Gas-Meter Clock Target Time

The inverse of meter clocking: the seconds-per-revolution a known test dial SHOULD take if the appliance is firing on rate, so you know the stopwatch reading to expect - sec = 3600 x dial x heating value / target rate. A 100,000 BTU/hr furnace on a 1 cf dial at 1030 BTU/cf should clock 37.1 s (on-rate window 35.3-39.0 s at +/-5%); a faster revolution is overfired, a slower one underfired. Clock with every other gas appliance off. The utility heating value and rating plate govern.

seconds-per-rev = 3600 x dial size x heating value / target rate; on-rate window = sec/1.05 (fast) to sec/0.95 (slow); target cfh = target rate / heating value.

First-principles meter-clocking arithmetic solved for the on-rate time, the inverse of the meter-clock tile (public); the heating value is an editable field.

The clocking arithmetic is public; the gas utility's actual heating value governs the result.

Estimate. AHJ and licensed professional govern.

Field names used by the API: target_input_btuh, dial_size_cf, heating_value_btu_cf, sec_per_rev, cfh_target

• On-rate time sec = 3600 x dial size x heating value / target rate (the inverse of the clock)field practice
• Heating value default 1030 BTU/cf natural gas (about 2500 for LP), editable; the gas utility's actual value governs and varies by supplyfield practice
• On-rate window +/-5% of the target: a faster revolution is overfired, a slower one underfiredfield practice