Presentation on theme: "For Steam Boilers & Hot Air, Fresh Air, et al.. Thermostat Demand Analysis over time resets burner fire time for steam boiler. This will remove the leads."— Presentation transcript:
For Steam Boilers & Hot Air, Fresh Air, et al.
Thermostat Demand Analysis over time resets burner fire time for steam boiler. This will remove the leads and lags associated with the over and under steam value. Interior space thermostat analysis anticipates needed heat replacement precisely.
Thermostat Analysis over time
Thermostat analysis was 68 % of the hour. The Ideal Demand Analysis we desire is 60% Thermostat call Subtract the =.8 (Time Change Factor) x 3 (minute Increment factor) = +2.4 Minutes If the old fire cycle time was 30 minutes, we add 2.4= 32.4 minutes. Demonstrate negative time change.
Limits of maximum and minimum burner fire times. Time limit avoid boiler fire short cycle and allow for radiator catch up.. All firings are thermostat initiated, and system pressure control limited. Initial start up fire times are determined by how long it takes to meet system pressure controls from a cold start.
Controller demand analysis (previously discussed) resets fire times, from hour to hour. Burner fire time will be increased or decreased at the end of each analysis period ( 60 min.) in order to meet the ideal thermostat demand ratio. (60%). On mild days this may well allow comfort satisfaction at lower than system pressure limit at the boiler. Radiators may well heat ½ way across. Fire time adjustments
Start-up fire time = the time it takes to satisfy pressure limit from a cold start. (15-90 minutes) Boiler pressure controls and thermostat satisfaction can over ride the fire time.
Test pressure gauges and pressure control. Boiler should be making steam within minutes. If not the boiler may be undersized. Check that boiler burner rate is high enough to produce good steam. (see boiler instructions) Analyze burner for proper firing and minimum excess air. ( CO2 %, stack temperature.) Check chimney flue, piping insulation, vents, traps, condensate return lines and boiler water level.
The amount of time it takes to recover to steam delivery after a break minutes Minimum = Fire Time 10 min.
Each building has its own rhythm. Factory settings can be adjusted if needed by the installer.
The goal is to have the thermostat satisfied into the break. There are savings and comfort advantages as the thermostat is satisfied after the burner is off. The thermostat overrides all calls for burner firing. All control points operate in series.
If the thermostat does not call heat for more than one hour the controller sets back to Start up time, at thermostat activation. Boiler can be shut down by pressure, thermostat, or controller analysis time.
Maximum Burner Time minutes Fixed break time minutes. Start up burn time: 20, 30, 45, 60, 90 min. Min Burn time : 10 minutes.(short cycle prev.) Ideal demand ratio.5,. 6,.7,.8 Analysis time: 40, 60, 90 minutes
Thermostat activity analysis within the hour will determine the increase or decrease adjustment of the burner fire time in the following hour. Actual demand ratio vs. Ideal demand ratio determines + or - to length of fire on time, adjustment from previous hour calculated fire time.
Actual demand ratio = 70 Ideal Demand ratio =.60 ( )=.10 x 10= 1 time change factor Time increment factor= 2 minutes Previous hr. fire time 30 minutes 1 time chg.. factor x 2 min = +2 min Prev. fire time 30min + 2 min= 32 min New Burner fire time 32 min (increase)
Annual service is required for all boilers and furnaces. Flame check Excess air, Carbon Monoxide, Good distribution, safety controls, Ware from corrosion, chimney condition, fuel supply, filters for fuel and air, Exhaust gases, water quality, air in piping, venting of air, water pressure, Safety checks efficiency and comfort.
Carbon Monoxide Poisoning Gas boilers and oil fired boilers and furnaces ??? Its the law !! Why?
Blood Chemistry Odorless, colorless, Source: improper chimney vent of exhaust. Harm: CO attaches to red blood cells and are not recognized by our respiratory system. We cannot use them in the cells. They never leave the red cell and we starve from lack of oxygen. Cure: Hospitalization immediately. Prevention: Annual heating system service. Carbon monoxide detectors. Replace every five years.
Boiler water level. 1/3-1/2 water in fill glass Pressure monitoring lbs Blow down auto refill devices to remove rust Watch it cycle for a full two firings to verify pressuretrol safety operation. Check for short cycling. Check for continuous boiler firing. (longer than 40 minutes) This means you need to talk to your boiler service to explain. Check that all radiation is getting steam.
Steam is delivered as soon as it is generated. Traveling at great speed it will satisfy BTU demand quickly. It is most important that all system components are in good working order as designed. It can not be overemphasized, that complete inspection service and repair maintenance be done, annually by a professional.
Steam radiators heat and cool quickly. A steady radiation of BTU is the ideal. How do we do this evenly. By controlling the pressure to the need of the room. WE control the pressure by cycling the boiler to put BTUs in for BTUs needed. Some times the radiator may be hot but only half way across.
Boiler firing rate and oil nozzle size must be proper for the boiler to have efficient heat exchange from the fire to the waterside. If the nozzle is too small the boiler will take forever to heat. Steam pressure should be met in less than 30 minutes. If not have the boiler fire size checked by a professional boiler person. See manufacturers suggested gallons / hour. This information can be found at manufacturers website.
Many systems have had the asbestos insulation removed. Few replace the insulation due to the added expense. With fuel prices going up, insulation return on investment is becoming very attractive. The system was designed to work with insulated pipes. Most steam systems can be reinsulated for 5-10 dollars per pipe foot. You are wasting the heat in the pipes if you do not.
Proper boiler piping measurement check. Testing cleaning and repair of: air vents, traps, safety controls, chimney inspection, flue gas analysis, heat exchange cleaning, make up water supply rate, piping insulation, condensate return systems and boiler water, fuel supply and storage. Proper venting of boiler room for fresh air and fire prevention. Carbon Monoxide detectors are required.
Out door temperature changes take hours before being reflected in interior heat loss. Boiler is on before it is needed. This causes uneven over heating, and open windows. Indoor thermostat sensor takes all heat loss into consideration from the occupied space, where the people are. No wasted heat.
Steam heat now has the opportunity to be comfortable and efficient with the intelligent management offered by Exquisite Heat control John Cockerill US Patent: 6,402,043