Security Seal Facebook Twitter GooglePlus Pinterest Newsletter Sign-up
The Wall


Joined on November 26, 2011

Last Post on August 30, 2014

Contact User

Recent Posts

1 2 3 4 5 ... 151 »

Tankless electric

@ August 30, 2014 1:52 PM in Waiting for hot water to shave

will work if conditions are right -- pay attention to the minimum water temp after a long period of non-use.  Demand-based recirc will also work using something like

Room-by-room heat loss calc first

@ August 28, 2014 2:21 PM in Heating dilemma: Recessed radiator vs cast iron baseboard

then measure all the recesses.  If the original system was hot water, you should be able to size modern plate radiators to fit.  They are surprisingly affordable and quite unobtrusive.

Cost differential

@ August 25, 2014 12:38 PM in Big Changes for Duct Testing in MA

may actually help us in selling radiant :)

Big Changes for Duct Testing in MA

@ August 25, 2014 10:43 AM in Big Changes for Duct Testing in MA


If you have not been asked to complete a duct test by your local
Massachusetts Inspector, it is just a matter of time before you are
surprised by this stringent/updated code
requirement.  Despite some push-back from Contractors  and Inspectors,
all of MA is required to test new or altered duct systems.  All of MA
adopted the 2012 International Energy Conservation Code (IECC), enforced
as of August 16, 2014.

Define the requirements first

@ August 23, 2014 8:51 PM in puchasing a new ammeter, recommendations?

Do you need to measure DC amps as well as AC using the clamp?

What is the highest current you need to measure, and in what size wire(s) would that be carried?

What is the lowest current you need to measure?

How important are voltage and resistance measurements for this meter, and as above, how high and how low?

8 feet of head

@ August 23, 2014 8:40 PM in rework closed loop to drainback

is right on the edge for a Laing Thermotech D5

You might consider two indirects

@ August 22, 2014 9:47 AM in Should we use new steam boiler for hot water heating?

one for each boiler.  That would separate the two gas bills while providing more hot water for each unit and (if properly installed and maintained) should have several times the lifespan of a typical tank heater.


@ August 21, 2014 3:21 PM in System's Architect

One of the few places I didn't look.


@ August 21, 2014 12:49 PM in Hydronic Baseboard Altitude Derate?

often have to argue with interior designers, once the baseboard limitations to furniture layout are brought up.  The winner is radiant ceilings, budgets permitting.

Take a look

@ August 21, 2014 12:02 PM in Hydronic Baseboard Altitude Derate?

at panel radiators, perhaps?

Indirect sizing

@ August 21, 2014 11:55 AM in Is 100k BTU the right size of boiler (or HTP heater) for both baseboard heating and indirect DHW

should you elect to take that route, can be calculated based on fixtures and use patterns in the house.

Assuming the existing TWH fires at 40,000 BTU/hr, it will deliver at most 32,000 BTU/hr into the water.  Continuous output will be higher with the new setup even with a 30 gallon indirect.  First hour requirements may dictate a larger tank (or not.)  No soaker tub there?

BSC alternative proposal

@ August 21, 2014 11:42 AM in System's Architect

Do you happen to have a link to this?

Can't seem to find it with and there is a nice discussion here but they BSC has a LOT of info.



@ August 20, 2014 4:15 PM in System's Architect

I have been following along for awhile now, and I have to say I disagree with their latest numbers (at least with regards to the houses we are building here.)  I suspect the uproar over 62.2-2013 will drive another revision, or at least some alternative methods.

Nice work

@ August 20, 2014 3:38 PM in Moline System in Moline, Illinois

Any pix of the original Moline bits by chance?

Fresh air

@ August 19, 2014 11:33 AM in System's Architect

has become a major focus in the past decade or so and is not to going away any time soon.  The ROI for HRVs and ERVs is quite dependent on climate from what I have seen, and for most of the Intermountain West they are a tough sell.  Continuously exhausting 100 or so CFM from a house (about what we need for most radiant jobs) is just not a big enough hit to justify the added cost and complexity of an ERV once you add ductwork, filters, and controls.

Motorized windows seem to end up in expensive houses and hard-to-access commercial or retail spaces around here.

