Boiler Over Firing?

Posted by rep on February 18, 2006 at 00:01:47:

I have an old Kewanee Type R Model 1736 that is rated at 700 SF/EDR and was told this unit will run at 80% efficiency. I realize it’s oversized but as it is seldom used I have no plans to replace it. I would like to increase the efficiency if I can. I suspect the burner is over firing.

Would the following calculation represent the amount the burner could be over firing?

700 SF/EDR Gross Output x 240 BTUH per SF/EDR (steam) = 168,000 BTUH Rated Gross Output at 80% efficiency.

168,000 BTUH divided by .8 = 210,000 BTUH Rated Input (estimated)

Current Firing Rate of 270,000 BTUH (clocked the gas meter) – 210,000 BTUH Rated Input = 60,000 BTUH amount of over firing per boiler rating?

The load on the boiler is about 68,330 BTUH for the radiators and 57,000 BTUH for the piping.

I need to understand what’s involved so I can recommend and monitor what the technician does.

1. To down-fire by 60,000 BTUH would I change orifice size or something else?

2. Would the manifold gas pressure need to be adjusted?

3. If I did down fire it by 20-25% would it run 20-25% longer to heat the radiators?

Thanks

Follow Ups:

• Re: Boiler Over Firing? HeatPro 10:37:41 2/18/2006 (2)
  • Re: Boiler Over Firing? rep 14:45:08 2/18/2006 (1)
    • Re: Boiler Over Firing? HeatPro 15:30:57 2/18/2006 (0)

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