Raypak Heater 266 wasted heat

[guytimes]

Hey all, I have a Raypak Heater 266 (natural gas) on my new (saltwater) pool build. I have the heater located in my pool shed, along with the plumbing. Since the heater is located in a shed, the pool installer said I needed the vent blower kit and need to vent it out the roof of the shed. He said I need to hire someone to do it, or, DIY if I know what I'm doing. From what I understand, the 4" output needs to be positioned inside another duct, as a heat shield.

I hooked up the electric myself and paid a plumber to hook up the gas line. It works great and raises the temp about 2.3 degrees per hour. I have a couple questions:

1. Do gas heaters work more efficiently at a low flow rate or a higher flow rate? My Chlorine generator catches the water temp as it's leaving the heater and the temp of the water leaving the heater (on the lowest flow setting) is about 10 degrees warmer. On a higher flow rate the temp shows about 6 degrees warmer, but of course the water is moving faster. So I'm thinking the higher flow rate is more efficient?

2. The 4" pipe gets so hot you can't touch it. The air blowing out of the vent is hot like a hair dryer (or hotter). It pains me to see this hot air going to waste, when it could also be heating my water. I realize the air has carbon monoxide so I need to be careful. So my question is, has anyone invented any kind of mechanism to re-capture this heat and use it again? For example, maybe a box on the roof of the shed with copper coiled pipe? Hmmm I donno.

 

[jblizzle]

1. Generally things are more efficient at higher flow rates as more heat can be added by adding a couple degrees to a lot of water than a lot of degrees to less water.

2. All this is true. There is always waste heat and you need to be careful with that exhaust. I am not aware of a commercial system to capture the exhaust heat, but it is certainly possible ... just not sure it is cost effective.

 

[danpik]

Yes, they are called condensing furnaces. The pool heater industry has not caught up with this technology I don't think. When these furnaces/boilers draw the excess heat out of the exhaust stream, it causes an enormous amount of condensation to occur. This is due to the large amount of water vapor present in the exhaust gas. The temp of the exhaust gas must stay roughly above 150 deg F for the water vapor to not condense out. Trying to capture the excess heat from the flue would only create a large amount of condensation to drain back into the unit.

The way that unit is vented now (assuming into an enclosed bldg.) it would get red tagged here and the gas meter locked until it is fixed properly. The proper way to vent that is with "B" vent pipe (Double wall pipe) so the gas does not cool too much and also to have a properly designed chimney thru the roof or sidewall.

 

[ps0303]

Yeah red tagged here as well. The gas installer shouldn't have hooked it up unless it was properly vented.

Please don't run the heater until you get it vented properly.

Pools heaters are not like gas fired high efficiency furnaces. This industry isn't like that.

 

[BoDarville]

All of the previous responders have given you good information. If heater is located in an enclosed shed, it should be vented through the roof with a properly designed chimney.

At my previous house, I had one of those high-efficiency (90+%) natural gas condensing furnaces installed. It was one of the first central furnaces of that type. The exhaust design & material had to be tweaked several times because so much condensation was draining back into the unit that it kept shutting off. Eventually got those kinks worked out. Hopefully, the latest models are more refined and the exhaust principles more well-understood so those problems should not occur.

Keep in mind that not all of the rated BTU's of a gas-fired pool heater will go towards heating the water. As you have experienced, some of that heat is lost through exhaust. If you cannot find the efficiency rating of your pool heater on the label or in the documentation, a rough approximation of the efficiency (e.g., actual BTU's that go toward heating the water) would be 75-80% of the rated, or gross, BTU's.

 

[guytimes]

Ok, so we all pool our resources and invent a condenser for gas pool heaters! ha ha.

I guess I'll just accept the fact that I'm wasting a ton of heat. It seems sooo inefficient but that's how it goes.

I have my hvac guy coming this week to properly vent it.

 

[BoDarville]

Even with some of the heat being lost to exhaust, properly-functioning gas heaters burn cleanly and are still the quickest way to heat the water for a specific event such as a pool party. Of course, "quick" is a relative term when it comes to heating pool water.

 

[guytimes]

Hey all, just wanted to follow up. You will be happy to know the B-vent got installed and is functioning. Even with the double wall pipe, the outside pipe is still really hot!

My installer said he guarantees that if the inspector finds a problem with it, he will fix it or make it right. He had to cut part of my shelf away. I wanted him to just make a small cut-away in the shelf but he said he didn't want to take a risk of someone putting something on the shelf and it leaning against the pipe and starting a fire. Makes sense. I'm happy with the turn out.

Look ok to you guys?

 

[ps0303]

Looks like he did good. I agree with he reasoning on the shelf cut away. Better to be safe.

 

[daleyfolk]

Glad you got that vented! I just had a 266k has heater put in this spring. My installers were so cautious, they didn't even want to put the heater (outside) under the eaves (8 feet above the heater) and only about a one foot overhang.

Wasn't your pool shed unbearably hot?