Short run time for Circulators

Re: Short run time for Circulators

PostBy: stoker-man On: Wed Nov 19, 2008 4:11 pm

If the solo return line is on the same side as the aquastat, the cold water is hitting the probe and shutting off the circulator, while the other side of the boiler remains hot. If the solo return line is piped to the other side of the boiler, the aquastat doesn't sense the drop in water temperature, so the burner doesn't come on. That's why two return lines are needed.
stoker-man
 
Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove

Re: Short run time for Circulators

PostBy: IceDog On: Wed Nov 19, 2008 5:50 pm

Thanks for the replies and I hope I can explain what I have:

I do have a Triple Aquastat-Relay modem L8124AC. THe problem I see is I have the AC hot connected to L1 and the neutral connected to L2. B1 is the hot feed to the stoker motor, and B2 is the neutral to the stoker motor. There is also a RED hot feed wire connected to ZR, witch comes from the stoker timer. I have measured all of this and it works fine - BUT - there is no wires connected to any of the following terminals. C1, C2, ZC, or either or the two T terminals. Therefore the only time B1 and B2 get power to the stoker is when either the timer kicks on from the red wire, or if the low limit is met. It does not kick on when the circulators start, nor does it stop the circulators when it reaches the low limit. I know it's a wiring issue, and if anyone could help me with how to properly connect it I would appreciate it.

The circulators (I have two circulators) are mounted on the old oil burner which I have shut down now and they are controled by a Honeywell R845A relay. That relay basically has the two thermostat wires and the AC line voltage. When the thermostat kicks on the relay engages and the circulator runs. I can only assume the oil burner must have not "kicked in" when there was a call for heat, and since the oil burner "heats" quicker than the coal burner I guess I never noticed an issue.

I do have the aquastat set for 160 - 200 with a 15 degree differential. Should I set the differential to 10 degrees?

As for the bypass loop I guess I may have learned something here. There is a pipe that comes off of the top (feed) of the boiler and runs down to where the return goes into the boiler. There are no valves. This was the same set up that is on my old oil burner. I assumed that some of the boiler hot water went down and mixed with the return water and back into the boiler, BUT from Stoker-mans explanation I think that some of the return water should "bypass" going into the boiler and back into the radiator loop, there-by mixing the return with the feed and not allowing the full output of the boiler to exit. Since I do not have any valves wouldn't this promote the maximum amount of bypass???, or is the bypass installed incorrectly. Where should these valves be installed. I assume just before the input of the return on the boiler to force some of the water back up the bypass pipe?

I was turning my thermostat down 8 to 10 degrees during the day, but I will make sure I don't more than 5 degrees anymore.

One other question is my coal/air feed. It is set at 4 coal and 4 1/2 air. Since I now an using my heat on a regular basis should I increase the coal feed to get more BTU's out of the boiler and a faster recovery time?

Thanks,

IceDog
IceDog
 
Stove/Furnace Make: EFM 520
Stove/Furnace Model: Yellow Flame (Hot Water Oil)

Re: Short run time for Circulators

PostBy: cArNaGe On: Wed Nov 19, 2008 7:38 pm

http://efmheating.com/manuals/DF520%20Manual.pdf

Page 15 shows you how to wire your boiler.

The zr from your timer should be neutral.
What kind of timer do you have? Is it working with the hot hooked up?
Is your 8145a relay tied into your oil boiler?
Are both circulators on the R845a relay?
Do you have two thermostats going to your relay?

From what I'm reading, you have two circulators (two zones) and two thermostats running off your relay. The L8143A thermostat lets you run one circulator off of it. You need that zone's thermostat to go to the TT on the L8124A. Your second zone would run off the R845a relay. That zones thermostat goes to the relays TT.
The R845a has to tell the stoker to start. Thats where the wire from the relay goes to the zc and zr.

Double check your wiring. I'm almost possitive your ZR should be neutral.
cArNaGe
 

Re: Short run time for Circulators

PostBy: stoker-man On: Wed Nov 19, 2008 7:47 pm

ZR runs to the #4 terminal of the timer. That's what the timer energizes every half hour/hour.

