The Right Secondary/Cont. Run Blower for a Keystoker Boiler

What is the most economical, but correct continuous run secondary/auxilary blower for a Keystoker boiler? I inherited a house with a Keystoker boiler and it has a continuous run blower. It has died. Now I am having a hard time keeping the temp from creeping up too high (220+). I have to keep an eye on it and bleed out hot water and put in cold behind it when I see it starting to inch up. Sometimes I don't find it until it's already over 200. I am able to keep the fire going with the timer, but can't keep the temp steady around 180. Also, the coal is not burning nearly as thoroughly. The ash tub is much heavier now. I want to get this squared away before winter. thanks, fellas (and ladies?). I had none of these problems when the continuous run blower was working, so I need to get it back. I don't know much about all this. Like I said, I inherited this house and this Keystoker boiler. I'm pretty clueless.

unity,

Welcome to the forum! This sounds like a puzzle? The continuous run combustion blower is a newer item on a Keystoker. Previouse Keystokers ran just fine without it, they added it now to give a more complete burn, less black in the ash. I can't think of a way that this little blower failing would make your boiler temp go up? It shouldn't effect it. To me this sounds more like an acqastat problem.

That being said;

What feed rate setting do you have?

What timer settings do you have?

-Don

Don, Thanks for putting up with my ignorance. As far as the feed rate, I can only tell you that according to the number of turns of the nut on the feed control arm - 11. As far as the timer settings, since the little blower stopped I have, through trial and error, arrived at the following settings to keep the fire from going out during this summer: every 5 minutes for 30 sec. and 1 minute alternating. When I began to find it overheating, I tried all different combinations of less often and for more or less duration, but I arrived at this to keep it from going out. And it will go 3, 4, 5 days right dead on 180 at 12 psi, but then it begins to creep up and I do the bleed hot water/input cold. If I don't, it will keep creeping up. Sometimes like today, I found it at 220 when the last time I checked it two days ago it was on a 5 day run right at 180.

This is from the Keystoker bolier manual:

To obtain a more complete burn out of coal, a small secondary blower motor was attached to the stoker unit. THIS MOTOR IS DESIGNED FOR
CONTINUOUS RUN.
When large stoker motor is running on demand, small blower will assist with combustion and heat output, by producing a more intense and hotter fire. When demand cycle is completed,large stoker motor will shut off, and small secondary motor will continue to run. This will cause the coal that is already on the grate to burn, rather than to allow coal to smolder and die out in an unburned condition. This will achieve a cleaner ash, and allow more heat to be produced and absorbed into heating system.
During summer operation, the small combustion motor will force a small amount of air through grates at all times, which will cause the ash to become like powder. It also prevents the fire from going out. At the same time, it reduces the size of fire bed to approximately 1 ½” to 2” which will prevent boiler water from becoming overheated.

I thought maybe this was why I only started having this overheating problem when the little blower died. Now the fire is way down on the end of the pan, almost to the edge. Before it was a nice 6" stripe up in the middle of the pan.

So, what is the right little blower and where can it be purchased at the best price?

Fasco No. 7021-2366
Model B30
45cfm
1/70 hp
3200rpm
TypeU21

https://www.emotorstore.com/productdetail.asp_Q_c ... ID_E_33494

http://www.electricmotorwarehouse.com/fasco/B30_dim.jpg
******************************************************************************************************
http://www.electricmotorwarehouse.com/PDF/1TDN5_specs.pdf
1TDN5 53 CFM 3388 RPM 115 Volts 60/50hz
Old # 4C012
Specification Sheet .30 B30 7021-3486 4 lbs. $58.84

You can and should replace the blower, as McGiever discribed but, if you are making a large enough fire to get all the way down to the end of the grate, just to heat DHW in the summer, something else is wrong. I'm not an expert on this stuff but, it sounds like every once in a while the aquastat sticks ON causing the feeder to run more than it should, or the timer? Bottom line, you shouldn't get a full grate of burning coal heating DHW in the summer, maybe if you have 8 teenagers taking showers.

Also, if your boiler is maintaining 180 degrees, when it's running normaly, you should consider adjusting the aquastat to 140 ON and 160 OFF. you don't need 180 degree water to heat DHW.

This is all asuming domestic hot water is all you are heating and not something else? If you are heating a zone, the pump could be failing causing a call for heat to not be satisfied. That would make the boiler temp go up.

First, take a look at the aquastat!

-Don

Also, if you are heating DHW an easy way to cool down the boiler is turn on a few hot water taps full blast. This will bring cool water through the DHW coil cooling the boiler. Venting boiler water and filling with new water is realy bad for your boiler, it will cause boiler shock and rust from fresh water.

