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Joined on November 26, 2011

Last Post on August 25, 2014

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thermostat should

@ February 19, 2013 1:52 AM in Infloor Radiant Heat issue

really be a high limit controller if the ODR is setup properly.  It should turn off the boiler when your fireplace or woodstove elevated the space temp a few degrees above the indoor setpoint.

works fine

@ February 19, 2013 1:49 AM in Air eliminators

when it's at or near the PoNPC.

find out why

@ February 19, 2013 1:47 AM in I'm feeling lost

the pitting is happening before you start changing parts.


@ February 17, 2013 11:12 AM in HDE a? on p/s on navien

in that PDF show closely spaced tees (whenever the LH is not shown) noted as Min 6"

I'm curious...

watch your rubber

@ February 16, 2013 11:41 PM in anyone using b100 biodiesel

NBR (Nitrile) seals or O-rings will be toast, along with pretty much every other conventional rubber used for in hoses, gaskets, etc.  PE & PP can weep a tiny bit over time, but they don't actually dissolve.  You need FPR (Viton) with anything richer than about B30.  The residual methanol in Biodiesel causes it to retain several times the water that petrodiesel does. This plus the somewhat aggressive nature of biodiesel can cause accelerated rusting of steel tanks.

CFPP and cloud point are both in the range of typical winter temps, so it's not a set-and-forget deal in many cases.

BTW, I'm a huge biodiesel fan.

circ control

@ February 16, 2013 11:29 PM in Varible Speed Controller For Wet Rotar Circulating Pump

I've used them to control boiler circs on DDC systems.  They cost a fraction of the adder Taco wants for a VDT or VSF.  I'd happily pony up for an ECM, but nobody makes one with curve that really matches the TT firetube HX heat loss.


@ February 16, 2013 11:17 PM in I'm feeling lost

sounds like it might be coming from the inside.  Time to cut out a section of pipe for analysis.

any comparisons

@ February 16, 2013 11:14 PM in Still manually drawing radiant loops?

with HydroniCAD from someone who has used both?



@ February 16, 2013 11:07 PM in Backflow preventer question

will do exactly that.  Once it's gone you should be fine unless it damaged the seat or the gasket (in which case you'd see a drip or a dribble.)  It's also possible the pivot/shaft/spring/something in the mechanism is borked, but working the valve open and shut a few times should suss that out.


@ February 16, 2013 3:25 PM in I'm feeling lost

on the inside?  What are your velocities like?  What about your water pH?

I haven't tried a BumbleBee yet

@ February 16, 2013 3:23 PM in How would you control a Bumblebee circulator in a pure TRV situation?

but I'm sure they have a way of dealing with it.  I just pinged Steve Thompson on this.

delta-T will work just fine

@ February 16, 2013 12:07 PM in How would you control a Bumblebee circulator in a pure TRV situation?

As the TRVs slow down the water flow through the radiators, the average return temperature will drop and the pump will slow down to supply less, maintaining ∆T.

depends on activity level

@ February 16, 2013 11:00 AM in how much BTU does a person give off

that's the board we're using

@ February 16, 2013 10:42 AM in Varible Speed Controller For Wet Rotar Circulating Pump

with 0-10V DDC outputs.  You can set a fixed rate with the DIP switches.

increasing comfort while reducing fuel use

@ February 16, 2013 10:28 AM in I'm feeling lost

is entirely do-able using outdoor reset control, but a fan coil (toe kick) may not blend well with baseboard.  Matching the radiation to the heat loss in each space will allow you to keep all the units comfortable while keeping overheated tenants from opening windows to manage their comfort.  I'd start there before I changed anything else.  If the future attic insulation covers all of the spaces, it will allow you to install a smaller high efficiency boiler which will run at reduced operating temperatures and save a LOT of fuel.

so height is not an issue

@ February 16, 2013 10:17 AM in Radiant Heat Questions

in the existing slab area?  That's unusual to say the least.  Adding height usually implies re-framing doors, raising electrical outlets and perhaps switches, and moving a few windows.

over the top of existing slab

@ February 16, 2013 2:09 AM in Radiant Heat Questions

Roth Panel or Raupanel are both pricey, but they deliver upward heat with little waste downward.  Depending on which you choose, you'll gain 3/4" to 1-1/4" there.

start by balancing the radiation

@ February 16, 2013 2:03 AM in I'm feeling lost

in those end units.  You could swap out the baseboard for high output base or low profile panel radiators.

Who pays for the heat?  Any tenant control over heat now?

Insulation under floors and in attic?  Any chance of furring out walls on either side to add some?

If the backflow is in the wrong place

@ February 15, 2013 5:13 PM in Vapor/vacuum questions

any vacuum at all will draw air into the system.

All of these are worth your time to read

@ February 15, 2013 5:09 PM in Sizing issue for replacement steam boiler for single pipe steam system;


@ February 15, 2013 1:29 AM in Heat loss, what size boiler do I need?

Design days typically represent 2-1/2% of the use case.  If your building has significant thermal mass you can probably move to a looser design day spec (there are several) or just be willing to tolerate 66F instead of 70F or whatever.  With a well-controlled modulating system (whatever the heat source) it will not be an issue.

and you can drop the π

@ February 15, 2013 1:18 AM in under size steam header

anytime you are comparing round pipes.  Squaring either D or R will give you the answer.
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