Radiators Are Not Hot

I have the thermostat in the upstairs zone cranked at 75F and the thermostat temp in that zone, which includes a loft, is at 63F. The basement loop is set to 80F and the temp is reading 74F. With the oil boiler, the house would get warm rather quickly and the baseboard radiators would be hot to the touch. Now with coal supplying the heat, the radiators are just warm. I've bled them a lot and there doesn't seem to be any more air trapped in the system.

The pressure on the coal is at 17-18 (which is the norm here)
and the temp in the boiler is currently 165F.

The stoker is pushing coal at the moment because I assume the thermostats are calling for heat and the boiler is making it.

Does a coal boiler take longer than an oil fired one to get the zones satisfied or could something else be wrong?

thanks.

Coal takes time, it can take 30min to an hour+ or so to start getting more heat out of stoves or boilers. Patience is the key. Oil/Gas can fire right up and start heating immediately.

Ok. I increased the Hi/Lo limits to 190/170 and the pipes up in the loft finally got hot.

This poses the question of the use of digital thermostats and having them set at different temps during the day. With the oil, I would have the upstairs one set to come on at 4:30am and heat the house for when I got out of bed. It then went back down around 8:00am and stayed at 63 until about 5:00pm when it turn back on and heat the house for when I got home at 6:00pm.

Sounds like with coal that it would be better for it to be at a constant temp?

Hollyfield,
I'm coming to that same conclusion. I used to swing my setbacks from 65 to 70 with oil. I just reprogrammed them to swing from 69 to 72. It was taking quite a while longer for the house to get up to temp in the morning and evening. The boiler ran almost two hours straight this morning satisfying the bump up. I'm working out of the house today so I get to monitor the system. It might actually be more fuel efficient and comfortable keeping the temps close to the same. I'm giving it a try to see what happens.

Keep in mind, that while coal takes longer "to get there", it also takes longer to come down. If you have enough increments on your programmable T-stat, you might want to try bringing the temp up in increments, so that it gets an earlier start, and also so it doesn't overshoot.

I went out for a little while and left the thermos where they were. I get home and the dogs are panting and it's summertime in my house.

WNY wrote:Coal takes time, it can take 30min to an hour+ or so to start getting more heat out of stoves or boilers. Patience is the key.

Words of wisdom.

I increased the Hi/Lo limits to 190/170 and the pipes up in the loft finally got hot.

About 30 minutes ago I noticed that the boiler was past 200 and getting very close to 210.

I opened the zone valves to help cool it down and its now back around 180. I have the downstairs thermostat off and the one upstairs at 65F. I dialed the Hi/Lo back to 160/180 and turned the red nut from 11to 15.

I am not going to tweak it anymore until tomorrow. I'll check and record the temp at times but that's it.

WNY wrote:Patience is the key.

i haven't changed anything on the boiler and the temp is at 195F at the moment. Circulator is off and no zones calling for heat.

In your first post, you said your boiler was at 165*, but your radiators were cold.. are your radiators in series or parallel with a common pipe?? If in series, you should have had the first radiators in each zone at the same 165*, but the radiators would get progressively cooler as the water loses heat to each radiator..

Do you have a way to measure the water temp in the return line from the zones??

Greg L.

It's common for a coal boiler to overide it's temps a bit. If you set the high limit to 180, it stokes until it hits 180. If at that moment, the house is satisfied, you have a lot of coal that has been introduced that will continue to burn. Until it finishes burning the water temps will continue to rise. It's no problem at all unless it hits 230. Make sure your pressure relief is pointed down to the floor. I don't think you have a problem, you just have a case of the newbies....kinda like me. I saw my boiler hit 210 & was going "what do I do? What do I do?" The answer is... go have a sandwich.

just a side note I've seen 265F on windy nights in my AA260 becuase the draft was too high. I keep my draft around .02-.04 if it gets above .05 then it starts to draw thru the coal bed burning like a stove and on my chimney I've seen as high as .17 before. pretty much I have no concern about my boiler setting at 230-240 for short periods till the next call for heat. If you get a boiler control with the post purge feature it helps to control over rides by running after the call for heat has ended and the boiler shuts down to move the heating water out into the zone and cool water back into the boiler to take up the heat till the coal cools down a bit

LsFarm wrote:In your first post, you said your boiler was at 165*, but your radiators were cold.. are your radiators in series or parallel with a common pipe?? If in series, you should have had the first radiators in each zone at the same 165*, but the radiators would get progressively cooler as the water loses heat to each radiator..

Do you have a way to measure the water temp in the return line from the zones??

Greg L.

The rads are in series with the furthest one away being 2 floors up in the loft. It just took time for the rads to heat up and shake off the cold. Also being a newbie to coal, I wanted heat now to see how it worked and like I've learned, patience is key.

All has been good now and the house is warm (although its not that cold outside yet)

Freddy wrote:It's common for a coal boiler to overide it's temps a bit. If you set the high limit to 180, it stokes until it hits 180. If at that moment, the house is satisfied, you have a lot of coal that has been introduced that will continue to burn. Until it finishes burning the water temps will continue to rise. It's no problem at all unless it hits 230. Make sure your pressure relief is pointed down to the floor. I don't think you have a problem, you just have a case of the newbies....kinda like me. I saw my boiler hit 210 & was going "what do I do? What do I do?" The answer is... go have a sandwich.

I hear ya, Freddy. There is certainly a lot of learning and settling the nerves when using coal for the first time. Now that I have it dialed in (for the most part), I'm starting to relax and only check the boiler and the fire 3-4 times a day instead of almost every hour.