19 Feb 11 17:56
What would cause a a pulsating effect in a boiler would it be a faulty atomizer or oil temperature being to low? What does the excess air curve chart look at exit gas temperature or the air to fuel ratio? What type of heat transfer is taking place in a surface condenser radiant conduction or convection?
1. Pulsation in the combustion chamber can be do to poor air distributions, improper atomization, fluctuations in fuel content, control mis-operation, etc.
2. if the oil temperature is too low you won't be able to make full load, and atomization will be almost non-existant
3. Depending on the size of the boiler and its class, the controls will monitor air flows, fuel flows, steam flows, feedwater flows, , gas temperature, stack O2, sometimes CO. Air/Fuel ratio is commonly controlled with O2 trim, lead-lag control of the firing rate, and tied into the feed water controls.
Suggest you determine if you have a control cycling issue, or if it is a burner instability.
Put the fuel flow in manual and see if the pulsation goes away.
Most power boilers have both convection and radiant sections, with several forms of preheat.
You need to be more specific about the boiler(capacity), steam pressure, etc. They are complex systems, so you have to work your way through the checks carefully, and hopefully with some good techs.
Some of the smaller boilers may have none of the fancy controls, but they are not usually classified as power boilers.