Heater question for indoor pool

Hello, I have posted on this site before for those who remember me, I bought a foreclosed house with a small inground pool that is surrounded by a sunroom. When I bought the house, the pool water was black/brown/green. I have since followed advice on this site, and for probably less than $50 or so, I now have the pool water crystal clear. I was also having issues with the pump pressure..was around 28. What wonders a new filter can do!! I had kept the old filter (cartridge) while I got the water to a certain clarity point so that I did not subject the new filter to all that crap. Once I installed the new filter, viola, pressurre now hovers around 18. Here is my next new problem. The pool has a heater. All the pool equipment (filter, pump, heater) is in the basement of my house. I turned the heater on, and it seems to work fine. I set a temp and it was slowly raising the temp of the water. However, I noticed it was getting kinda "steamy" in the basement while running the heater. The heater has a vent that comes out of the heater, goes through the basement crawlspace to a vent that leads outside. There is also what appears to be a kind of mini fan that I think blows this exhaust outside once it reaches this point. I checked outside, and could see that air/moisture was definitely being vented outside. The crawl space was really steamy. Here is the question, how do I know if the heater is vented correctly? Natural gas scares the hell out of me and I am afraid it may not be vented properly. Would it be common for the basement to have this "steamy" effect? I took my Carbon Monoxide detector down there for a few minutes and it did not register anything. Anyone have any ideas or answers? Thanks in advance!

We also have an indoor pool and all the equipment is in the basement. Typically a fan is suppose to be running while the heater is on, ours has a 35 foot vertical stack so we don't need a fan to assist, but since you it sounds like you have a horizontal run you likely need it. It is plumbed or piped the whole way out of the basement though the crawl space correct?

Another trick is to open a basement window to allow fresh air to come in. When the pool heater is running it is dumping a LOT of hot exhaust air outside and unless it has an easy source for make up air or fresh air it can back draft or just exhaust slowly allowing some to stay in the basement and crawl space.

I would strongly recommend putting a CO2 detector in the basement, although not right next to the heater or it will go off a lot, but in the nearest living space and not in the pool room. Having said that a working heater should not make CO2, just a lot of heat and water (humidity), but should definitely be vented outside.

Being as how the basement and the crawlspace are steamy me thinks you have leaks in the exhaust system. As Brock said you need to provide enough unrestricted combustion air. Still sounds like something is leaking. Water vapor is a product of combustion. I'd go over the exhaust things visually, very carefully, looking for deteriorated pipes, holes, bad joints etc. Something isn't right. Does the smell in the basement and/or crawlspace smell like combustion products? Don't know how to describe it but it's a strange odor. Until you get the issue corrected I certainly wouldn't run the heater. CO is insidious and is a common cause of death. When troubleshooting this system when it's fired up I'd make sure someone else is around just in case. Brock is also right on about a CO detector. Anytime there are combustion products in the home, you need one.
Al
If anyone needs reinforcement on the smoke/CO detector issues....about 3 weeks ago we lost two girls in their 20's and 3 kids in a house fire here in Podunkville (Honesdale), PA. One smoke detector went off after the fire was out. In a drawer. Others were not working. Previous fire death here was 10 years ago.

You might be able to install the heater out doors depending on your plumbing set up. Another option depending on how close you can put the heater to an outside wall is to install a Jandy Hi-E2. it can take air from the outside and return it to the outside with its own internal fan as long as the run is not to long.

There was no noticeable "odor" in the basement. Actually, at first I thought the clothes dryer vent was leaking because that is what it felt like, moist air. yes, we have a horizontal run going from the heater, through crawl space, to the outside..right before it gets to the outside wall, there is a small fan of some type...i assume it helps push things out..will have to look at that again (saw it a while ago when moving in 6 mos ago, just now getting pool going). I have been doing some reading, and I read about a two-pipe system, which we may have. There is another duct run, and the one end of it sits right next to..kind of just above, the heater..could not figure out its purpose before. The other end just kind of stops in teh crawl space..is this one supposed to bring in "fresh" air for the heater to use? It has a baffle in it too..to control air flow. Thanks for all replies thus far. FYI, we have a CO2 detector on the main level (our house is a two-story w/ basement). The basement, right now anyway, is for storage, laundry, heater, hot water tank. Will probably finish a portion of it at some point. I tried to attach a pic, but this site will not let me upload it (too big), will have to figure out how to take a smaller size pic.

attached is the pic. The wall w/ the heater outlet is the bottom of the crawl space. Just above the wall is the entrance to the crawl space where both ducts head to (w/ the one going outside). commments?

bump, bump, bump

That looks good. I think you need to find out how that exhaust fan is controlled and make sure it is running when ever the heater is running since you have some horizontal runs.

Was finally able to take a closer look at that exhaust fan. First off, I have a Sta-Rite heater. Second, the fan is either broken or not wired correctly. It does not turn on. It has its own switch, plus it seems to be wired back to the heater...I am guessing this allows it to kick on only when the heater is on. Third, after the exhaust fan, the ductwork is not totally connected...looks like a screw is missing. So, I am calling in a professional to take a look at the whole thing and to replace/fix the fan. All of the plumbing for this pool goes straight through the block in my basement...so putting the heater outside would probably require a ton more work than is necessary.