If you aren't using C1, C2 (circulator) or TT, it means you don't control it with a thermostat or use a circulator.
stoker-man
 
Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove

Re: Short run time for Circulators

PostBy: IceDog On: Thu Nov 20, 2008 4:30 pm

Both of you have been a great asset in helping me learn how the aqua stat and relays work. With your advice, looking at other set ups, the wiring diagram in the EFM manual (why didn’t I think to look there!!!), and measuring the voltage on the terminals when the relays kick on/off, I was able to get a pretty good handle on this.

I have the coal boiler and oil boiler set up as individual units (separated by ball valves). This allows me to completely shut down one of the units and run the other. They share circulators, thermostats, and the piping distribution system. Each unit has its own L8124A Triple Aqua stat relay on it. I assume that is why the plumber ran each thermostat (one for the first floor, and one for the 2nd floor) to the two R845A relays (basically this was the easiest way for him to do it!). If he would have wired the thermostat to the aqua stat and used the C1 C2 terminals to feed the circulator it would not have worked when I shut that unit down and turned on the other unit. The problem is the R845A's are just relays and turn the circulator on when the T-stat calls for heat and will run until it’s satisfied. They don’t give me the benefit of the L8124A Triple Aqua stat relay, by starting the stoker when the T-stat calls for heat, or by shutting down the circulator when the low limit is reached. I have a tank-less hot water coil in each unit. You can imagine when the low limit is reached on the coal burner, and the circulator keeps running the water through the system, that it takes a great amount of time to bring the boiler back to temperature and it’s difficult to maintain a decent domestic hot water supply. I think by having the stoker start as soon as the T-stat calls for heat, and shut down on the low limit, I should be in pretty good shape.

I’m thinking if I run the thermostat wires to a double pole double throw switch (on-off-on), it would allow me to choose which aqua stat is being controlled by the thermostat. Since I already have to close and open valves, as well as main power when I change from one unit to the other, it would not be a big deal to also throw the switch to control the thermostat.
The question I have now is how to connect the C1 and C2 from each aqua stat to the circulator. If I just use a junction box and connected both C1’s to the hot wire of the circulator, and both C2’s to the neutral of the circulator it would allow power from the aqua stat that is currently being used to power the circulator. [u]The only issue is that the junction would also put power onto the C1 C2 terminals of the aqua stat that is not being used. Since I wouldn’t have any AC power going to the input of that aqua stat, would it be a problem to basically be “back feeding” the AC onto those terminals? [/u] If so, I guess I could get a single pole, double throw switch to isolate the voltage and only send the AC from the aqua stat being used to the circulator, and isolating the other aqua stat from that voltage.

I want to keep the number of switches and ball valves that must be “thrown” to a minimum. I know I will be able to understand it, but if I die my wife will never figure it out!!!

I guess the real question here is if it’s a problem to have AC on the C1 C2 terminals of the unused (and unpowered) aqua stat?

Thanks for any input.
Ice Dog
IceDog
 
Stove/Furnace Make: EFM 520
Stove/Furnace Model: Yellow Flame (Hot Water Oil)

Re: Short run time for Circulators

PostBy: stoker-man On: Thu Nov 20, 2008 5:21 pm

A word of caution about using a DPDT switch to use two tstats on the TT terminals of the aquastat........and it might not even apply, but any arcing when switching the blades possibly could burn out the heat anticipator of the tstat. I might be wrong, but investigate that idea further.
stoker-man
 
Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove

Re: Short run time for Circulators

PostBy: Freddy On: Thu Nov 20, 2008 7:26 pm

CaRnaGe said a lot in his last paragraph. If you can digest & understand it, you'll be well on your way. The relay he mentions is the cure for most of your issues. A SR100 relay is a wonderful thing.

Here's how to get the wife to understand: (of course the switches and valves are labeled & numbered)
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Freddy
 
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined