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Nick W

Nick W

Joined on September 26, 2003

Last Post on February 6, 2014

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Return temperature of 130°F looks safe

@ February 6, 2014 1:02 PM in Flue gas due point question

It looks to me like a return temperature of 130°F is OK in an atmospheric cast iron boiler at 5600 ft with CO2 at 8% or less, assuming 850 Btu/cf gas won't raise the condensing temperature from the theoretical 123°F.

My concern is not space heating, as those zones cycle between 150°F and 170°F. But my indirect can drop the return temperature to 130°F for quite a while, as our water supply is now about 40°F and falling.

Thank you all for the comments.

Bob,

@ February 5, 2014 3:27 PM in Flue gas due point question

Here is an excerpt from a paper by Rosemarie Halchack, the gas quality engineer at Xcel:

"As noted, natural gas supplies on the Colorado Front Range are blended with air for the purpose of Btu stabilization. The original supply of natural gas to the Denver area contained high levels of nitrogen and was characterized by Wobbe factors of 1200-1250. As additional supplies with Wobbes of 1300-1350 became available from Wyoming, the issue of interchangeability became critical. In the late 1970s, the Institute of Gas Technology performed appliance testing and interchangeability calculations to determine that the new supplies could not be safely substituted for the existing base gas because of the risk of yellow tipping and incomplete combustion.

"The most feasible and economic solution to the interchangeability problem was to blend air into the new supplies to reduce the Wobbe to the required values. Air compressors have been installed at three stations supplying Denver and the surrounding areas. The quality of the gas-air mix is controlled using measurements of oxygen content and Wobbe Index. The air added is typically 5-8 percent of the gas flow, and the composition of the resulting mixture is thus significantly above the upper flammability limit.

"In other situations, Xcel Energy has solved interchangeability problems incurred by new gas supplies by reorificing entire distribution systems. The city of Fort Collins, located 70 miles north of Denver, was reorificed for higher heating value gas in 1968, and the remaining area north of Denver was reorificed in a "High Therm Project" in the early 1980s. In 1995 a reorificing effort in the mountain area near Vail was completed. Reorificing is a time-consuming and labor-intensive project that is undertaken only if no other alternatives are available. The company must enter all homes and businesses to install new orifices in the burners of all appliances and to adjust air shutters and manifold pressures to ensure proper combustion. Follow-up inspections are necessary to verify that the work has been properly performed and minimize the liability associated with improper adjustment."

Zman,

@ February 5, 2014 11:26 AM in Flue gas due point question

It is page 40 of the ASHRAE pdf you mention that got me curious about the condensing point of the flue gas in a natural gas boiler here in the Denver area. But the gas here has a Btu content of only about 850 Btu/cf as a result of the lower atmospheric pressure and the addition of air by Xcel. I suspect this may materially alter the condensing point (aka dew point). How can one set up outdoor reset for a cast iron boiler without knowing this?

Flue gas due point question

@ February 4, 2014 10:23 AM in Flue gas due point question

Can anyone tell me what the flue gas dew point is for a gas boiler at 5600 ft altitude burning the gas shown in the following spread sheet? Flue gas CO2 is 8%, RH 30%, ambient air temperature 65°F.

http://www1.xcelenergy.com/webebb/html/Gasqualityzone.asp

Uneven insulation may well be the culprit.

@ February 22, 2013 9:34 PM in Living Room Cold (Hot Water System)

Uneven, inadequate, or missing insulation is a frequent, if not the most common, cause of cold rooms.

Neighbors of mine lived with a very cold bedroom for 35 years. At my suggestion they had a handyman help them blow additional cellulose insulation into the attic. About half way through the project the handyman reported there was no insulation over the bedroom that had been so cold for so long. This bedroom was the farthest room from the attic access in the garage, and the lack of insulation there could not be seen from the access hatch. The problem has been solved.

These are the experts

@ April 17, 2012 9:06 AM in Ventilating a Cape attic

You might find answers here: www.buildingscience.com.

These are the experts

@ April 17, 2012 9:06 AM in Ventilating a Cape attic

You might find answers here: www.buildingscience.com.

Honeywell zone valve?

@ March 5, 2012 7:40 PM in New Amtrol Boiler Mate running out of hot water

Just about every indirect I have seen in my neighborhood has a highly restrictive Honeywell zone valve on it. My 41 gallon indirect is hooked to an 87,000 Btu boiler; we never run out of hot water. The calculated flow rate is 14 gpm; delta T is 10F.

Honeywell zone valve?

@ March 5, 2012 7:40 PM in New Amtrol Boiler Mate running out of hot water

Just about every indirect I have seen in my neighborhood has a highly restrictive Honeywell zone valve on it. My 41 gallon indirect is hooked to an 87,000 Btu boiler; we never run out of hot water. The calculated flow rate is 14 gpm; delta T is 10F.

Honeywell zone valve?

@ March 5, 2012 7:39 PM in New Amtrol Boiler Mate running out of hot water

Just about every indirect I have seen in my neighborhood has a highly restrictive Honeywell zone valve on it. My 41 gallon indirect is hooked to an 87,000 Btu boiler; we never run out of hot water. The calculated flow rate is 14 gpm; delta T is 10F.

Honeywell zone valve?

@ March 5, 2012 7:39 PM in New Amtrol Boiler Mate running out of hot water

Just about every indirect I have seen in my neighborhood has a highly restrictive Honeywell zone valve on it. My 41 gallon indirect is hooked to an 87,000 Btu boiler; we never run out of hot water. The calculated flow rate is 14 gpm; delta T is 10F.

Honeywell zone valve?

@ March 5, 2012 7:39 PM in New Amtrol Boiler Mate running out of hot water

Just about every indirect I have seen in my neighborhood has a highly restrictive Honeywell zone valve on it. My 41 gallon indirect is hooked to an 87,000 Btu boiler; we never run out of hot water. The calculated flow rate is 14 gpm; delta T is 10F.

Won't work on White-Rodgers 3-wire zone valves.

@ March 4, 2012 6:07 PM in Nest t-stat needs 24v

A neighbor called yesterday. She had just shelled out about eight Benjamins for three Nests. She was confused about a "black wire" and asked me what it was for. I told her the Nests won't work on her White-Rodgers zone valves and to take them back. I suggested she buy White-Rodgers1F80-0471s. She has older 1F97W-71s, but has trouble resetting them when she replaces the batteries.

John Siegenthaler says

@ May 4, 2011 12:46 PM in Water velocity

in Modern Hydronic Heating, "All down-flowing piping should be sized to maintain a flow velocity of at least 2 ft/sec to effectively entrain air bubbles." That's 3.25 gpm in 3/4" type M copper.

Size is important, too.

@ February 25, 2011 12:40 PM in Expansion tank replacement - 3 questions

Remember, if the tank is too small, the pressure may rise high enough to open the safety relief valve even if you have the correct pre-charge pressure in the tank. I'm sure someone here can tell you how to calculate the size you need.

Poor insulation or air leaks?

@ January 28, 2011 12:34 PM in whats the max run for fin tube base board?

In my very limited experience, most cold room problems are cause by inadequate insulation or air leaks rather than by heating system faults.

Heat lamps in the ceiling work well.

@ January 28, 2011 12:22 PM in heat for master bath

We have a weirdly shaped bathroom that is hard to heat. It has 4-1/2 feet of baseboard radiator, but the radiator is poorly located to heat the entire bathroom. The builder wisely installed two 250-watt heat lamps in the ceiling. These add about 20 Btus/sf and make the bathroom very comfortable for bathing. The heat lamps are operated manually with wall switches. They warm up the floor very quickly.

It probably is CO.

@ November 13, 2010 2:05 PM in Killer Coffee.....

I know CO is put in bagged salads to keep the lettuce from turning brown. It may be put in coffee containers to keep the coffee from going stale.

When I used the term "2/5"

@ May 2, 2010 1:21 PM in How do you connect a WR1361 to Taco ZVC406 for DHW

I meant terminal 2 or 5, as they both are the same terminal.

Terminals 2 & 5 are the same

@ April 30, 2010 10:59 AM in How do you connect a WR1361 to Taco ZVC406 for DHW

There are only 5 terminals on a 1361 valve head; there are 6 on a 1311. Both 2 & 5 are the common terminals; they are the same terminals. This setup allows you to connect more wires to the common. So if you count 2 & 5 as one, there are only 4 terminals on a 1361 valve head.

Terminal 6 is missing on the 1361, as the valve is self closing as long as it has power. The 1311 valve has a terminal 6, as it is used to close the valve.

Terminal 1 is the 25-volt power terminal. Power must be connected to terminals 1 & 2/5 or the valve will not open or close.

Terminal 4 is used to open the valve. A 2-wire aquastat or thermostat would connect to terminals 4 and 2/5.

Terminal 3 is the end switch.

A new weather station in Alta

@ April 29, 2010 1:57 PM in design temp in Alta, Utah?

reports 7 days below zero this past winter, with the low being -10° F.

TACO needs to improve their documentation.

@ April 29, 2010 1:33 PM in How do you connect a WR1361 to Taco ZVC406 for DHW

You are welcome, Ed.

Just try and figure out how to wire WR 1361 zone valves to a TACO ZVC when all the zone valves are 1361s and all the power for the valves comes from the ZVC terminals.
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