Joined on November 26, 2011
Last Post on March 9, 2014
@ March 6, 2014 12:01 PM in Fuel use question?I make sure to collect them from the closest (or most similar) PWS. I go to www.degree-days.net, download daily data for the previous two (or more) months, then prune the data so it matches the meter reading or tank filling dates and sum those up.
Two things you need to consider: One is base temp -- for newer, better insulated houses, 65ºF is not a good assumption. The other is non-heating appliance use. Add up the gas or oil use over 3-4 non-heating months and divide that by the number of days to get an average daily use number and subtract that (multiplied by the days in the billing period) from the usage during the heating season.
@ March 6, 2014 11:32 AM in Newbie Hydronic questionsYour system will be simpler if you can design for a single water temperature instead of two. Size the RFH first and then pick radiators using that supply temp.
Radiators (either panel type or cast iron) work far better with low water temps than fin-tube baseboard will.
With a mod/con boiler, lower return water temps produce higher combustion efficiency. Lower firing rates (burner modulating down) also produce higher combustion efficiency. Condensation happens as a side effect of this higher efficiency. There is no "quantum leap" when condensation starts -- but instead, a continuum of roughly 86% to 98% depending on the conditions above.
@ March 6, 2014 10:52 AM in Rinnai RH180 or 100 Gallon Atmospheric?I'm curious about the piping layout you used to accomplish the switching.
@ March 6, 2014 10:50 AM in Free solar ???????http://en.wikipedia.org/wiki/Power_purchase_agreement Not all states have enabling legislation yet.
@ March 6, 2014 10:15 AM in computer room heat gain questionAre not simply a multiplier of volts and amps. There's a phase angle component (called power factor) which requires sampling over time and averaging. Your meter will work fine for stable DC, but will not give you the right answer -- especially for nonlinear AC loads like a computer power supply.
@ March 5, 2014 1:33 PM in New Boiler PipingsGenerally agree, especially when the envelope has been improved to the point where lower fluid temps will satisfy on a design day.
There are still a few cases where it makes sense. Fin-tube baseboard sized at 170ºF (or higher) comes to mind, along with the modified iron alloys used by Viessmann and U.S. Boiler (which tolerate lower return temps.)
@ March 5, 2014 1:12 PM in Got my Sorbox today.As near as I can tell "Nut G" is one of several names for an ISO coupling/union standard.
In North America, some manufacturers call it BSP. Other manufacturers (Uponor comes to mind) use "R32." Aquatherm and LK Armatur use the term "Nut G." Caleffi calls them "1 inch union." I haven't test fitted enough of these to be sure that they all fit perfectly, but I would truly love to have a definitive guide someplace.
@ March 5, 2014 12:57 PM in Fuel use question?322 gallons X 91,500 BTU per gallon / 1400 degree-days / 3,400 square feet
@ March 5, 2014 11:16 AM in Got my Sorbox today.of the coupling? I can't tell much from the manual PDF.
NPT will certainly work here and can be sold without need for instruction, but options for other piping systems are a good idea. If the device happens to have "Nut G" connections there are options in most of those already.
@ March 5, 2014 11:09 AM in Fuel use question?is BTUs per square foot per degree-day. I get 6.19 using your monthly figures.
@ March 5, 2014 10:55 AM in Gas furnace v hydro-air in remodelSince you're adding on, you might consider adding some radiant emitters to increase comfort and reduce the winter CFM requirement.
@ March 5, 2014 10:42 AM in geothermal vs. airsourcebut there are places (e.g. Las Vegas, Nevada) where GSHP's simply don't work after awhile. The interactions of soil moisture, groundwater movement, and heat transfer to/from the atmosphere are way beyond my pay grade, but I'd settle for a survey of existing systems to see what has happened after 10+ years of use. In the systems I have looked at, problems were always attributable to poor design, poor implementation, or inadequate maintenance.
@ March 5, 2014 10:27 AM in computer room heat gain questionon the type and age of the computers and monitors. Serious performance machines for CAD or gaming can easily draw 300+ Watts, while newer generation basic desktops under 50W. Spend $25 on a Kill-A-Watt meter and find out for sure.
@ March 4, 2014 7:55 PM in geothermal vs. airsourceRoughly equal heating and cooling loads increase the viability and longevity of most ground-source heat pump installations. If the two are widely disparate, a heat or cold plume can build up, which slowly reduces COP over time. With sufficient groundwater movement, the problem is masked when the plume shifts to someone else's land.
@ March 4, 2014 2:54 PM in Carlin Gas Conversion or new oil tank?natural gas heat should make the property more attractive to potential buyers. With all the oil liability issues and associated MA regulation, the appraisal should also benefit.
@ March 3, 2014 11:09 AM in Unequal circulators in seriesof two pumps in series, unless conditions require one pump some of the time and both at other times. Is the head so high that no single pump will do the job? That's another valid application.
I would think the labor to plumb, mount, and wire an additional pump would exceed the cost of simply replacing the existing pump with one of the proper size.
@ March 3, 2014 9:26 AM in htp boiler 0-10 signalare more common Europe, and (as a result) for the onboard controls of many domestic mod/con manufacturers (specifically those made by Honeywell Europe. Most domestic controls suppliers do not stock them, but the parts houses do
@ March 3, 2014 9:10 AM in Hydronic off new DHW for BasementGiven the topic, your post would probably get more eyeballs in the Main Wall.
Do you have a heat loss calculation for the house, especially the basement? Is the basement occupied regularly or intermittently? Is there insulation under the slab?
@ March 2, 2014 9:38 PM in Unequal circulators in seriesis for drainback solar in a multi-story building.
@ March 2, 2014 7:38 PM in Pictures of existing system that needs replacementFirefox 27 on Mac OS X.
@ March 2, 2014 7:20 PM in htp boiler 0-10 signalI'm not familiar enough with the Pioneer to know offhand what it uses for OAT. SWT is a 10k Type 3 (common as dirt.) Whatever it is, I'll bet JCI can get you a replacement for under $10.
@ March 2, 2014 7:10 PM in noisy slab sytemis on the inlet side of the pump? And the outlet feeds all five loops in parallel?
300' of SDR9 PEX flowing 1 GPM with 80ºF water presents 10.8 feet of friction head. At 120ºF the number drops to about 10 feet. If your loop lengths are accurate and the embedded PEX did not get crushed or kinked during installation (or during the slab pour) it's probably the tankless HX. What make and model is the tankless?