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Since I am home bound for a while I wanted to examine dump zone ideas for my coal stoker boiler.
I have used Dans tried and true pump module with an Internal Air Separator , Airtrol Valve and a steel compression tank and I have one open tapping on the end of the boiler steam chest that is 3/4" NPT and it has a 6 inch pipe nipple and pipe cap in it now.
I have asimple system with 225 foot of 3/4 fin tube baseboard and a honeywell mechanical triple aquastat set with 150 low 170 high and a 10 degree diferential and a honeywell dump zone aquastat in the steam chest that turns the circulator on when the 200 degree high limit is reached with a ten degree differential and as it happens quite often in the warmer parts of the heating season the house over heats a lot and at times their is no heat call and the stoker stops running and the fire goes out after 5 minutes as the stoker is a flat bed stoker that does not hold the fire unless the hold fire timer turns on to keep the fire going. I have a B+G McDonnell & Miller RB122-E low water cut off as the first wired boile rcontrol.
And with a long spell of warm weather the fire goes out and that is another issue.
My thinking is either I use a large salvaged and tested hot water radiator steel piping and very small circulator or a Zurn garage heater hung up in the ceiling or with wall mount hanger.
The boiler vessel is 34 gallons in volume and the heating loop volume is very small being 225 foot of 3/4" copper fin tube baseboard and 20 gallons+-with the 10 gallons in the steel compression tank.
I do not want to use PEX tubing and I have ready access to steel pipe and unions. I just have to decide on whether I can get by with 3/4 black iron pipe, unions and ball valves to make the run to the heater or radiator.
The garage smallest garage heaters are 500+- with tax plus the cost of pipe and a circulator $100.00+- and a change in wiring adding a second run of BX from the new circulator to the single dump zone aquastat and wiring for the garage heater.
I am unsure if I can use the same single 12/3 BX leg for the dump zone circulator and the fan in the garage heater.
I want to keep it as simple as possible and I am thinking the second smaller circulator coming off the 3/4 tapping on the end of the boiler, feeding the radiator and then coming off the radiator returnto the boiler sump may be the best way to do this as the water will be very hot and the radiator will be large enough to shed the heat fairly quickly and return the cooler water to the boiler sump tapping that does not have the drain valve in it.
I would use isolation valves to valve off the circulator in any case to avoid water loss and a mess on the floor.
Thoughts and suggestions are welcome.