hours/day at 1650rpm using the built in timers. I have found this speed to work best for my needs in regards to skimming.

Currently I do not have a solar cover but I will purchase one when I install the heat pump. The heat pump will be placed next to the pump after I make a new pad.

The in-line chlorinator will be removed from its current spot (directly after the multiport valve) and possibly placed after the heat pump right before the bend into the ground or completely removed. I only use it to get the cya up to par at the beginning of the season when using pucks. However, I may remove it completely because now I have the stenner.

Questions
1)Does the heat pump have built-in timers that I would program to run during the times that the pump is scheduled to run? If not, what determines when the heat pump is on or off? I have read there is a flow switch that activates/deactivates the heat pump. Is it a combination of flow and water temp that activates the heat pump?

2)I see the Aquacal heat pump has a minimum of 30 and max of 70 gpm. How can I determine what rmp I should run the pump at to achieve the required gpm? Ive attached the flow sheet for my pump.

3)I know there will be some trial and error to figure out if I need to run the pump for more then 10 hours/day but is it likely that the pump will have to run for a much longer duration to achieve my desired temp? (Perhaps in the colder months but maybe not July/August)

4)I think the plumbing is pretty easy (I put a new 3-way jandy, some unions and the adapter for the stenner this season by myself). As far as plumbing is concerned, I will install a bypass but I don't know if I need a check valve?

 

[anthony21078]

up...

 

[Homebrewale]

To answer number 1, my heat pump does not have timers. If there is inadequate flow through the heater, then it will not come on. On the display, I'll see "FLO" which means flow through the heater is inadequate. If there is adequate flow, then the set temperature on the heater determines if it comes on or not. My SWG requires a lower flow rate than my heat pump. Therefore, if there are times that I want the SWG to be generating but the heat pump not to be running, I program my VSP to run at a speed where flow is fast enough for the SWG but too low for the heat pump.

To answer 2 and 3 at the same time, it is a trial and error process to find the rpm a VSP has to run to operate your heater and other equipment. If you really interested in seeing if the flowrate meets the specs on your equipment, you can install a FlowVis flow meter. There is a Jandy check valve after my pool heater so I bought and installed their retrofit kit in it. My testing indicates the heater is shutting off about when it should. During the test and error process, you should run it both when the filter is dirty and when the filter is clean. When my sand filter nears the pressure reading where I should backflush it, the lower flow rate through the system affects when they come on or stop working.

 

[anthony21078]

To answer number 1, my heat pump does not have timers. If there is inadequate flow through the heater, then it will not come on. On the display, I'll see "FLO" which means flow through the heater is inadequate. If there is adequate flow, then the set temperature on the heater determines if it comes on or not. My SWG requires a lower flow rate than my heat pump. Therefore, if there are times that I want the SWG to be generating but the heat pump not to be running, I program my VSP to run at a speed where flow is fast enough for the SWG but too low for the heat pump.

To answer 2 and 3 at the same time, it is a trial and error process to find the rpm a VSP has to run to operate your heater and other equipment. If you really interested in seeing if the flowrate meets the specs on your equipment, you can install a FlowVis flow meter. There is a Jandy check valve after my pool heater so I bought and installed their retrofit kit in it. My testing indicates the heater is shutting off about when it should. During the test and error process, you should run it both when the filter is dirty and when the filter is clean. When my sand filter nears the pressure reading where I should backflush it, the lower flow rate through the system affects when they come on or stop working.

Very helpful. So basically, no timers for the heater just a matter of flow and temperature will determine if the heat pump comes on. Easy enough.

That flow meter you suggested looks like a great tool. Probably would help determine the best speed for the VS pump to maximize efficiency for the heat pump.

Can anyone else provide info on the wiring in regards to needings a neutral wire? 6/2 wire is roughly 1$ cheaper per foot then 6/3 and 160 feet of wire is not cheap.

 

[RHanna]

I'll bring this up because of your location. I believe most heat pump will not work if ambient temperature is below 50. I don't know if a natural gas heater is possible but you could check it out. Running the natural gas line will most likely be more expensive than running the wire for a heat pump.

Since I'm in TN energy is pretty cheap, ambient temperature is adequate, and we normally use our pool all the time vs only on the weekends. That's why I went with a heat pump.

 

[scdaren]

Very helpful. So basically, no timers for the heater just a matter of flow and temperature will determine if the heat pump comes on. Easy enough.

