Complete equipment replacement help

[Terry]

I could really use some help with choosing new equipment. I'll be replacing the filter, pump, and heater. About the only thing I've been able to decide is that I'm going back with a sand filter. Haven't decided which one, but feel pretty comfortable being able to make this decision. Pump and heater research, however, is giving me a serious headache.

Some info on the pool:
Fiberglass pool 18600 gallons, spa 470 gallons.
New 2" plumbing going in as part of the remodel.
Gas available.

I'm currently looking at heater options as they seem to be the lesser of the two evils. I will be primarily, most likely exclusively, heating the spa. Have never heated the pool, nor had any inclination to do so, and as a result I'm considering going with one of the smaller heaters designed for the lower water volume.

I'm finding that a 400 BTU heater should raise 500 gallons 30 deg in 23 min.
250 BTU raises 30 deg in 38 min
100 BTU raises 30 deg in 90 min

Is this a simple math calculation? That is to say, if you run the 100 BTU heater 4x longer, are you using the same amount of gas the 400 BTU heater would use in the 23 min? If so, it comes down to wait time vs upfront cost. If not, that could affect my decision.

I have many more questions, but I'll start with this one as this seems to be the first step in narrowing down the decision.

Thanks in advance!

 

[JasonLion]

In practice, you almost always want the largest heater you can get. Think about deciding to get in the spa and then needing to wait 23 minutes for the spa to be ready, how about 46 minutes, or an hour and a half? Besides, larger gas heaters are only slightly more expensive than small ones (at least as long as your gas meter can handle it).

Slower heating does require more total gas because more heat is lost during the longer period of time, still that effect is small so it is more or less as you described.

For pumps, you will almost certainly want a two speed pump sized appropriately to run the spa. You run it on low speed for day to day pool filtering to save electricity. A variable speed pump is an option, but the extra up front costs are unlikely to ever get paid back unless your electric rates are above $0.20/kwh.

 

[PoolGuyNJ]

A Pentair Tagelus 24" sand filter has 2" plumbing.
Pentair WhisperFlo 2 Speed. Allow 1/4 HP per spa jet for High speed. If you are in Southern California or your cost per KWH is high, look seriously at an IntelliFlo.
400K BTU Pentair MasterTemp (HD version is Cupro-Nickle)

The amount of gas will used will be the same with a 100 or 400K heater. The heat up time is what varies. The bigger units do it faster.

You want the HD version. It is more resistant to low pH and chlorine than a straight copper heat exchanger. If you decide on a smaller heater, the 250K comes in an HD version too.

Purchasing all at the same time qualifies for Pentair's extended 3 year warranty. If you get an Intellichlor too, it would also get the 3 year.

Please buy it from who you plan on having installing it. If you are installing it, the net is appropriate, if you are hiring a tech, like me, buying it them generally gets much better service priority calling Pentair and waiting for a 3rd party provider. Buying from the net and then asking a tech like me to install it is like bringing your own chop meat to McDonolds and asking them to serve it to you. It might cost a bit more but the value added by the dealer's prompt service, if it's ever needed, more than pays for the initial costs delta.

Scott

 

[Terry]

Thanks for the recommendations. I have been reading and researching my options, having somewhere to start is very helpful.

As part of this project, the spa will be pulled out to replumb. We are then looking to put it back in another location, mostly for aesthetic reasons. One of the contractors suggested I look into replacing the spa with a new unit. This has opened a whole new set of questions.

If I go this route, and it is looking attractive as I can replace for about the cost of refinishing and replumbing the old spa, I have the option of plumbing it in with my pool equipment, or purchasing their equipment pack. The cost of their equipment pack is pretty close, a few hundred less, to the cost of a gas heater.

Benefits to their pack are higher HP/ multiple pumps that allow more jets in the spa.

Drawback is that their heater is small enough that it pretty much has to be kept running as the heat up time is very slow. They claim the cost to run it this way is $15-20/month. Possibly I would spend that anyway running a 400K heater, heating at use? Is there a formula I can use to calculate gas usage?

What else should I be considering here?

 

[X-PertPool]

Sand Filter, Hayward S244t (if you want 2") get the Vari-Flo XL Control Valve - 2" SP71620T
Hayward Super Pump is a work horse, if you want multi-speed go with the pentair
For heater I like Rheem/Raypak. Digital, Electronic, Cup-Nickle if you want. I usually sell the 266k BTU but you can get larger if you want. But honestly I have the 266k on a 20x40 and they were happy with it. They have a calculation table out there to see how much heat you get per hour based on gallons and ambient temperature.

Regardless Pentair and Hayward are both great names. But when it comes to heaters I really prefer Rheem.

 

[amati5]

I just replaced my pump/filter and I noticed my heater (Hayward 400 series) requires just a little more flow to work with the pump's low speed setting (removing the Kreepy Krauly will make the heater work). So, assuming the smaller heater requires less flow, I think that's a plus side of a smaller heater (no need to turn on high speed). But that's based on my filter being brand new with very little pressure while in operation. Having an oversized filter really helps with the flow.