Fully programmable

@ August 19, 2014 9:39 AM in Programmable Automated Controls (PAC) for Integrated Systems

means that every aspect of their operation is driven by the code you write (or the objects you drag and drop from which the 4GL creates and compiles into something P-code-esque.)  The only real limits to what you can do are driven by available memory and CPU, and what kind of I/O is available.  That would be protocol and communications I/O as well as analog I/O.

An old T87 thermostat would qualify as user friendly, and could well win the design award over something far more complex.  Making modern digital electronics truly user friendly is a high art (and impresses me mightily when I come across it.)

Not sure which blog you refer to, but it's certainly possible I've been there.  The DDC platform I use would qualify as user friendly to a controls integrator, but not to a homeowner.  It needs dedicated development tools and a skilled operator in order to function at all, and is optimized for the HVAC-centric operations typical in commercial and industrial settings.  General purpose home automation is a scary market to me -- far too many big players competing with far too much cash and too many competing "standards" for my taste.

I'm still curious what you're really trying to accomplish here -- if it's truly a packaged systems approach to be sold to (or through) homebuilders, you may want to consider a bit of market analysis before you burn too much of that startup cash.  I'm involved with a couple of groups who are working that way who are spending more effort in finance, building code development, and zoning than any of us would ever have expected.  It's really tough to effect fundamental change to a system this big and this entrenched, and darn near impossible when we underprice energy through a pervasive network of hidden subsidies.

Direct Digital Control

@ August 18, 2014 7:18 PM in Programmable Automated Controls (PAC) for Integrated Systems

is the industry term for this, and the better systems feature fully programmable everything.

If you hired me to do this, I would use a BACnet platform from

If you want to do this yourself, you have a bit of a learning curve ahead of you but there are quite a few options.  You might take a look at

Assuming you intend to market this system to the public, you will want to simplify both the system design and the controls.  That's not always as easy as you might think, but it is a rewarding process.

Oversized mod/cons

@ August 18, 2014 2:21 PM in Is 100k BTU the right size of boiler (or HTP heater) for both baseboard heating and indirect DHW

short cycle just like an oversized conventional boiler.  Even though there is a bit more headroom thanks to modulation, a low minimum firing rate will lead to longer run times and a happier boiler.

ROI will always be longer with a small load.  The added comfort and safety a mod/con provides may be worth a few extra bucks even if the hard dollar payback is less than optimal.

The HTP designs add mass, which is great -- just wish they made one with a smaller burner.  I could sell a 60-80k model all day long around here.

Water chemistry depending, probably...

@ August 17, 2014 10:36 PM in open loop geotherm question

If the only major issue is hardness, then your assumptions are most likely correct.  Should that be the case, A couple of hose bibs and 3-way valves and some simple routine maintenance can easily resolve the issue.

And don't forget

@ August 17, 2014 1:38 PM in Is 100k BTU the right size of boiler (or HTP heater) for both baseboard heating and indirect DHW

that your 77 feet of baseboard will top out around 40,000 BTUs per hour no matter what boiler you install.

Do not add the DHW load to the heating load -- they rarely coincide with each other and the newer boilers handle the switchover and switchback seamlessly.  Any of the boilers I listed above will outperform your existing 50 gallon gas water heater using a 40 gallon indirect -- most would using a 30 gallon.

Automated windows, shades and blinds

@ August 16, 2014 6:45 PM in System's Architect

have come a long way in the past 30 years or so.  Prices are still fairly high -- north of $200 per operator last time I used them on a job.  With proper control they can really work wonders - opening first floor windows at night when the whole house fan turns on, directing evaporatively cooled air to specific rooms while keeping it out of others, and of course shading control.  Most run on small DC motors that only draw a few watts.  ECMs really make the most sense for high duty cycle applications like fans and pumps.

Demand start of pump

@ August 15, 2014 1:43 PM in TT Smart 80 & Prestige Solo 110 Summer Gas Usage

Can be triggered by a button press (on the way into the bathroom or kitchen) or using an occupancy sensor (easiest way is to power the pump from one of the light circuits and use the occ sensor to do both jobs at once, but there are other options as well.)  This way the pump only runs when you need it and shuts off once the aquastat trips.
1 2 3 4 5 ... 151 »