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Joined on November 26, 2011

Last Post on August 21, 2014

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CI rads that will produce 48,066

@ July 8, 2014 10:27 PM in Complete new system on small house

Using what water temperature?  More really is better when it comes to radiation.

Real-world savings

@ July 8, 2014 4:37 PM in Getting into mod/con business

> I'm speaking of the actual AFUE, which is not easily determined for a system.

> The actual AFUE is the only way of comparing the efficiency of one system to another system

AFUE is a computed value, and as many have mentioned here, not a particularly useful one.  The real-world annual energy savings is quite simple to compute, but it does require a couple of months of winter fuel usage.  Calculate the number of BTUs consumed and divide those by the number of heating degree days and you get something resembling the truth.  In my world the truth is a savings of 40% or better using the math I just described.  We tell customers to expect "at least 30%" and have yet to miss our mark.  When replacing older, oversized, improperly controlled systems we frequently see savings as high as 70%.

Start here

@ July 8, 2014 1:22 PM in Radiant cooling and you'll learn a lot.

Do the math

@ July 7, 2014 10:39 AM in Getting into mod/con business

because it's different for each region and even for individual utilities.  Out here NG currently costs under 70 cents per therm including fees and taxes.  With our short heating season and assuming a 15 year life on the mod/con, it's a tough sell for smaller houses -- but a no-brainer for commercial projects.  OTOH for customers on LPG, even a 60k design day load usually justifies one.

Radiant cooling controls

@ July 7, 2014 10:33 AM in Radiant cooling

take dewpoint into account.  With proper design and control strategies, you can remove most of the sensible heat using radiant, leaving you freedom to optimize the MUA and latent loads.

In the southwest, we can often skip dehumidification.  One afternoon last month we hit 95ºF with a dewpoint of 14ºF.  I've seen spreads over 20ºF bigger in Phoenix.

Speaking of Extech

@ July 6, 2014 11:34 AM in True RMS

I just have to put in a plug for their 380942 mini clamp meter.  I love my Fluke for higher power stuff, but the small jaw and high resolution of the Extech makes it perfect for a lot of troubleshooting tasks.

Water first for sure

@ July 5, 2014 2:09 AM in Cleaning radiant tubing

usually beginning with a street pressure flush (or crank up the Pressuretrol if they're on a well.)  Once you see clean water coming out of the drain(s) then move to the next step.

Try this

@ July 4, 2014 4:55 PM in Cleaning radiant tubing

They certainly are cute

@ July 4, 2014 3:18 PM in Low Profile Rescom 2100 Aluminum Baseboard Radiators

but they make you work to find the output capacity.  Here's a cleaned up version of the info p.7 of the installation instructions:

Test results have been adjusted to reflect a 15% radiant efficiency factor.
Data derived from factory tests February 1996. Complete test data available on request.

Selling & installing mod/con boilers

@ July 4, 2014 11:41 AM in Getting into mod/con business

you are about to embark on a relationship with a manufacturer that will last a decade or more.  Even if you decide to change horses in six months, you will still own the boilers you installed before you changed your mind.  You are smart to be asking about this before you jump into something.

Like several others here, I have had great experiences with both Triangle Tube and Viessmann.  Quality products, quality training, and they will be there for you when/if the going gets tough.  Rinnai sells a good product and has comprehensive training, but the price makes them a tough sell, at least in our market.  Lochinvar has very flexible onboard controls but has become somewhat of a commodity around here.

Modern modulating/condensing boilers only perform as advertised when they are properly applied, sized, installed, and commissioned.  They do not tolerate fools. In a sane world, these products would only be sold to qualified installers.  The unfortunate reality of our distribution system here in the US will quickly give any manufacturer who tries that the kiss of death.  The better manufacturers provide incentives to their trained installers (sometimes in the form of extended warranties) to try and give them an edge over the trunk slammers who buy their products out of distribution.

Window is on the top of the heat exchanger

@ July 3, 2014 7:27 PM in TT Smart 80 & Prestige Solo 110 Summer Gas Usage

You need to remove top jacket access panel (the rear half of the top cover) or find a moderately long dental mirror in order to see it.

Series Summation Method

@ July 3, 2014 1:19 PM in Bouncing Gas Pressure

Anyone know of software that supports this?

RMS is important

@ July 3, 2014 1:12 PM in RMS

When you measure any waveform that deviates from sinusoidal.  That would mean any time an inverter, a VFD, or a switchmode power supply is involved. 

Two is better than one by far

@ July 2, 2014 11:56 AM in Slab Sandwich

but I'd use a minimum of 2" insulation underneath - may even be a code requirement, but perhaps not in your climate zone.

The biggest thing is to make sure the tubing is tied to the top of the rebar, with the rebar on chairs -- keeping it in the upper half of the pour.

Sultana Tragedy

@ July 1, 2014 10:53 PM in Dans Reading List

An update aired tonight

The whole show is interesting.  The final 15 minutes helped me to frame American political corruption in perspective.


@ July 1, 2014 7:49 PM in New gas boiler sizing

YOUR local supply house is not in question here.

Referring a homeowner to THEIR local supply house is a complete crapshoot.  Qualified hydronics installers have unfortunately become somewhat rare in America.  The RPA is actively working to fix that, and a small handful of manufacturers are leading the way.

No disrespect here, but

@ July 1, 2014 5:38 PM in New gas boiler sizing

"your local supply house" may not have a clue about proper training and installation practices of their customers.  A few do, but the majority in my experience do not.  A "local boiler guy" won't cut it either.

RPA members generally have a clue -- I'd start there.  The ones they have actually trained know their stuff for sure.

The rep firms are better, especially for certain brands.  Viessmann and Triangle Tube come to mind as having well-rounded installer training programs.  Lochinvar makes a great product, but I have no direct experience with their training programs.

Sensor locations

@ July 1, 2014 9:43 AM in TT Smart 80 & Prestige Solo 110 Summer Gas Usage

are significant, as you have just witnessed firsthand.  Now that it's picking up an earlier signal, you might try increasing the differential a bit.


@ June 30, 2014 6:36 PM in Converting Oil to Gas

Somehow thought you had a steam system -- apologies.  For hot water heating, a new boiler will indeed be much more efficient.

A properly sized, installed, and commissioned modulating condensing boiler will save more fuel than the AFUE numbers would indicate.  If you convert your historical oil usage into Therms, you should save at least 30% in fuel BTUs with a new boiler.

Conversion burners

@ June 30, 2014 5:51 PM in Converting Oil to Gas

} She explained that I won't get the improved efficiency of a gas boiler vs. an oil boiler

Quite the opposite, with a properly sized and installed conversion burner.

Not sure if Charlie travels that far, but perhaps Tim knows a tech nearby who can handle the work.

Cause and effect

@ June 30, 2014 10:45 AM in TT Smart 80 & Prestige Solo 110 Summer Gas Usage

are inexorably intertwined here, and not really the point.

Let's assume for your particular location, weather, and fuel that condensation begins at one very specific temperature -- say 130ºF.  The efficiency difference between return temps of 129ºF (we'll call that condensing mode) and 131ºF (we'll call that non-condensing mode) would be almost immeasurable.  The curve is smooth and has a low slope.

ecocirc e3 Vario

@ June 29, 2014 6:33 PM in ECM circulators

Has a knob on the side -- just turn it to the speed you want (we dial in the ∆T we want) and leave it there.
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