State of MN/WI Small Boilers

1. State of MN/WISmall Boilers Dan Chudecke Mulcahy Co

2. Background • Mulcahy Company 21 Years • Best known for Hydronics • Have been in the boiler business for over a decade – • 100’s of boilers installations • I am an actual Boilermaker

3. Preview • Discuss modern condensing boilers • Design • Installation • Inspection • Maintenance • McDonnell and Miller LWCO • Recent Mishaps • Solutions

4. High Efficient Boilers • Greater portion of the overall market share • At last count 40+ manufacturers offer some form of condensing boiler • All are a different from each other • All are VERY different from “Old School” boilers they are taking the place of

5. Natural draft Separate components for each function Minimal moving parts 83 % Max – Nat. Draft 85% Max – Fan Assit High minimum return water limitations Fairly High Mass Forced draft venting Combination controls that are often proprietary More parts and switches 99% efficient possible Lower return water limitations Fairly low mass Comparison

6. Full modulation usually done with full speed blower and damper Burners act like ‘Flamethrower’ Simple controls Full Mod usually done with variable speed blower and ‘Zero Governor’ gas valve Burn is more contained at a mesh or ceramic surface Monitor multiple points Comparison

7. 100% 98% 1/3 Input 96% 1/2 Input 94% Full Input 92% Efficiency, % 90% 88% 86% 84% 82% 60 80 100 120 140 160 Return Water, F Typical Condensing Boiler Efficiencies-i.e. Laws of Physics Rule This is what is advertised!

8. LATENT HEAT 10.2% SENSIBLE HEAT 89.8% Latent – Definition: Latin for “hidden” Comes from the difference between the Higher Heating Valueand the Lower Heating Valueof the fuel. Heat that can be measured or felt by a change in temperature Comes from theLower Heating Value of the fuel. ENERGY CONTENT OF NATURAL GAS

9. Condensing boiler Total heating value Heating system Sensible heat Useable heat Condensation Latent heat MORE USABLE HEAT THROUGH CONDENSATION What influences the rate of condensation?

10. THEORETICAL PERFECT NATURAL GAS COMBUSTION OR STOICHIOMETRIC The CO2 = 11.9% The CO = 0 ppm Excess air 0% 1 part gas 9.7 parts air by volume Foil 11 Nov 2005

11. REAL WORLD NATURAL GAS COMBUSTION WITH GOOD BURNER TECHNOLOGY The CO2 = 9.5 to 10% The CO = 0 to 20 ppm Excess air 20 to 25% 1 part gas 9.7 parts air What can cause the amount of excess air to change after start-up? Foil 12 Nov 2005

12. Lambda Pro Technology

13. 120 110 Physical principal 100 90 Rich Combustion (Bad) Lean Combustion (Good) 80 70 Calibration Gross Flow [ % ] richer 60 50 76 Pct leaner 40 30 20 10 Io-Signal [%] 0 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 Excess Air = 1.3 Lambda [ - ] VITODENS 200 WB2B Lambda-Pro self calibration

14. gas valve premix air/gas air Air/Fuel Coupling PG= PA gas 1 to 1 ratio PG PA VFD

15. Heat Exchanger Materials • Wide range of condensing heat exchanger materials • However all use a vent material capable of handling the acidic flue gasses.

16. Wall Hung “Mod Con” • 50,000 & 400,000 btuh • Floor mounted or wall mount • Can be direct vented • +92% efficient

17. Typical Wall Hung Mod-Con Features • Lift off front panel • Easy component access • Floor or wall mount • Quiet - less than 45 db • Light weight - less than 100 lb. • Sentry 2100T Control • Spectacular turndown • 6:1 (150), 8:1 (200)

18. The Vitodens 200-W, WB2B boilers come equipped with Lambda Pro, the industry’s first intelligent combustion management system. The boiler adjusts automatically to any gas type and quality without the need for a fuel conversion kit. • The fuel flow is checked against the optimum flame signal and the correct lambda setting is determined for the current burner cycle.

