Losing efficiency

Losing efficiency

PostBy: prrgeo On: Thu Jan 23, 2014 3:36 pm

My Reading RSDB-06 hot air furnace is losing efficiency and can't keep up with the extreme cold here lately. It seems to me that the problem is that the cycles with the blower forcing air through the ducts are shorter than they used to be, so less heating for the house. Why? It is power vented and has had a fire going for about four months. Is the problem 1) buildup of ash within the furnace, reducing heat going to the plenum? 2)too much draft through the power vent, blowing useful heat outdoors? 3) air forced into the plenum by the blower fan, which is low on the cellar floor, too cold, cooling it too fast and shutting off the fan? 4) wrong settings or spread on the fan limit controller (although it used to work fine)? 5) just too darn cold right now? 6)none of the above? Any advice or experience would be appreciated. This is the sixth season with this unit.
prrgeo
 
Hot Air Coal Stoker Furnace: Reading RSDB-06 Susquehanna
Coal Size/Type: Rice

Re: Losing efficiency

PostBy: Lightning On: Thu Jan 23, 2014 3:58 pm

I take it you don't have ducted cold air return?

Welcome to the coolest forum on the internet. .. :D

You can try changing your blower settings. Any of those things you listed could contribute to the shorter cycles.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Losing efficiency

PostBy: mariohotshot On: Thu Jan 23, 2014 6:39 pm

Where do you have you settings on the fan limit controller? Maybe you need to readjust them.
mariohotshot
 
Stove/Furnace Make: keystoker
Stove/Furnace Model: 90


Re: Losing efficiency

PostBy: prrgeo On: Thu Jan 23, 2014 8:14 pm

Mariohotshot: Settings are 100-130. These are the factory settings - I have not changed them. George
prrgeo
 
Hot Air Coal Stoker Furnace: Reading RSDB-06 Susquehanna
Coal Size/Type: Rice

Re: Losing efficiency

PostBy: coaledsweat On: Thu Jan 23, 2014 8:20 pm

Maybe your stovepipe needs a good cleaning? It doesn't take a lot of ash in it to reduce output significantly.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

Re: Losing efficiency

PostBy: samhill On: Thu Jan 23, 2014 8:24 pm

How long is your vent pipe? I'd check to see if there was any flyash build-up, I can usually tell just by feeling the temp difference between the top & bottom of the horizontal run with my bare hand. With the low temps we have been having it will probably build up faster than normal.
samhill
 
Hot Air Coal Stoker Furnace: keystoker 160
Hand Fed Coal Stove: hitzer 75 in garage
Stove/Furnace Make: keystoker/hitzer
Stove/Furnace Model: koker 160/ hitzer 75

Re: Losing efficiency

PostBy: waldo lemieux On: Thu Jan 23, 2014 9:01 pm

Im thinking its time to clean the heat exchanger tubes . Sounds like build up to me....
waldo lemieux
 
Stove/Furnace Make: efm
Stove/Furnace Model: s-20

Re: Losing efficiency

PostBy: prrgeo On: Tue Jan 28, 2014 2:39 pm

Thanks to everyone for their suggestions. George
prrgeo
 
Hot Air Coal Stoker Furnace: Reading RSDB-06 Susquehanna
Coal Size/Type: Rice

Re: Losing efficiency

PostBy: titleist1 On: Tue Jan 28, 2014 3:14 pm

Sounds like it could be an 'all of the above' :)

After 4 months of burning, I'd say it's time to do a little maintenance and see what may be causing the issues...how many tons have you used so far?

since it would be the biggest safety issue, i'd start with checking the power vent and horizontal flue pipe for fly ash build up.

then check for ash build up inside the furnace impeding heat transfer.

after that see what your draft is reading to find out if you are sending heat out the flue

then check temps on stove and maybe adjust fan limit
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite