How low does your boiler temp drop when a zone is calling?

Re: How low does your boiler temp drop when a zone is calling?

PostBy: wilder11354 On: Sun Feb 12, 2012 10:45 am

curious as to what temp your maintaining in Garage? if garage is not used for working on something daily, or other use.. wouldn't a lower temp, steady feed keep the temp in boiler from drastically droping? continous flow, but at a reduced flow rate? just a thought.
wilder11354
 
Hand Fed Coal Boiler: Harman SF260
Coal Size/Type: nut or pea, anthracite
Other Heating: crown oil boiler, backup.if needed

Re: How low does your boiler temp drop when a zone is calling?

PostBy: chevymatt On: Sun Feb 12, 2012 1:06 pm

wilder11354 wrote:curious as to what temp your maintaining in Garage? if garage is not used for working on something daily, or other use.. wouldn't a lower temp, steady feed keep the temp in boiler from drastically droping? continous flow, but at a reduced flow rate? just a thought.



The temp in the garage is set at 48*. there is an apartment above the garage without much insulation after it flooded from a wrongly installed circ pump.

How would I slow down the flow rate? Would it burn up the pump?
chevymatt
 
Stoker Coal Boiler: AHS S260

Re: How low does your boiler temp drop when a zone is calling?

PostBy: Phil May On: Sun Feb 12, 2012 1:15 pm

What temp are you trying to maintain in garage. I try to keep the garage 50-55 degrees and the mixed water going to floor is 80-85 degrees. It still gives a shock to the system when it comes on because all the return water is 55 degrees. The only way to minimise this is to have constant circulation in primary loop. You will still see a drop but it has not caused me any problems. It is just one of the problems with slab heat. Why are you running a water heater in series with your boiler. Unless your boiler wont do the job I would shut it off or bypass it. A bypass loop will help by getting all the water up to temp when there is no call for circulation.
Phil May
 
Stoker Coal Boiler: EFM 700
Coal Size/Type: Buckwheat
Stove/Furnace Make: EFM
Stove/Furnace Model: 700


Re: How low does your boiler temp drop when a zone is calling?

PostBy: steamup On: Sun Feb 12, 2012 2:04 pm

Radiant floor zones, especially those imbedded in concrete need to be hydronically isolated from a standard boiler system. IE-primary secondary with proper mixing control.

Slabs are especially difficult. I had an aquaintance that wanted radiant heat in his garage. It was a well insulated building and only needed 30,000 buth to heat it, so he fired it with a gas fired domestic water heater. In theory it would work. However, he did not want to heat it all of the time. So when he went to turn up the thermostat, the heater would fire for 24 to 30 hours constantly until the mass of the concrete was up to temp. I did some calcuations and this was correct given the mass of the concrete in the garage.

You need a piping arrangement and controls to insure that the slab will not get overheated. Otherwise expansion and cracking problems could occur.
steamup
 
Stoker Coal Boiler: Axeman-Anderson AA-130, Keystoker K-6
Hand Fed Coal Boiler: HS Tarm 502 Wood/Coal/Oil
Coal Size/Type: pea, buck, rice

Re: How low does your boiler temp drop when a zone is calling?

PostBy: lsayre On: Sun Feb 12, 2012 2:12 pm

I can see where a radiant slab would send a good load of cold water back to the boiler. My garage has finned tube baseboard heat, so although the garage zone sends a slug of cold water it does not cause nearly the problem that is being described here.
Last edited by lsayre on Mon Feb 13, 2012 10:45 am, edited 1 time in total.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Anthracite Pea
Other Heating: Resistance Boiler (if I ever get it fixed)

Re: How low does your boiler temp drop when a zone is calling?

PostBy: KLook On: Sun Feb 12, 2012 3:25 pm

I solved ALL my slab problems, (mine was improperly piped), by installing an Injection system. tecmar control. I constantly circulate the water in the slab and only add heat when it needs it. The outside sensor dictates the water temp that is allowed to go into it and I just play with the heat curve to fine tune it. I highly recommend this system, but he controls are pricey. Maybe find used ones on ebay?

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: How low does your boiler temp drop when a zone is calling?

PostBy: Short Bus On: Sun Feb 12, 2012 3:59 pm

One solution may be to use a heat anticipating thermastat, I have them in my house, they are simple, once you understand the reasoning. I probalby would not have bought them had I known, but I'm glad I have them. This is a relativly inexpensive solution that may be worth trying.
Heat anticipating thermistats turn on when the temperture is below the disired temperature, and they anticipate that the room is warming and shut off. The reason for this is once hot water starts flowing into a slab, radiators or baseboard the heat is in the room and the thermistat anticipates that the room will warm, and understands it may take some time for the heat to get out of the heating system and to the thermistat. I have a four cubic yard slab in my 16X16 main room and the thermistat clicks on maybe three times an hour or more when it's cold. This constant switching never lets the slab get completely cold.
When these thermistats call for heat a tiny heater turns on inside the thermistat, causing it to shut off premature, turning the tiny heater off, and now the thermistat experiances room temperature and turns back on. Mine turns on for as little as 10 minutes and I know the slab isn't making heat that fast, then it will be off for maybe twenty minutes, and on again, and so on, I have an outdoor thermometer in that room and when I set it to record the high and low for the day somtimes they are both 70 F.