Don

Oh, and this is what an aquastat looks like.
You just move the pointers to the temp you want.

-Don

This whole thread seems to be confirming points discussed in another recent thread. The feed setting used with a secondary blower runs coal off the end of the grate when the secondary blower fails, and the secondary blower provides the "benefit" of cooling the boiler by blowing unneeded air through dead ash.

"Don't it always seem to go that you don't know what you've got 'til it's gone..." . OK, so Joni Mitchell probably doesn't get quoted that often in a coal forum...

I'd go with StokerDon's observation that these stokers worked pretty well for a long time without secondary blowers. One option would be to cover the hole and adjust the settings so it it is tuned to run without the secondary blower. You'd use less coal and put less waste heat up the chimney, but I guess that's the price you'd have to pay to go to the old school.

Mike

Your boiler is overheating because the timer is running the stoker too often, and your feed rate is higher than necessary for summer operation. Set the feed at 15 turns from max, and reset the timer to 1 minute every 15 minutes.

Do you have a dump zone setup?

Unity,

You keep saying you let hot water out and add cold water. If, by that you mean you are letting heated water out of the boilers water jacket and re filling with fresh water, you may want to stop. Not only is it dangerous, its not good for the boiler to keep adding fresh water because it will add a lot of air to the system as well. As someone else mentioned, if you have a domestic coil running hot tap water is a quick way to shed some heat. And the dump zone Rob mentioned is very important.

I don't know what a dump zone set up is , although now I know that whatever it is it's very important!
When I let hot water out I do so by opening the valve on the expansion tank to which is attached a hose. I open that valve, the hot water starts flowing out into the driveway and I open the water input to the stoker and what until the blower kicks on (not from the timer). It usuall takes about 10 min. After that the temp will be at 180 (aquastat is set at 170) and stay there for 4-5 days before it starts to creep up again. Perhaps it goes up because it a windy day and the draft increases, thereby causing the fire to get hotter and the temp to go up? :surrender:

I understand the idea that the coal fire at the end of the pan with the upper part of the pan being unburned coal indicates too much coal being fed when the timer turns the blower/feeder on every 5 minutes (for 30 sec. and 1 minute alternating). I have tried having the timer come on less ofter and for less duration and reducing the feed. I have tried different combination and the fire always ends up going out (without the little blower). I don;t know if among all the combinations I tried has been setting the feed at 15 turns from max, and the timer to 1 minute every 15 minutes. I'll try it, I'm just afraid the fire will go out with the blower coming on only every 15 min., but what do I know! I'll try it. The worst that can happen is that I'll have to restart the fire 9no doubt in the middle of the night!). We have two apartments as part of our house, so the tennants need to have their hot water. If the fire goes out, I have to get it going again ASAP. :whip:

A dump zone is some form of heat emitter that is used to remove heat from the boiler. A lot of people just use their main heating loop. The keystoke should have come with an aquastat to be used specifically for this. What controls do you have on this boiler? can you get soke pictures? The over temp aquastat closes on a tempature rise and this is usually tied to the tt terminals of the boilers main aquastat. This causes the circulator to run and will lower the boiler water temperature safely. For the good of your boiler, do not continue to lower the temperature the way you have been.

Here are some pics, for what they're worth.

Unity, don't worry, We will get this figured out. It could be that you just need to get the correct adjustments dialed in. Remember, you can't make large adjustments on a coal stoker. You make small adjustments and observe how the fire changes over the coarse of an hour, or more. A coal fire changes very slowly, not like a wood fire or an oil fire. The Kestoker boiler is a wonderful machine and there are many members here that have run them for decades with only simple maintinance.

So, I'm assuming everything was OK until the little blower died. Since there is now combustion air only during a timer cycle or a call for heat, the timer cycle would need to be increaced in time or frequency to maintain a fire. That should be a slight adjustment like going from 30 sec every 15 min TO 1 min every 15 min, or maybe 30 sec every 10 min.

One other thing that can cause the fire to go out is poor chimney draft. If you don't have a manometer to monitor chimney draft at least make sure the barometric dampner isn't hanging open. The other thing to check for as far as draft goes is the stove pipe leading to the chimney. The last winter was very harsh, making everyone's stoker work very hard. This causes more fly ash to accumulate in the stove pipe that normal. If you have not pulled of you stove pipe from the boiler to the chimney off and cleaned it out in the past 6 months, I bet it's FULL of ash. Get that out of there and things will improve greatly.

-Don

Thank you for the pictures, that helps a lot. I can see some stove pipe issues. That long horizonal run out of the boiler is a trap for fly ash, I would bet that pipe holds a good 15 pounds of ash. The other thing is all that foil tape. it may be time to replace some stove pipe.

-Don