Combustion Fumes from OM-148

[ak99588]

We just installed a new Toyo OM-148 water heater and it works great except we are getting combustion fumes every time it fires. The fumes are gone quickly after it shuts down, but always come back when it starts up again. The unit is brand new. We also installed new vent pipes and swept out the flue chimney, so definitely no blockages or issues with the vent hardware itself. No other appliances are running when it fires, and the boiler is shut down. I included a picture if that will help. Do I need more combustion air or does the unit need to be adjusted? We live in Copper Center, Alaska. Thanks!

 

[IFIXH20]

Did you install a barometic draft regulator and a flue/chimney liner ?

 

[ak99588]

Did you install a barometic draft regulator and a flue/chimney liner ?

Yes, just above the photograph on the vent pipe is a 5" barometric regulator. We did not install a flue/chimney liner (not sure what it is), we just fastened the new flue right to the existing chimney. When I get home later I will post pictures.

 

[IFIXH20]

The chimney may need a flue liner to reduce the amount space for combustion to draft better. After the chimney was sweep did the sweeper inspect the chimney for loose motar or liner ?

 

[IFIXH20]

A flue liner looks like a dryer vent. The flue liner is placed in the chimney and connect directly to the systems flue pipe.

 

[ak99588]

A flue liner looks like a dryer vent. The flue liner is placed in the chimney and connect directly to the systems flue pipe.

No flue liner when we started, and no we did not install one. The installer did not mention it. He suggested we are getting down drafts because the weather just changed from cold to warm and house pressure is going negative. Most windows are open during the day when this is happening, and the room where these are located is wide open so I would think that the house and outside pressure are the same. If negative pressure is the problem what can be done?

 

[ak99588]

Here are the additional photos I promised earlier. You can see the entire vent system up to the chimney.

 

[IFIXH20]

The flue pipes at the ceiling need to be sealed ( should have used a proper reducer). You could be getting a back draft at the unsealed flue at the ceiling. Some of those system only require a total length of 25ft of flue, each elbow can account for 3ft to 5ft. You should call a contractor out to find and fix the problem , which i think is a professional fix. The fumes could be deadly ( combustion = carbon monoxide)

 

[Caduceus]

It's also important to get an opinion as to whether or not the "combustion fumes" may just be a result of the new appliance and the flu piping getting hot for the first time and residue from manufacturing is burning off. This happens sometimes with new appliances until they are used for a while. We can't be sure exactly what it is without being there, so have it checked and let us know what is found.

 

[ak99588]

The flue pipes at the ceiling need to be sealed ( should have used a proper reducer). You could be getting a back draft at the unsealed flue at the ceiling. Some of those system only require a total length of 25ft of flue, each elbow can account for 3ft to 5ft. You should call a contractor out to find and fix the problem , which i think is a professional fix. The fumes could be deadly ( combustion = carbon monoxide)

Unfortunately we are in a remote area and the closest contractors are 140 miles away. They don't tend to come out here unless they have multiple jobs or a big project, so we have to do most jobs ourselves. Will metal foil tape to the job of sealing the pipes?

 

[IFIXH20]

Unfortunately we are in a remote area and the closest contractors are 140 miles away. They don't tend to come out here unless they have multiple jobs or a big project, so we have to do most jobs ourselves. Will metal foil tape to the job of sealing the pipes?

I sure hope you have carbon monoxide detectors. Foil tape will ONLY be a temp repair for a seal ( you need the proper reducer), when the adhesive wears off the tape will fall from the flue pipe. If you can't get a contractor out you should try the manufacturer.

 

[IFIXH20]

It's also important to get an opinion as to whether or not the "combustion fumes" may just be a result of the new appliance and the flu piping getting hot for the first time and residue from manufacturing is burning off. This happens sometimes with new appliances until they are used for a while. We can't be sure exactly what it is without being there, so have it checked and let us know what is found.

You make a good point. Manufacturer do put a oil base coating over the heat exchanger and burners to prevent rust during shipping and storage. This sometimes do give off a very bad odor.

 

[ak99588]

We do have CO detectors in the house and they are not going off. Regarding the reducer, where do you see that is needed? We have a 7" chimney and the pipe coming off the boiler is 7". The flue from the water heater is 5" which we have teed into the 7" pipe. Not sure where a reducer comes into play in the system. Which manufacturer are you referring to, Toyo or the vent pipe? I'm just not sure what you are getting at when you talk about sealing the flue.

 

[chukar]

Just throwing this out there one way to help make sure your drafting correctly is to use a lighter put it near each joint as well as the damper, it should be a neutral flame if its sealed proper, if the flame gets sucked in like near a damper that's also ok, but if its getting pushed away you have an issue, instead of foil tape consider using a product like FS1 made by hilti, it's an high temp silicone.

You can order on amazon a CO detector off amazon if you really want to do it all your self, once again put it up to every joint and test.

 

[IFIXH20]

We do have CO detectors in the house and they are not going off. Regarding the reducer, where do you see that is needed? We have a 7" chimney and the pipe coming off the boiler is 7". The flue from the water heater is 5" which we have teed into the 7" pipe. Not sure where a reducer comes into play in the system. Which manufacturer are you referring to, Toyo or the vent pipe? I'm just not sure what you are getting at when you talk about sealing the flue.

In the last pic that you posted there seem to be a gap where the 90(elbow) is attach to the flue coming out of the ceiling (this is the point that should be sealed), The 90 seem to be too far inside the flue pipe. The flue coming out of the ceiling is more than likely double wall pipe and something just don't look right, it appears that the 90 is placed inside a larger flue pipe and held in place with screws.