Forum / Strictly Steam / EDR / BTU's steam / hot water

## EDR / BTU's steam / hot water (4 Posts)

• ### EDR / BTU's steam / hot water

When I measure up an existing radiator and calculate the EDR, I know you multiply by 240 to get the BTU's for steam. But for hot water I believe you multiply the EDR by 150 for 170 degree hot water - I seem to remember reading this in one of Dan's books - can anyone clarify?
• ### That's right

assuming you're working with a max boiler temp of 180° F.
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• ### Correct, and

keep in mind that the reference temperature (the 170F) is the "average" water temperature. This is what Steamhead is saying, re: 180F supply water, but presumes a 20 degree drop.

If you size for condensing boilers using 140F maximum supply (Say 130F average assuming 120F return), you get about 90 BTUH per EDR.
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