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Joined on November 26, 2011

Last Post on September 2, 2014

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@ February 20, 2013 8:56 PM in High efficincy steam heating boiler

is there a derating factor that I can use on an oil rating to give me an optimal gas capacity?


picture too small

@ February 20, 2013 12:09 PM in Valve on PRV

To see any detail?

ITT T99B anticipator setting

@ February 20, 2013 12:00 PM in ITT T99B anticipator setting

Can't seem to find a manual for one of these old beasts online - does anyone have a link or a PDF?

Printed on inside of cover:

Cat. No. T99BV303J
See S.D.I. for installation & operation
24 Volt max
.3 - .8 Amp.

I can measure the current easily enough, but not sure what to aim for with a generic scorched air furnace.  Right now the deadband is way too big - it overshoots setpoint by around 7F before shutting down.


@ February 20, 2013 10:54 AM in Yet another boiler selection question TT with built in DHW or indirect?

Certainly have a bit of a checkered past here in the US.  Hard water, low pH, or chlorides were death to earlier heat exchanger designs.  The overwhelming majority of SS was indeed 316L, with a few 304L and some aluminum.  I'd just as soon forget all of those now that I've worked with the TT design, which is really the only one I can recommend with the hard water we have in the west.  Oh, and Viessmann uses 316Ti.

Our current NG prices make for long ROI with smaller loads, and nobody makes a mod/con properly sized for a well-insulated little house.  I usually assume NG prices will double in the next few years.  A properly installed and maintained mod/con ought to provide 20+ years in my book.  40 sounds great on paper, and I have no doubt the Viessmann equipment will make it, but when I look at _any_ kind of high technology from the early 1970's I have to wonder.

Why mod/con?

@ February 19, 2013 11:04 PM in Yet another boiler selection question TT with built in DHW or indirect?

The cons of poorly implemented condensing have unfortunately come to dominate the public discussion here in the US.  Modulation actually accounts for more of the thermodynamic, economic, and environmental coolness.

ECM micro circs

@ February 19, 2013 8:45 PM in How would you control a Bumblebee circulator in a pure TRV situation?

are probably in our future.  There are a couple in the EU market but they aren't sold here.

I'm envisioning something that runs on 24 VAC and tops out around 2-3 Watts.  Small enough to mount on a manifold, internal ∆T control plus some kind of network connection.  Full BACnet or LON would be overkill here, but an inexpensive field bus akin to 1-wire that would allow control and monitoring would be great.  Imagine a smart micro LoadMatch...

To zone or not to zone

@ February 19, 2013 8:29 PM in Yet another boiler selection question TT with built in DHW or indirect?

When running outdoor reset, we do what could be called inverse zoning or off zones.  Any space which is subject to heating by other sources (most commonly solar gain or a woodstove) gets either a TRV or a stat and a zone valve.  Set the stat a couple degrees above the indoor design temp and it will prevent overheating.  You don't want to valve off more than about 30% of the load or there will be issues.

Why everyone doesn't just go with combi boilers

@ February 19, 2013 10:58 AM in Should we choose this boiler? CC125 125,000 BTU In/put 96,000 BTU Output Challenger Combo Boiler - Space Heating & Domestic Hot Water

A heating boiler needs to be sized for design day heat loss.  This allows for maximum turndown on a mod/con (or longer cycles on a conventional boiler.) These maximize comfort while increasing both efficiency and longevity.

An instantaneous water heater needs to be sized for peak domestic hot water demand.

An indirect water heater is sized based a combination of on first hour and continuous DHW demand.

It's unusual for these numbers to be close to each other.  A house with a 48k heat loss that needs 6 GPM of hot water at an 80F rise suffers from a 5:1 sizing discrepancy.  An indirect water heater can be sized to deliver what the occupants need while keeping the heating boiler at the proper size.  The overwhelming majority of tank water heaters deliver less than 30k BTU.  Even a 60k mod/con boiler will outperform that roughly 2:1 while saving at least 30% on fuel use for DHW.

respect due

@ February 19, 2013 10:38 AM in How would you control a Bumblebee circulator in a pure TRV situation?

Ack - major typo there (and it was mid-day!)  Fixed it - thanks :)

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
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