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Joined on November 26, 2011

Last Post on April 20, 2014

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Old churches and high ceilings

@ April 5, 2014 1:33 PM in Add-on fans for old convectors

I don't believe the Methodists intended this one to be uncomfortable, but they did build it in a era of stupid cheap natural gas, so the boiler would pretty much chug away at full bore from mid-November through early May.

A few years back they added a row of ceiling fans down the middle of the building to aid in destratifying the air.  We're just trying to find a way speed up the recovery if we can.

I've got them starting on a radiation survey next week so we know what we have to work with.  First pass indicates we may be able to replace the existing two natural draft boilers (Burnham Holiday firing at 480k and a Peerless 211-5) with a single 399k mod/con, or perhaps a pair of 250's.

That might be the one

@ April 5, 2014 1:19 PM in Add-on fans for old convectors

some good info there in any case, should we decide to fabricate them.  We would control the speed via the DDC system to optimize comfort.

I've reached out to the Jaga folks to see if they will sell components.

Adding a tank

@ April 5, 2014 12:03 PM in Indirect or Combo Boiler with Recirc DHT?

allows the recirc to work without firing the tankless.  The tankless takes over as soon as flow increases to the point where its sensor tells it to fire.

The bottom line is that tankless water hears are not the be-all and end-all that the salesmen want you to believe.  They are fantastic at what they do, but for many customers a tank-type heater (especially an indirect) can actually be a better option.  The extreme ∆T conditions experienced by their heat exchangers is a poor match with hard water, most especially if they are not regularly maintained.  We recommend tankless when it makes sense and are big believers in them for the right application.

Yes, it's a retrofit

@ April 5, 2014 11:23 AM in Add-on fans for old convectors

in an old church.  Convectors along the sidewalls of the sanctuary, which typically only needs heat on Sundays.  Trying to bump up the recovery rate as we design the new boilers and controls.

I'm pretty sure I saw something with a row of ECM DC fans (like computer fans) that would fit in the case.  If not, I know some guys who can probably fabricate them.

Recirc complicates things quite a bit

@ April 5, 2014 10:52 AM in Indirect or Combo Boiler with Recirc DHT?

with the vast majority of tankless water heaters.  That's why Heatpro adds the baby electric tank -- to keep the tankless from short-cycling as the recirc line cools.

What I was suggesting is a variation on the European model, where you install an electric tankless near each point of use.  Our fuel costs are radically different here, especially with current NG prices.  On a per BTU basis, electric resistance costs 6X what NG does here, but I still recommend it for specific applications.  If the electric heat source only runs a few hours per month (filling a big tub) or even a few hours per year (backing up a solar DHW system) the reduced installation cost, maintenance, space requirements, and simplicity can easily trump that of a larger gas-fired heater.  Properly sizing the primary system will save on first costs, fuel, maintenance, and space requirements.  If a building has a remote bathroom or small kitchen in a guest house, an electric tankless can heat the water until hot water from the main heat source makes it down the line.  It only runs for a minute or so each time the faucet is opened, and drops out of the circuit as soon as it is not needed.

Consider your monthly use

@ April 4, 2014 10:39 PM in Indirect or Combo Boiler with Recirc DHT?

If you have something like a soaker tub that gets used once a week, it may make sense to install an electric tankless as a dedicated booster just for that load.

Even with a probe-type LWCO

@ April 4, 2014 10:26 PM in steam boiler maintenance

you should drain a bit from the mud leg every so often.  Maybe once or twice per season?

Range of sizes

@ April 4, 2014 5:17 PM in Add-on fans for old convectors

Roughly 3 feet to five feet in length.  They're recessed in the wall -- haven't pulled them apart yet, but I'd guess the fins might 4 inches or so.

Add-on fans for old convectors

@ April 4, 2014 4:34 PM in Add-on fans for old convectors

Anyone have a source for low-profile high efficiency fans that can be retrofitted to 1950's era wall convectors?  I vaguely recall seeing something here awhile back, but perhaps it was on another site.


NEC Article 110

@ April 4, 2014 11:24 AM in Bad hydronic panel install...

Working space

Box Elders

@ April 3, 2014 10:05 PM in Stinkbugs

used to be common around here.  Siberian Elms and Alianthus have beaten them pretty badly in most places.

