Exhaust smell from Heater

[Kjp300]

When my Hayward heater is burning, I notice an exhaust smell. Kind of hard to describe, but it has a strong smell of burning gas. Kind of like when your gas oven first ignites you can smell the burning gas, then it goes away. However, this exhaust smell does not go away. It does not smell like burning leaves or plastic, or of any material burning.

I checked all of the lines for gas leaks and there were none, and there is no smell when the heater is off. The smell is definitely from the exhaust. The heater goes through its self check and ignites ok, and the pool seems to be heating normally, at about 1-1.5 degrees per hour.

Is some smell normal? I didn't notice it last year, but then again I really wasn't looking or it. I will probably call a technician out just to make sure it is operating normally, but just curious if some smell is normal. Thanks!

 

[wireform]

When its running get a look at the burners to see if all the have a flame. Have seen this once where a burner wasn't lit and others were. The tube was off the orifice where the gas goes into the tube so no flame.

 

[Kjp300]

Thanks. I will check that out.

 

[Kjp300]

Dug out my manual for the heater today. Haven't had a chance to take the heater apart, the weather is too bad. However, I noticed that Hayward recommends a calcium level of at least 200ppm. Since I have a vinyl liner pool I have not been concerned with the calcium level and mine has remained consistent at 125ppm. The manual says a low level is corrosive the the heat exchanger. The heater is 3 years old. Should I raise the calcium in the pool, or not worry about it? Thanks!

 

[Kjp300]

I had my neighbor look at my heater, and he thinks it is a gas smell coming from the exhaust when the heater is operating. He owns a commercial HVAC company. Admittedly, he does not have experience with pool heaters, but he understands furnaces, gas lines, pressures, etc. Stuff that is way out of my league.

He believes that all of the gas is not burning when the heater is on and some of it is escaping from the exhaust. Like wireform suggested, he wanted to see if all of the burners were lit and look at the color of the flame, but quickly found out you cannot visually look at the burners in this unit. He showed me where the burners were, and suggested that I can remove the front part and clean out the tubes that lead into the burner to make sure the burners are all getting gas. I think I can manage that. Unfortunately, he left town today for a job and will not be back until the weekend. He said will help me do further testing then.

I checked online, and there are some old threads that showed the same problem. Any obvious solutions? Does this make sense, are we on the right track? I read a couple of threads on heaters, and most of the jargon is out of my league, but I am sure he would understand it and have the tools to test the unit properly. Any suggestions from the experts on what he should look for and test?

Thanks for any suggestions or comments.

 

[swamprat69]

An odor in the exhaust gas that is not a raw gas odor and is somewhat difficult to describe but that can be slightly irritating to the nose is usually indicative of incomplete combustion. Should remove burner tray and clean manifold orifices with a pipe cleaner and inside of burners with a burner brush and slots in burners with a wire brush then blow out burners with compressed air or CO2. At the same time check for obstructions to flow through the heat exchanger.

 

[wireform]

I concur with what he said. Remove the burner tubes and make sure to rid them of spiderwebs including the nozzle on the main pipe that feeds the burner tube.

 

[dmk]

FWIW I have an MasterTemp 400 and it also has a very distinct exhaust smell. Every so often the wind shifts and I get a whiff from my patio. Doesn’t smell like gas, though if you are standing near it when it fires sometimes there’s a brief gas odor.

I assumed it was normal. These things burn a ton of gas.

 

[Kjp300]

Thanks for all of the replies. It seems we are on the right path and need to clean the orifices and the burners. I will try that and see if it works.

 

[Kjp300]

Had a chance to take out the orrifice assembly today. One of the orrifices had a spider web in it. I cleaned out the orrifices, reassembled, fired the heater back up. No gas smell. Burning clean.

The whole job took about an hour. The hardest part was loosening the gas line union. Never thought I would get that sucker to move. Thanks TFP! Before TFP that would have definitely been a call to a service tech and probably a $200 bill.

 

[markayash]

My Hayward has always had a bad smell since it was new. I even place a small fan blowing the exhaust away from the pool when in use. It also does have a raw gas smell when it first kicks on.

 

[Kjp300]

You may want to try to clean the orrifices. The smell I had coming from the exhaust is definitely gone.

 

[jandersen13]

Hi @Kjp300 - I think I have exactly this problem with my Hayward heater. Actually just created another thread and then found this. Would you be able to direct me to how you cleaned yours out? Have a picture handy of where, etc?

 

[Kjp300]

Hi @jandersen13 . Sorry haven’t been on for a while. If you haven’t fixed it yet I will try to guide you through it. I am not very handy so if I can do it you can too. I am also not a tech guy so I will show pictures but I cannot edit them with arrows etc.

You have to remove the burner assembly which is not very difficult. Open the front panel to the heater and you will see the burner assembly. Mine is 200k BTU so it is attached with 4 screws. The burner assembly is the black tube.


Once you remove the screws remove the two wires you see attached to the regulator. At least that is what I think it is.

Then you will have to remove the Union connecting the gas line to the heater. I attached a picture of my plumbing. To loosen the Union on mine I had to turn it to the right which is the opposite of what you would think. I was trying to turn it to the left and it wouldn’t budge. My neighbor who is an HVAC guy helped me here and set me straight.

At this point you should be able to remove the assemble. Once the assembly is out use a wrench to remove the orrifices. I cleaned mine with a pipe cleaner. Only one was clogged with spider webs. But once cleared that did the trick.

I hope this helps. I did find my Owners Manual online at the Hayward website and that helped a lot.
It has been a while since I did it but I think this is it. Mods feel free to expand upon the explanation if necessary.

 

[Vickery]

Your experience is not unusual. There is a spider called -what else?- "orifice spider". They inhabit both gas and lp grills and in your case the pool heater. You were likely smelling the mercaptan that wasn't completely burned. Not unusual either but it does give you an indication that something isn't quite right. Congrats on repairing it yourself. And I'm sure you did save a ton of money.