Attached are some pictuers of my thermistat, I added a light to indicate on or off. When the thremistat switch is open the light comes on, and when it closes the light goes out, don't worry about that. In the last picture you will see the heat anticipater dial is set at almost maximum anticipation. This thermistat will stay on for hours if I come back form vacation and turn the temperature back to normal.
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Short Bus
 
Stoker Coal Boiler: Kewanee boiler with Anchor stoker
Coal Size/Type: Chestnut / Sub-bituminous C
Other Heating: Propane wall furnace back up only

Re: How low does your boiler temp drop when a zone is calling?

PostBy: Wood'nCoal On: Sun Feb 12, 2012 4:54 pm

I moved this discussion to the "Controls" heading since it pertains more to controls and plumbing then to a specific brand of boiler.
Wood'nCoal
 
Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert

Re: How low does your boiler temp drop when a zone is calling?

PostBy: chevymatt On: Sun Feb 12, 2012 9:14 pm

Thanks Kevin and shortbus for the info. I'll def check into both
chevymatt
 
Stoker Coal Boiler: AHS S260

Re: How low does your boiler temp drop when a zone is calling?

PostBy: KLook On: Sun Feb 12, 2012 10:54 pm

This might work?? Need the experts to judge the worthyness. ;)

http://www.ebay.com/itm/Tekmar-253-New-256-/150747864562?pt=LH_DefaultDomain_0&hash=item231945ddf2
This link is broken, either the page no longer exists or there is some other issue like a typo.


Kevin

I should point out that this control wants to regulate the boiler, it is made for oil or gas, I think mine does also but as it is coal I just dont use this feature. The coal has to "Idle" after all. Mine just regulates the injection pump for the slab. If no thermostat is installed, it defaults to 68*. I have had to decrease the heat curve to get temps lower then 68. I think my thermostat is defective below the default point. It will go higher. No matter, I am maintaining 64* easily with a very defective pipe install.
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: How low does your boiler temp drop when a zone is calling?

PostBy: KLook On: Sun Feb 12, 2012 11:20 pm

Here are 2 for $100! May need a sensor.


http://www.ebay.com/itm/Tekmar-356-and-153-/290670242287?pt=LH_DefaultDomain_0&hash=item43ad4be9ef
This link is broken, either the page no longer exists or there is some other issue like a typo.


Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: How low does your boiler temp drop when a zone is calling?

PostBy: KLook On: Sun Feb 12, 2012 11:29 pm


http://www.ebay.com/itm/Tekmar-071-Sensor-/150747875122?pt=LH_DefaultDomain_0&hash=item2319460732
This link is broken, either the page no longer exists or there is some other issue like a typo.

This goes with the 253, he is selling it separately, :x

Kevin
KLook
 
Stoker Coal Boiler: Harman VF 3000
Coal Size/Type: rice, bagged, Blaschak
Stove/Furnace Make: Harman (Back In Maine)
Stove/Furnace Model: VF 3000

Re: How low does your boiler temp drop when a zone is calling?

PostBy: McGiever On: Sun Feb 12, 2012 11:53 pm

365 is injection, varies pump speed...but reqs. specific piping arrangement...manuals available online.
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Hot Air Coal Stoker Stove: HARMAN MAGNUM
Hand Fed Coal Stove: RADIANT HOME AIR BLAST
Baseburners & Antiques: OUR GLENWOOD 111 BASEBURNER "1908"
Coal Size/Type: PEA / ANTHRACITE, NUT-STOVE / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: How low does your boiler temp drop when a zone is calling?

PostBy: Rob R. On: Mon Feb 13, 2012 8:14 am

The whiz-bang Tekmar controls would be an elegant solution, but a strap-on aquastat on the primary loop would be a very simple and inexpensive way to protect the boiler from excessively low temperatures for the rest of the winter. You could wire it to shut down the primary circulator, or just the garage circulator. Just an idea...
Rob R.
 
Stoker Coal Boiler: EFM DF520
Coal Size/Type: Rice/buck
Other Heating: Dad's 1953 EFM Highboy

Re: How low does your boiler temp drop when a zone is calling?

PostBy: LsFarm On: Mon Feb 13, 2012 4:41 pm

I have my supply/return to my shop slab as a primary loop, I have a mixing valve that can be turned down to 85" in the secondary loop, which is the floor system.. there is a Taco 007 pump running 24/7 circulating mixed water to the slab, so it stays at roughly 55* depending on how cold it is and how much heat the shop is losing to outdoors..
the primary loop runs constantly, and is therefore also at a steady delta-T.. so there is no shock of 40 gallons of 80* water hitting the boiler, when the slab wants heat.. the slab is sipping heat all the time..

This constant small load on the system also acts like a timer on the boiler,, about every 30 minutes the boiler runs and brings the water up to 160*..

Yes I do have a few pumps running 24/7, but they are .78amp, so about a 100 watt expense..
Probably better than your 'tankless' DHW heater trying to help out the AHS260,,

And YES that tankless is NOT plumbed right,, it should never be in series or in any way be able to 'help' bring up the boiler water temp, only bring up the water temp going to the taps in the sinks and showers/tubs/laundry.

Greg L
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland