Heating Help

@ March 5, 2008 1:57 PM in BTU or flow metering

There are a number of companies that market btu meters. One is Onicon; uses a turbine meter and temperature sensors with a small readout unit. There also exist companies that do this as a service, including the billing.

@ February 20, 2008 9:16 AM in 110 Degree Indoor Temp

I'll relate a couple of experiences and see what you all think...1. was called to a local laundry because they had a boiler problem. Found both lwco's jumped out and the high pressure switch with a jumper also-they had beenrunning it manually until the man reset hp switch tripped. They didn't want it fixed;too expensive just get it running. I placed a gas co. cylinder lock on the meter and told them they would have to call the utility to get it unlocked. Lost a customer, but slept that night. 2. A friend of the boss had an oil furnace in the basement with a stack switch that had malfunctioned and it was late Friday afternoon. I worked with it and adjusted and cleaned, but still didn't trust it. Boss talked me into letting it go over the weekend and converting to a cad cell Monday. Sunday night it failed to ignite and the stack switch hung up. After some time the firebox did ignite and blew out the side of the enclosure and set the house on fire. The fire department saved the house, but for me that was the last time-no more mr. nice guy. I don't care what the lawyers say, I will not leave an installation in an unsafe condition. It still amazes me the number of jumped out safeties that I find, even on industrial boilers and equipment.

@ February 19, 2008 8:29 AM in Bizarre problem. Solution found. Common behavior?

Yes, this is a common problem. The internal anti-scald valve seats are located upstream from the shutoff, so a small amount of leakage can occur if there is a pressure differential between cold and hot, such as a hot water recirculation pump.A pressure differential is also present when the indirect tank heats up, thus expanding that volume of water. This happened in the dorms built for the olympics in Atlanta, the whole building has warm domestic cold water. Fix is to add check valves in hot and cold lines going to the valve.

@ February 17, 2008 12:19 PM in devil's advo - radiant vs scorched

I just have to say this! Just came in from my shop with radiant floor. Floor temperature is 70 degrees, air temperature is 58 degrees, and I was quite comfortable with a short sleeve shirt on. Air temperature would have to be 70+ for the same comfort level. Nuff said...

@ February 4, 2008 12:12 PM in Cold Start-up

My reference material(ASHRAE) shows the specific heat of concrete with sand/gravel aggregate to be 0.22-0.25 based on moisture. At 150#/cubic foot the total weight would be 130,000lbs x .25 = 32400; so approx 35,000 btu/ degree rise with no loss. Hope this helps...

@ January 11, 2008 12:21 PM in SOLONOID VALVE ON STEAM

The minimum psi listed for the solenoid valves is minimum operating pressure differential, or in simpler terms the differential pressure required to overcome the internal spring on valve. Steam pressure would have to be over 5 psi on the inlet side and the outlet side would have to be at 0 psi. Depending on the type of steam system, this pressure may not be available..

@ January 8, 2008 9:22 AM in Anyone seen this?

Cobb EMC, north of Atlanta had an FM radio load shedding system starting in the mid 70s. Useage was voluntary and savings were promised. The utility promised to never shed more than one 15 minute interval per hour, but got greedy in the early 80s-I remember one period of 3 and 4 "hits" per hour. Times have changed and the current rate structure is set up for real time pricing for wholesale power, so the system was abandoned. Peachtree City, south of Atlanta had an experimental time of day metering system for some time, but it was never expanded. I believe the time of day metering system has the most chance of success, because the user must decide whether to use high priced or lower priced power.

@ December 20, 2007 8:39 AM in Free watt

Looks like a good system-produces 1200 watts of electrical power as well as providing heat from the exhaust. In simplistic terms, produces heating at 92% efficiency and matches output to heating loss, so it competes in efficiency with a mod-con. Looks like it would be cost effective only if electricity is above 15 cents/kwh-the higher the electrical cost the more cost effective. I have seen the package in person, but have not applied one yet. Honda certainly has the engineering expertise and quality control to produce a good piece of equipment.

@ December 19, 2007 10:06 AM in Conversion of vacuum condensate system

Quite frequenty, vacuum systems are installed up front because there is no way some of the loads can drain by gravity. Remember that there is no steam pressure in any of the emitters until the temperature of the piping and radiators rises above steam temperature. Is gravity drainage possible?

@ November 28, 2007 8:23 AM in Effects of glycol on BTU transfer

This is a misnomer-What is really being said is that the btu capacity is reduced at the same conditions. A reduction in heat transfer capacity will result in higher flue gas temperature and a loss in overall efficiecy due to the increase in btu's going out the stack. Combustion efficiency is not affected. The required velocity through the heat exchanger would not change because the same amount of heat is liberated by the burner, only more of it passes through out the stack.

@ November 27, 2007 8:50 AM in Hot Water Coils

try US Coil and air, I think there is a ratings calculator on their web site...

Expansion tank pressure

@ October 10, 2007 7:46 PM in Expansion Tank Pre Charge Pressure

The precharge pressure should be a small amount below the system fill pressure. Some diaphragm tanks will damage the bladder if the bladder is forced against the inlet for long periods. Ideal is for the bladder to be approximately 90% extended in normal operation. If the charge presure is higher than system pressure, then the bladder will be fully inflated and the tank will take on no water until the system pressure rises above the pre-charge pressure. Going in the other direction, if the precharge pressure is lower than the system fill pressure some of the acceptance volume is wasted; could have used a smaller tank.

Fuel mileage

@ August 8, 2007 5:15 PM in Looking for Prius reviews (GrandPAH)

Slightly off topic; but we own 2 Volvo V-70's, one 2002 and one 2004. Fuel mileage on the 2002 is 29+ (Turbo) and the 2004 is 31+. In addition the 2002 is filled with tools and test equipment-4000 lbs. The sad part is that the diesel counterpart gets 45mpg with the same power. Thanks to the Bush administration it is not imported. TDI technology is both more fuel efficient and cheaper than a hybrid, with no downside. The batteries on any hybrid do need replacement at some time, and the price tag is such that most get traded rather than get a new battery pack. I am not saying anything bad about hybrids, only that there are other options that are at least as fuel efficient...My 2 cents worth.

Desuperheaters

@ July 16, 2007 12:07 AM in R410a Discharge Temperature

Typical can compressors operate with 50-100 degrees of superheat with 410-a. The reason there are so many desuperheater dissapointments is in the design of the system. As we all know, you can't transfer btu's unless there is a temperature difference, so trying to add heat to a tank full of 140 degree water doesn't work. The solution is to preheat cold water and use it as make-up for the water heater. My geothermal system is set up in this manner using a standard 40 gallon water heater as a preheat tank. A circulating pump pumps a loop to this tank and the tank outlet feeds the service water heater. The preheat tank ranges from 95 degrees to 125 degrees, depending on the heat pump operating hours; inlet temperature is 60 degrees. I have seen many systems plumbed up with no circulator so there is only heat transfer when the unit is operating and there is a draw of hot water! Go figure...