Pool Heat Exchanger Assistance...

[Dispo96]

I'll start this by saying I'm new to boiler systems and I will attempt to explain this the best I Can, if I can give you more information, please ask and I will do my best.

I have a Gas Boiler that is on a closed circuit glycol feeder that is set to 69C with a differential of 10.

Its feeding a A&R H.I.G.1S , 140000 BTU heat exchanger.

I just bought this house so if you need more information please let me know.

The heat in and out are definitely different temperatures but I can't get my pool warmer than 26C, The thermostat that's wired at the pool to the boiler calls for 30 Degrees, I know it's calling because the boiler is always on. The water was 10C when I moved in, the pool hadn't been used in quite some time and now I've got it up to 26C, it stays at 26 consistently without drops but I Can't get it any higher.

What would be the reason to this?

 

[jebatty]

Winter? LOL But in a more serious tone, lots of reasons, one of which could be that the heat loss from the pool is greater than the heat input into the pool. I don't have a pool, just a lake that now has 75 cm of hard, white stuff on top of 0C liquid. Bummer. Others who have pools and heat exchangers likely will have better advice.

 

[Dispo96]

I would like to say it's because of winter but it's an indoor pool with a heated floor and it's been +10 outside. I thank you for your thought process however!

 

[brant2000]

What are your temperatures (pool side) heading in and out of the HX?

For the most part it really comes down to the basic thermal laws. Heat (thermal energy) always flows from hot to cold...IOW as long as your pool is warmer than anything in contact with it, it is always going to be losing heat to its surroundings. In order to supply enough heat to: 1) counter the heat being lost to its surroundings and 2) increase the average temperature of the pool, you'll obviously need to supply it with enough water, at sufficient temperatures, for a long enough time. Considering there's both a lot of water, but also signficant amounts of concrete/soil/other materials surrounding the pool, that could take some time.

 

[Dispo96]

I wont have a heat gun available for about a week or so, due to I don't want to buy one because I know someone that has one so I can't give you in/out temperatures, however the in I can only touch for a few seconds, the out I can hold on to for 10 or so, there is definitely exchange happening and the out is definitely hotter than the pool, but it's like the raising of temperature is all but standstill, it went from 10~ to 26 in about 6 days, past that it wont climb.

 

[Boil&Toil]

Assuming the heat exchanger is doing what it's supposed to do, the heat loss from the pool at 26C with the outside world at 10C is 140,000 BTU/hr (to mix some units) by the empirical fact that the temperature is stagnating there. I guess you could sanity check with your gas meter and the efficiency (claimed) of your boiler to see if it's consuming 33.6 (/eff) therms per day. ie, 37 therms/day for a 90% boiler, 42 for an 80% boiler.

Odds are excellent that the pool insulation is not what you'd hope for, especially if you are trying to run it at 30 C. The only things that come to mind that would be quick and easy are top surface insulation - either the "floating ball insulation" that you can leave in place and swim through, or an insulated cover you could put in place when not swimming. Other than that, more heat exchanger (the crude engineer would drop 300-1000 feet of PEX into the pool...the fancy one would add another heat exchanger, and check the boiler size to see if you also need to add another boiler, or if the one you have could run two HX.)

 

[Dispo96]

Thanks for your input everyone. The pool eventually went up to about 29~ than the pump the guy had there lost prime, melted everything and i'm now working back up-to that point.

I've now replaced my pump ect and have to re-heat my pool lol so I guess where I'm sitting now is , would it be worth it to replace the HX, how do I know if it's working to efficiency? Sometimes when I hold the in, the out is a lot cooler, (on the HX), however sometimes when I hold the in, the out is the same temperature, almost like it's not exchanging efficiently.

How do I checck to see if my boiler is consuming what it's supposed to? I have two identical boilers, I could get the models for you.

The heat exchanger that is there is this one :

 

[Bob Rohr]

What size boiler do you have connected to it? How many gallons in then pool? It takes a lot of BTU to do pool heating.

A&R is still around they made indirect tanks and HXers for some years back in the late 90's. They were more of a truck accessory stainless fabricator. Their tanks were fairly leak prone.

They probably have spec sheets somewhere to tell you what to expect at various flow rates and temperature differences.

Usually those tube HX required fairly high operating temperatures from the boiler to get even close to the rated output. I'd guess you need 12- 14 gpm at 180F supply to get much performance.

 

[Dispo96]

It is a : Weil - McLAIN CG Series 11

Pool is roughly 18KGallons

By leak prone, do you mean that the Glycol could be leaking in to my pool? -_-;;

 

[Smoke Signals]

How do I checck to see if my boiler is consuming what it's supposed to? I have two identical boilers, I could get the models for you

The boilers are gas? clock the meter.

 

[Bob Rohr]

It is a : Weil - McLAIN CG Series 11

Pool is roughly 18KGallons

By leak prone, do you mean that the Glycol could be leaking in to my pool? -_-;;

I meant their indirect tanks had some leak issues.

Typically for a covered, inground pool that size you want around 300,000 BTU, if you expect any recovery. I think you have about 1/2 the capacity you need, to raise the temperature or maintain it, depending on the cover, which makes a bi difference. When it's on

Location matters also, if it gets any wind, that will strip heat quickly. Fences or hedge rows help pools in windy areas.

Plenty of online pool sizing guides. It's an expensive hobby keeping pools warm. Sort of like heating the great outdoors.

 

[Dispo96]

My pool is IG/Indoor, the outside world has little effect on my pool. What's a 300,000 BTU HX go for? Would that actually heat my pool a lot quicker?

 

[Bob Rohr]

My pool is IG/Indoor, the outside world has little effect on my pool. What's a 300,000 BTU HX go for? Would that actually heat my pool a lot quicker?

A larger HX, capacity wise, only works if you have enough boiler output to drive it.

Remember too, with an indoor pool, you either heat the space, to lower the load on the pool heater. Or the pool itself heats the space. There is no free lunch

If it's 0 degrees outside, the walls and or windows around the pool also lose heat, either the pool makes that up, or the heat in the room. Keep the room at 80F, and the pool heater load drops.

The biggest problem, or challenge with indoor pools if handling the humidity and moisture, especially when uncovered.