In-ground Heater Selection

[tspenard]

[Edit] sorry, I didn't realize heaters were classified as "everything else" so I am now posting this to the correct forum. Hopefully I can go back and delete my original post in the equipment/plumbing forum or a moderator can do that if I can't.

I'm not sure if I put my pool details in my profile so here goes: 27K gallon, vinyl liner, IC40 chlorinator, DE filter, variable speed Pentair pump.

I'm shopping for a basic 250K BTU natural gas pool heater and for the same price I can get either the:

Hayward H250FDN - comes with cupro-nickel heat exchanger

or

Pentair MasterTemp 460732 - Pool repair company doing other work this summer recommends it for durability and serviceability

What is your take on which one ultimately lasts the longest? I will have a check valve between the CG and heater but the salt water at 3000 PPM worries me. I like the idea of a cupro-nickel HE, though in real world practice I don't know if it makes enough difference to worry about it. I'd just take the pool company's recommendation if it wasn't for this issue. The CU version of the Pentair is more expensive so I want to avoid that if possible.

I don't expect more than about 8 years out of the heater and we can reassess if a heater is necessary when it fails next time. It will probably be time for a liner then anyway and a series of other deck related repairs so I'm OK with an 8 year life expectancy such that an ASME rated or otherwise more expensive heater is not worth the money at this time.

I'd like feedback on this, then I'll have a couple questions about piping and electrical service to the heater depending on which model I choose. I've looked at both installation manuals and still don't understand the configurations they are proposing.

 

[ajw22]

I like the Pentair Mastertemp. Salt does not cause heater corrosion, poor pH management does. If you are careless on your pH then a CU heater may survive longer. If you keep your pH in the 7.2 - 7.8 range you ill not have a problem. CU heat exchangers are a bit less effective.

You don't need a check valve between the heater output and the SWG. There is nothing in the SWG to backflow. You do need a checkvalve between the heater and an inline chlorinator.

I recommend you plumb in a heater bypass to take the heater out of the loop if your water gets pH problems or for maintenance.

 

[tspenard]

I like the Pentair Mastertemp. Salt does not cause heater corrosion, poor pH management does. If you are careless on your pH then a CU heater may survive longer. If you keep your pH in the 7.2 - 7.8 range you ill not have a problem. CU heat exchangers are a bit less effective.

You don't need a check valve between the heater output and the SWG. There is nothing in the SWG to backflow. You do need a checkvalve between the heater and an inline chlorinator.

I recommend you plumb in a heater bypass to take the heater out of the loop if your water gets pH problems or for maintenance.

Thanks! I haven't drawn up a bypass schematic yet but I like the idea. Can one get away with one check valve and one manual shutoff valve (plus extra piping, of course) when designing a bypass circuit?

Why would a SWG not require a check valve when a puck system does? It's still concentrated chlorine, and when the system shuts off there will be a "slug" of it in the piping that can migrate backwards. That said, If I don't use a check valve and plumb the SWG vertically such that flow is downward (not sure this is possible with a Pentair DE filter - haven't purchased it yet to see dimensions in person) I guess that would really help keep the "slug" of highly chlorinated water from backing up.

 

[ajw22]

Thanks! I haven't drawn up a bypass schematic yet but I like the idea. Can one get away with one check valve and one manual shutoff valve (plus extra piping, of course) when designing a bypass circuit?

Yes. I drew the pic below for someone recently on how a bypass can be plumbed in.

Why would a SWG not require a check valve when a puck system does? It's still concentrated chlorine, and when the system shuts off there will be a "slug" of it in the piping that can migrate backwards. That said, If I don't use a check valve and plumb the SWG vertically such that flow is downward (not sure this is possible with a Pentair DE filter - haven't purchased it yet to see dimensions in person) I guess that would really help keep the "slug" of highly chlorinated water from backing up.

SWG does not have the chlorine concentration levels that a puck does. And the puck continues dissolving chlorine when the pump is off. The SWG turns off and any residual CL in the cell is not a lot higher then the pool water when off.

If you put in the bypass with a check valve that CV is at that point anyway.

Heater bypass

• ajw22
• May 3, 2019

Where to add a heater bypass

 

[tspenard]

Yes. I drew the pic below for someone recently on how a bypass can be plumbed in.



SWG does not have the chlorine concentration levels that a puck does. And the puck continues dissolving chlorine when the pump is off. The SWG turns off and any residual CL in the cell is not a lot higher then the pool water when off.

If you put in the bypass with a check valve that CV is at that point anyway.

Heater bypass

• ajw22
• May 3, 2019

Where to add a heater bypass

Thank, Allen. That's a neat looking system. I don't understand how the valve under the word "normal" works because I'm missing some context and possibly some detail in the picture. So some questions if I may:

Does that filter only have two ports hooked up, an inlet from the pump on the right and an outlet to the heater on the left?

Does the "normal" valve have three ports but only two are plumbed at present? And is the green line describing where the third port would be plumbed (a Tee would be installed in between the check valve and SWG)?