That flow meter you suggested looks like a great tool. Probably would help determine the best speed for the VS pump to maximize efficiency for the heat pump.

Can anyone else provide info on the wiring in regards to needings a neutral wire? 6/2 wire is roughly 1$ cheaper per foot then 6/3 and 160 feet of wire is not cheap.

You really want some kind of a timer, even if it's just from the timer your pump is on. Reason for this is that heat pumps are more efficient the more ambient heat is outside. So you really want to try to run your heater during the day when it's warmer, and certainly not when it drops down below 55 degrees. Where I am in central California, my heat pump works great for the use your describe. But in your location, for April to October, I think you really want to look at natural gas.

Also, I think 125k is going to be on the low side. My 140k btu heats my 15,000 gal pool one degree per hour. I think with what you are planning, your pump is going to be running a lot. So you need to look at your cost of electricity. My 140k pump uses about 7500 watts of power, and at my California electric rates that can really add up.

 

[anthony21078]

I'll bring this up because of your location. I believe most heat pump will not work if ambient temperature is below 50. I don't know if a natural gas heater is possible but you could check it out. Running the natural gas line will most likely be more expensive than running the wire for a heat pump.

Since I'm in TN energy is pretty cheap, ambient temperature is adequate, and we normally use our pool all the time vs only on the weekends. That's why I went with a heat pump.

You really want some kind of a timer, even if it's just from the timer your pump is on. Reason for this is that heat pumps are more efficient the more ambient heat is outside. So you really want to try to run your heater during the day when it's warmer, and certainly not when it drops down below 55 degrees. Where I am in central California, my heat pump works great for the use your describe. But in your location, for April to October, I think you really want to look at natural gas.

Also, I think 125k is going to be on the low side. My 140k btu heats my 15,000 gal pool one degree per hour. I think with what you are planning, your pump is going to be running a lot. So you need to look at your cost of electricity. My 140k pump uses about 7500 watts of power, and at my California electric rates that can really add up.

I do not have natural gas in my area and propane is over 5.50$ a gallon delivered. No solar either. Heat pump is the best/only option for me.

I've settled on the Aquacal 225 which is 140k btu. Looks to be highest output for a electrical heat pump.

The timer makes sense as opposed to running solely based on temp and flow. I guess its not really practical to run the heat pump in the late hours of the night when temps are cooler and nobody is using the pool. The VS pump obviously has a built in timer so I have no idea if I can connect the VS pump timer to work with the heat pump. I do not have any type automation or external controllers.

The only idea I have is to use the aquacal poolsync module to control the heatpump. It states it has the ability to create schedulues. Do you guys think this is my best option?

PoolSync® - AquaCal Website

PoolSync® Documentation

www.aquacal.com

 

[scdaren]

I do not have natural gas in my area and propane is over 5.50$ a gallon delivered. No solar either. Heat pump is the best/only option for me.

I've settled on the Aquacal 225 which is 140k btu. Looks to be highest output for a electrical heat pump.

The timer makes sense as opposed to running solely based on temp and flow. I guess its not really practical to run the heat pump in the late hours of the night when temps are cooler and nobody is using the pool. The VS pump obviously has a built in timer so I have no idea if I can connect the VS pump timer to work with the heat pump. I do not have any type automation or external controllers.

The only idea I have is to use the aquacal poolsync module to control the heatpump. It states it has the ability to create schedulues. Do you guys think this is my best option?

PoolSync® - AquaCal Website

PoolSync® Documentation

www.aquacal.com

Your VS pump timer will automatically control the heat pump, because it will only run if there is flow going through it. So you just need to make sure your pump schedule is compatible with best times for heat pump. If you have time-of-use electrical rates, try to fit in with those best you can. Otherwise, set it to run in the late mornings and afternoons. It actually feels really nice when people are in the pool having that heat come out of the returns. Our pool has sheer descent waterfalls, and it feels SO nice to sit under those with the heat running. Once you have it set up, you'll start getting a feel for your nightly heat loss (which will be a lot without a solar cover), and how many hours it will need to run to bring your temp back up. With lows in the lower 60's and heat pump set to 86, I usually see about 3 degrees nightly loss with the cover on, or about 6 degrees with the cover off. The heat pump will click off once it reaches the temp you have it set to.