Question for those with thermostatic air control

[mranum]

Had some issues with the old thermostat no longer working as it should, I put on a new replacement. While staying around the burner for a long time and adjusting the thermostat I noticed something odd. When you load, then it gets up to temp and shuts the air off it will do a "burp" of smoke from the draft and the door about every minute or so until the burn settles down. I have a thermo on the flue and the air gets shut when it hits about 500* then will settle down and burn around 400*.

Now, not having had a lot of experience with this particular stove I am wondering if the draft flapper closes off to much air? Should it close completely or have a slight gap? It does have about 1/16" of an inch gap in it now. The pipes and chimney are clear, I just swept it this morning and the wood is split oak and stacked under a roof for 2 years.

The stove is a 1978 Riteway #37.

Open for opinions.

 

[Battenkiller]

Had some issues with the old thermostat no longer working as it should, I put on a new replacement. While staying around the burner for a long time and adjusting the thermostat I noticed something odd. When you load, then it gets up to temp and shuts the air off it will do a "burp" of smoke from the draft and the door about every minute or so until the burn settles down. I have a thermo on the flue and the air gets shut when it hits about 500* then will settle down and burn around 400*.

Now, not having had a lot of experience with this particular stove I am wondering if the draft flapper closes off to much air? Should it close completely or have a slight gap? It does have about 1/16" of an inch gap in it now. The pipes and chimney are clear, I just swept it this morning and the wood is split oak and stacked under a roof for 2 years.

The stove is a 1978 Riteway #37.

Those were supposed to be pretty cool stoves. They were well ahead of their time. Many of them were tested back in the 70s as having very good combustion efficiency for back then, with long, steady high heat output as well.

Best I can tell is that you seem to have a handle on the cause of the problem. You're getting backpuffing from the temporary stopping of air and the stove filling up with smoke. The velocity of the air inside the flue slows down with the stove closed, which allows air to come down the flue and then the stuff lights off. Poof! Little explosion. Since the inside of the stove is now pressurized a bit, the smoke is forced out the air inlet and the gaskets. Then the magnet on the draft flap pulls it back closed the next instant. It must be annoying, but I can't think of a way to defeat the problem because of the thermostatic control over the burn. Maybe someone else will come along with an idea that will help.

 

[Peter B.]

Some thoughts at large... none of which may be of any use.

A friend of mine bought a Riteway new in '76 and burned it for many years. He may (or may not) have overfired it numerous times, but by some point in the '90's, the secondary combustion chamber had burned and warped to the point that the stove had lost most of its efficiency. You might inspect the secondary chamber for damage before you put a lot more time or money into the stove. I wouldn't expect the stove's performance to be to spec if the secondary is burned out. It's fairly heavy steel, but time, heat and oxidation takes a toll.

With my own stove, the times I get backpuffing (as you described) are:

1) ... when I close the drafts on my (otherwise hardly air tight) stove on a hot fire and the stove 'breathes' in enough air through seams and crevices to ignite the smoke... creating a small explosion.

2) ... when I try for a long burn by loading up and closing down. The wood chars slowly, but reaches a point when it 'wants' to ignite... and poof.

I modified my own stove to supply a small amount of supplementary air at all times... and pretty much eliminated the backpuffing.

In direct response to your question, it's hard to say whether the flap closing completely on a hot fire would cause the backpuffing... or leaving a gap open rather than closing the flap completely. (As I recall, shortening or lengthening the flap chain would adjust this.) You may have the option of trying different temps for the flap closing as well (by rotating the thermostat control?).

Sorry I can't offer more.

Indeed, for its time, I think the Riteway was reasonably well respected for efficiency... and the use of a secondary system.

PB

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[mranum]

Thanks for the thoughts guys. This stove has been overfired numerous times during its life with some warped panels to show its battle scars. Its efficiency is not all that great anymore as it does tend to make quite a bit of soot in the chimney in a months time. I hadn't given the secondary chamber much thought but its worth looking into.

This stove is in my parents house and up until last year my Dad was always able to take care of it so the rest of us weren't all that familiar with its operation. We lost Dad this past summer and us kids are running it for my Mother now, hence the education. It is only a matter of time where we either replace it or just run the furnace. Time will tell.

I understand Hitzer makes what is thought to be a clone of this model and there is a dealer about an hour away so I'm thinking about taking a drive and checking them out. Anyone have any knowledge about them?