Regarding that "H" shaped set of pipes from the heater, is that bluish "pipe" with the label on it just a dummy support? I can't see it being a working Tee unless it is some sort of check valve. If it is designed to support the pipes near the heater, is that "H" shaped pipe assembly available for Pentair heater spaced plumbing, and what is it called? Same question regarding one made for Pentair DE multiport valve spacing. I'd like something like that for added strength and vibration resistance.

Thanks again!

 

[ajw22]

Thank, Allen. That's a neat looking system. I don't understand how the valve under the word "normal" works because I'm missing some context and possibly some detail in the picture.

In the drawing the NORMAL and BYPASS correspond to the colored lines and where the valve position would be.

Does that filter only have two ports hooked up, an inlet from the pump on the right and an outlet to the heater on the left?

Yes, all filters have two ports. Configurations of filters depend on type - DE, cartridge, sand - and manufacturer. There can be other ports on a filter at the MPV (Multi Purpose Valve) that give ports to drain to waste or recirculate.

Does the "normal" valve have three ports but only two are plumbed at present? And is the green line describing where the third port would be plumbed (a Tee would be installed in between the check valve and SWG)?

There are two types of Jandy valves Jandy | Never Lube Valves - 2 port and 3 port. That setup has a 2 port valve and needs to be changed to 3 port for the bypass.

Regarding that "H" shaped set of pipes from the heater, is that bluish "pipe" with the label on it just a dummy support? I can't see it being a working Tee unless it is some sort of check valve. If it is designed to support the pipes near the heater, is that "H" shaped pipe assembly available for Pentair heater spaced plumbing, and what is it called? Same question regarding one made for Pentair DE multiport valve spacing. I'd like something like that for added strength and vibration resistance.

Like you I am assuming that H is to support the pipes. I have not seen that before. That setup has a long run in the air. I think a creative plumber did it using standard PVC T fittings.

 

[jimmythegreek]

I'm a big fan of the raypak units and have one myself. The cupronickel was like 100 more I have a 266btu and it heats very well. As said you dont need a check valve with a swg theres no concentration but you can install one if you like

 

[linuxninja00]

We went with the Hayward H400 400k BTU with roughly the same size pool. As I understand it, heating the pool 10 degrees between the 250k BTU and 400k BTU uses the same amount of gas, just less time on the larger unit. It did bump me to my capacity on the NG supply from the street as I have other NG appliances, etc and I had to upgrade my meter. Can't speak to longevity yet, it's only in it's second season.

 

[tspenard]

In the drawing the NORMAL and BYPASS correspond to the colored lines and where the valve position would be.



Yes, all filters have two ports. Configurations of filters depend on type - DE, cartridge, sand - and manufacturer. There can be other ports on a filter at the MPV (Multi Purpose Valve) that give ports to drain to waste or recirculate.



There are two types of Jandy valves Jandy | Never Lube Valves - 2 port and 3 port. That setup has a 2 port valve and needs to be changed to 3 port for the bypass.



Like you I am assuming that H is to support the pipes. I have not seen that before. That setup has a long run in the air. I think a creative plumber did it using standard PVC T fittings.

As best as I can tell from the photo that H pipe looks like it was manufactured that way. There appears to be no transitioning coupler inboard of the threaded rings. The pipe material is the same diameter all the way from ring to ring on each pipe. And that label on the little vertical piece is probably a brand tag. I wish I knew what that thing was called. At any rate, I plan on supporting any long run that exists in the eventual plumbing. It will all exist over a concrete pad so it will be easy to block up a section here or there as needed.

 

[tspenard]

We went with the Hayward H400 400k BTU with roughly the same size pool. As I understand it, heating the pool 10 degrees between the 250k BTU and 400k BTU uses the same amount of gas, just less time on the larger unit. It did bump me to my capacity on the NG supply from the street as I have other NG appliances, etc and I had to upgrade my meter. Can't speak to longevity yet, it's only in it's second season.

Thanks for your input! The H series are all basically the same design from what I can tell so your unit's hookup orientations and options should be the same as the 250K. Like you I am limited in gas supply due to an approximately 40' run of 1" CPS poly line. 1" CPS has a smaller ID than the 1" IPS which is the more common pipe now, which I wish they had run back in 1996. IIRC our original Hayward millivolt heater was a 250K and it was a beast. At least 'I' was happy with it, until I had to plum it out of the system when it started leaking. So from my gas delivery restriction calculations I had better stick with a 250K class unit to be safe.

So my questions about the Hayward installation are based on plumbing orientation, gas pipe entry location, and electrical entry. If you look at a stock photo of the unit, if you are facing the side with the LCD control panel then the plumbing is on your right hand side of the unit. In that scenario, where does the gas pipe go through the housing? Can it go through either side? Does it enter from the opposite side of the LCD panel? Can it be oriented independently of the heat exchanger (which can be flipped around to point out to the left)? And where does the electrical service enter, or are there options? Does the electrical entry have a standard sized hole on the exterior to attach a Liqui-tite type of outdoor rated whip cable assembly?

I can't make heads or tails of their instruction manual. It's like they leave out every basic detail I am interested in or I'm too dense to find the info.