19. Composite Controls

20. GX Features • Stainless steel jacket • SS screws, nuts, studs • SS heat exchanger • Metal fiber burner • Fully modulating

21. Giannoni Heat Exchanger

22. Giannoni Heat Exchanger 316L Stainless Steel

23. The Giannoni 316L stainless steel oval section measures approximately 25 x 7mm with a wall thickness of 0.7mm Equal ???? Viessmann corrosion resistant high grade 316Ti stainless steel. 1.5 mm wall thickness. Not even close!!

24. Giannoni Heat Exchanger primary combustion chamber condenser

25. GX Combustion condensate

27. Typical Mod Con Venting Option • Direct vent only? • Solid core PVC, ABS, Poly Pro, CPVC or AL 29-4C piping • for 180° return use CPVC • Provision for condensate removal

28. Typical Mod Con Venting • Direct vent only, • No inside air • Certified for direct vent • Potential freeze up • 12” above snow line • 4” lateral separation • 18”to 36” vertical separation • FOLLOW GUIDELINES

29. Inspect Burner

30. Clean Heat Exchanger Annually for Propane At least bi-annually for Natural Gas

32. Other Mod Con Boilers • Aluminum Heat Exchanger • Requires special glycol • Inhibitors in typical HVAC glycols respond badly to Aluminum • Systems should be tagged properly

33. Larger Input Boilers • Varying Heat Exchanger Materials • Stainless Steel • Cast Iron • Coated Copper • Ceramic • Aluminum • ALL drain off the condensate as it is formed

34. CONDENSING BOILER CONSTRUCTION HS Condensing boiler Hot Flue gas HR HR Flue gas HS Normal heating boiler HR • Condensing boiler requirements: • Counter-flow principle for flue gas and boiler water – optimal heat transfer • Parallel flow direction for flue gas and condensate – uniform flow with self-cleaning effect of heat transfer surfaces Foil 35 Nov 2005

35. Counter Flow Arrangement

36. Other Condensing Designs? • Primary Heat-X • Second Condensing Heat Exchanger • “2nd Swipe” type systems often get a few more points of efficiency

37. Compact Designs • Thru 6,000,000 input per device • Generally fit thru a standard doorway.

38. gas valve premix air/gas air Air/Fuel Coupling PG= PA gas 1 to 1 ratio PG PA VFD

39. Start-up and Installation • Each boiler manufacturer is different • Many require certified start-up for warranty to be valid • Here is a partial list of things to consider

40. Installation/System Design • Minimum Water temperature • Minimum Flow consideration • Glycol? • Condensate Treatment • Boiler condensate is a low grade acid that can ruin cast iron pipes • Running the liquid through limestone brings the pH to 7 • Sealed Combustion • Boiler Designers don’t really know what -20F is like • Outside Air temp can easily get below a conditioned spaces dew point

42. Dilute sulfuric acid reacts with metals via a single displacement reaction as with other typical acids, producing hydrogen gas and salts (the metal sulfate). It attacks reactive metals (metals at positions above copper in the reactivity series) such as iron, aluminum, zinc, manganese, magnesium and nickel. Condensate Neutralizers prevents acidic condensate from corroding drains and sewer systems, Neutralized condensate is more environmentally friendly

43. Testing • Blocked flue and blocked combustion air • Gas pressure loss going into the boiler • Gas shut off going to the burner • Loss of VFD/Fan • Test Manual reset boiler high limit • LWCO • Combustion setup at various input rates

44. Combustion • Setup should be per manufacturers recommendations • O2 readings are generally MUCH lower than what older boilers are setup for • For example – We set our boilers up for 3-5% O2 at high fire and 5-6% at low • Old guidelines were 4-10% - • 8-9% will likely cause C.O. problems

45. Maintenance • After the boiler has been in service for a period of time, the boiler should be rechecked (anything changed) • An annual checkup (if not more) is usually recommended/required for warranty reasons. • Some boilers require periodic parts replacement • Annual testing of the glycol is recommended and often provided by the glycol supplier

46. Boiler Questions?

47. McDonnell and Miller LWCO • Brief history of ….. Issues.

48. McDonnell & Miller • Mercury Phase Out • Overload Issues • Current 150/157 carries the same load capability-7.4 Amps @ 120V • The old switch was actually capable of more • Float Sticking • Changed bellows manufacturing process in June of 1999 (Last known modification) • “MD” Application

49. Questions