One or two outlets?

Will be putting my new key stoker in this summer. It has 2 outlets on top. I ordered a 3" outlet since that was what my old furnace had. It also has a 2nd outlet that is 2". Would it make sense to just use the 3" outlet or would that be dumb? I have a one pipe one main line setup. Thanks.

Welcome to the forum,

What model Keystoker is it? Is this a steam system, or hot water?

If it is steam, you will want to pipe it to provide nice, dry steam. The install manual should show piping requirements.

-Don

From memory I think a 3" single riser is considered adequate for about 140k btu/hr worth of steam. What model Keystoker do you have?

Some good reading on steam piping: https://www.peerlessboilers.com/wp-content/upload ... eSteam.pdf

clahring wrote: ↑

Sun. Jun. 07, 2020 12:44 pm

Will be putting my new key stoker in this summer. It has 2 outlets on top. I ordered a 3" outlet since that was what my old furnace had. It also has a 2nd outlet that is 2". Would it make sense to just use the 3" outlet or would that be dumb? I have a one pipe one main line setup. Thanks.

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The folks at the heating help forum said it was fine to use both tapping's to feed a drop header to make dry steam to feed your radiators. I would imagine that you could also connect both tapping's with 2 inch pipe 45 degree elbow and a Y 3 inch Y fitting with reducing bushings to make use of both tapping's to feed steam to the single riser.

You have a very old house if I remember correctly; If you have enough headroom its always best to install a 3 inch drop header so that you can have dry steam enter the header pipe at a faster rate to vent the air out of the header pipe and fill it with dry steam.

Does the steam boiler have a return tapping at the water line to let you drain the condensed water vapor back into the steam chest?

StokerDon wrote: ↑

Sun. Jun. 07, 2020 1:03 pm

Welcome to the forum,

What model Keystoker is it? Is this a steam system, or hot water?

If it is steam, you will want to pipe it to provide nice, dry steam. The install manual should show piping requirements.

-Don

I have a KC 10 steam boiler. The KC 8 was smaller BTU's than my old slant fin sectional boiler and the KC 10 is larger. I figured it would be better to be oversized than undersized. I had the slant fin for 40 years and just found out it was piped wrong. It had two risers that "T" in the middle and then went to the main. I guess that is a no no. There was no drop header.

Rob R. wrote: ↑

Sun. Jun. 07, 2020 1:10 pm

From memory I think a 3" single riser is considered adequate for about 140k btu/hr worth of steam. What model Keystoker do you have?

Some good reading on steam piping: https://www.peerlessboilers.com/wp-content/upload ... eSteam.pdf

KC10 but I think it is over sized since it puts out more BTU's than my old slant fin and I could get the house as hot as I wanted to with that one but I would have been under with the KC 8. The slant fin was piped wrong two risers were T'd together in the middle and then went to the main.

Your boiler should be sized against the amount of steam radiation you have installed. The old boiler may have been barely enough, or double what you need. I guess it is a moot point since you have already purchased the KC10.

I would see what the guys at Keystoker think about the outlet. Unlike modern boiler and gas boilers, your Keystoker has a large steam chest which will help produce dry steam.

According to Dan Holohan in his writing, when older steam boilers were rated/sized to heat a building they were all sized to heat a building with all the windows and doors open as they did not have insulation in them.

A smaller shorter drop header is better than no drop header as you will always have dry steam entering the main header pipe and your steam heat will rise that much faster in the home to all the radiators heating the home much faster and reducing the time the stoker runs.

You can tie in the 2 inch and 3 inch tapping's into the 3 inch drop header safely according to the folks at heating help and make plenty of dry steam a s long as the drop header can allow the steam condensate to cool and drain back to the boiler water level.

The 30 minute timer will benefit the boiler as it can run longer to keep the water in the steam chest hot and also avoid having the fire die out on you as well by having a total of 14 minutes of run time in 4 periods like mine where the fire will have no chance to create an out fire condition.

4 minutes at zero time

4 minutes at seven minutes

4 minutes at fifteen minutes

4 minutes at twenty two minutes

This is slightly longer than what my settings are for hot water heat with my kaa-4-1; but as you are making steam your boiler water temperatures will need to be higher.
The settings for the stoker feed will have to be adjusted for the initial firing(my stoker is set at 6 threads out) and then you can increase the feed rate when it gets colder if needed.

Also keep in mind that your coal stoker does not have a burn pot/tuyer/underfed coal feeding system and you will have an out fire if the hold fire timer does not keep the fire burning(our the power drops out for longer than 3 minutes as you do not have a large fire at all times as you would with a burn pot.

You may have to experiment a little with the hold fire times but when the heating season comes along the thermostat in the home will be calling the boiler for heat and overriding the hold fire timer as needed to keep the steam going and using dry steam will heat the home faster at all times.

You may be able to drop your steam pressure a little using dry steam as your boilers response time to provide heat will be shorter.

Please keep us up to date about your progress with steam boiler when you have time.