 

[tspenard]

I'm a big fan of the raypak units and have one myself. The cupronickel was like 100 more I have a 266btu and it heats very well. As said you dont need a check valve with a swg theres no concentration but you can install one if you like

Thanks, I was looking at the Raypak 266K. I've decided at least for now to concentrate on the two "bigger" brands due to the higher potential for support, and the low entry price. The heater is my least concern as far as wanting heated water goes, but it is my biggest concern as far as preparing for the installation and making the best value decision on the purchase.

Do you have any idea if a heat exchanger tends to corrode significantly even if one uses the bypass plumbing mode all summer, just due to the fact that there is some residual water sitting in the passages? At least when the HE is full of water it is deprived of air/O2. I'm not sure which scenario is worse, having no real world experience in this matter.

 

[linuxninja00]

Thanks for your input! The H series are all basically the same design from what I can tell so your unit's hookup orientations and options should be the same as the 250K. Like you I am limited in gas supply due to an approximately 40' run of 1" CPS poly line. 1" CPS has a smaller ID than the 1" IPS which is the more common pipe now, which I wish they had run back in 1996. IIRC our original Hayward millivolt heater was a 250K and it was a beast. At least 'I' was happy with it, until I had to plum it out of the system when it started leaking. So from my gas delivery restriction calculations I had better stick with a 250K class unit to be safe.

So my questions about the Hayward installation are based on plumbing orientation, gas pipe entry location, and electrical entry. If you look at a stock photo of the unit, if you are facing the side with the LCD control panel then the plumbing is on your right hand side of the unit. In that scenario, where does the gas pipe go through the housing? Can it go through either side? Does it enter from the opposite side of the LCD panel? Can it be oriented independently of the heat exchanger (which can be flipped around to point out to the left)? And where does the electrical service enter, or are there options? Does the electrical entry have a standard sized hole on the exterior to attach a Liqui-tite type of outdoor rated whip cable assembly?

I can't make heads or tails of their instruction manual. It's like they leave out every basic detail I am interested in or I'm too dense to find the info.

I can't really speak too much to the install as I had it done for me, I'm not a licensed gas plumber so I think it's illegal in my area for me to do that

Here's a pic of the right side with the electrical and plumbing


Left side with gas plumbing

 

[jimmythegreek]

They all accept the same size electrical connections. If you are trying to push/pull the unit with a new one it would have to be same unit. It's pretty easy to install any heater if you are comfy with this type of work. The raypaks are the best unit out there and is priced similarly to pentair and hayward and none of them will give you much warranty as a DIY install. You are correct with the sizing of unit, that's max with your 1" line and the 40' length of run

 

[cpotter638]

Like you I am assuming that H is to support the pipes. I have not seen that before. That setup has a long run in the air. I think a creative plumber did it using standard PVC T fittings.

I'm far from an expert. Looking to install a pool heat pump. In researching, I came across the "H-shaped" plumbing section. I think it is a bypass check valve:

$76.95 AquaCal STK0135 Heater bypass External

Hope this helps.
Chad.

 

[ajw22]

I'm far from an expert. Looking to install a pool heat pump. In researching, I came across the "H-shaped" plumbing section. I think it is a bypass check valve:

$76.95 AquaCal STK0135 Heater bypass External

Hope this helps.
Chad.

Chad, thaks for that point out. Never seen that. I have seen manual bypass with a Jandy valve to adjust heater flow rates.

 

[tspenard]

I'm far from an expert. Looking to install a pool heat pump. In researching, I came across the "H-shaped" plumbing section. I think it is a bypass check valve:

$76.95 AquaCal STK0135 Heater bypass External

Hope this helps.
Chad.

Awesome find, thanks. So it's more than just a support pipe setup, that H section has a bypass capability internally.

 

[tspenard]

They all accept the same size electrical connections. If you are trying to push/pull the unit with a new one it would have to be same unit. It's pretty easy to install any heater if you are comfy with this type of work. The raypaks are the best unit out there and is priced similarly to pentair and hayward and none of them will give you much warranty as a DIY install. You are correct with the sizing of unit, that's max with your 1" line and the 40' length of run

Thanks for your help and recommendation!

 

[tspenard]

I can't really speak too much to the install as I had it done for me, I'm not a licensed gas plumber so I think it's illegal in my area for me to do that

Here's a pic of the right side with the electrical and plumbing
View attachment 99767

Left side with gas plumbing
View attachment 99768

Thank you very much, those images are really helpful. I can see two ways that would be minimally obstructive, and if the gas line can come in from the right (very close to the electrical entry on your unit) it would be ideal. That's where plumbing went in on our old millivolt Hayward (no electrical service required); the gas riser is mounted in the concrete slab so it's going to stay put and I will be adapting from it. It is the main concern I have when planning how to position the eventual new heater and avoid an overly complex series of elbows and restrictions in the metal pipe sections.

 

[jimmythegreek]

You can enter from either side with most any unit. Your line will reduce to 3/4 at the heater gas valve. You can open a new hole if there isn't a bung already and keep same size pipe and then reduce in an elbow and come back into the valve. A union in there is also needed