EDR of this radiator

luketheplumber

I have a small 6 tube radiator that 1 foot tall. Would 1 of yall have the specs for this radiator?

luketheplumber

Steamhead

That's an unusual one. The short legs tell me it's probably a "small-tube" type. Check the section spacing- the distance between the center of one section to the center of the next one.

I've only been able to find 14-inch-tall rads so far. If the section spacing is 1-1/2" or 1-3/4", it's small-tube, about 24 square feet.

But if it's 2-1/2", figure on 32 square feet. This would be a large-tube rad.

Is this on a Vapor system?

luketheplumber

@Steamhead I don't believe so. I think this radiator was added later on as it's the only one like this on the system. The rest are normal tube radiators with a few column rads sprinkled in.

Would it be safe to guess on this one and throw in another 5-10k btuson the boiler to compensate for this radiator?

In that case, I'd need a 160k btu output boiler.

Steamhead

32 square feet is 7,680 BTU per hour on steam. What exactly are we doing here? New boiler? Steam or hot-water?

mattmia2

none of this is an exact science, you just need to be close, probably erring on the side of a little smaller, especially if you are using the IBR ft^2 of steam ratings with 30% pickup factor baked in

luketheplumber

@Steamhead working on replacing the boiler. I actually miscalculated and if I'm correct the system should do good with a boiler with an output of about 210k BTUs. So a boiler with an input of 252k BTUs should do the trick.

luketheplumber

My calculations. Please correct me if I'm wrong

Radiator 1, 30 sqf

Radiator 2, 18 sqf

Radiator 3, 87.5 sqf

Radiator 4, 32 sqf

Radiator 5, 87.5 sqf

Radiator 6, 84 sqf

Radiator 7, 84 sqf

Radiator 8, 52.5 sqf

Radiator 9, 18.75 sqf

Radiator 10, 18 sqf

Radiator 11, 50 sqf

Radiator 12, 50 sqf

Radiator 13, 40 sqf

Total EDR with a 1.33 pickup = 867.4925

Total btu output of the system = 208,198.2

Boiler that should fit the system best would be about 250k BTUs.

ethicalpaul

don’t do all that pickup and btu math, just compare your EDR to the sq ft of steam of the boiler

Steamhead

https://forum.heatinghelp.com/discussion/comment/1812036#Comment_1812036

This. The Square Feet rating already has the pickup factor built in. Note that if the new boiler has a CycleGard low-water cutoff, which stops the burner for a level check every 20 minutes or so, you lose a percentage of output capability. I wouldn't try undersizing a boiler for this reason.