Fire sprinkler calcs

@ April 3, 2014 10:25 AM in what is the maximuin water flow through 1 inch copper at 50 psi

are different, and definitely part of the engineer's job.  He can choose from a huge variety of heads, with a range of coverage patterns, flow rates and areas depending on pressure.  Is this a 13R job?  If not, you might consider what occupancies he is designing to and perhaps engaging the architect and/or the fire marshal to see if you can veer them off of 13, at least for the guest rooms.  I've done it and saved a pile of money.

I wonder if they know

@ April 3, 2014 10:10 AM in Nest for the UK

that installing a programmable thermostat (no matter how smart) on a radiator system with TRVs will hardly make things better.

Magnuson–Moss Warranty Act

@ April 2, 2014 9:21 AM in Burnham gas conversion

I've asked before for a reason this should not apply to boilers

The way it was explained to me (when I worked in a different industry) was that in the event of a claim, the burden of proof fell on the manufacturer (they had to either prove that the aftermarket part actually caused the failure or honor the warranty.)

Recirc pumps

@ April 1, 2014 11:24 AM in Indirect or Combo Boiler with Recirc DHT?

The 9U curve runs from about 9 feet to 12 GPM.  It consumes about 40 Watts.

The ecocirc e3-4 curve runs from about 5.5 feet to 5 GPM.  It consumes 2-10W at full speed -- even less if you buy the Vario version and turn it down.

The overwhelming majority of DHW recirc systems (both commercial and residential) we encounter are overpumped.  This makes some sense with a demand system, since the pump is only powered for a short time and you need the water to get there fast.  For continuous recirc or timed systems, it wastes a lot of both heat and electrical energy.

If the existing piping is copper, and especially if it increases to 3/4" as it nears the pump, you might consider reducing the size of accessible portions with PEX, perhaps even 3/8" from the individual branches.  I'd also look at balancing valves for the branches.  Don't forget lots of insulation.

Radiant gas

@ April 1, 2014 10:31 AM in Hydronic radiant heating subtleties

Yes, those are in the right family.  There are lots of options, in all sizes

Occupancy sensors

@ April 1, 2014 10:20 AM in Indirect or Combo Boiler with Recirc DHT?

are just one way to skin the cat.  You can add a single pole switch downstream of the occupancy sensor if needed.  Four baths and a kitchen is a different animal.  Home run 3/8" manifold systems are one answer, and you can mix those with recirc as long as you follow the rules (no recirc through the manifold, at least with the Manabloc.)

24 x 7 recirc works if you really minimize the flow with something like a B&G ecocirc e3 Vario.  If you install a "standard" recirc pump (003B or similar, or even worse, one of those 006B's they have on the shelf at the local supply house) you will consume much more of both electricity and gas.

Read up

@ April 1, 2014 10:07 AM in How To Make Current System More Efficient before you start buying parts.


@ April 1, 2014 10:02 AM in Rehau

is compatible with all PEX connector systems.

PEX-B is not compatible with expansion systems (F1960, F2080)

For reference:

  1. ASTM F876 Standard Specification for Crosslinked Polyethylene (PEX) Tubing
  2. ASTM F877 Standard Specification for Crosslinked Polyethylene (PEX) Plastic
    Hot- and Cold-Water Distribution Systems
  3. ASTM F1281 Standard Specification for Crosslinked Polyethylene/Aluminum/Crosslinked
    Polyethylene (PEX-AL-PEX) Pressure Pipe
  4. ASTM F1807 Standard Specification for Metal Insert Fittings Utilizing a Copper Crimp Ring
    for SDR9 Cross-linked Polyethylene (PEX) Tubing
  5. ASTM F1960 Standard Specification for Cold Expansion Fittings with PEX Reinforcing
    Rings for Use with Cross-linked Polyethylene (PEX) Tubing
  6. ASTM F2023 Standard Test Method for Evaluating the Oxidative Resistance of
    Cross-linked Polyethylene (PEX) Tubing and Systems to Hot Chlorinated Water.
  7. ASTM F2080 Standard Specification for Cold-Expansion Fittings with Metal Compression-Sleeves
    for Cross-linked Polyethylene (PEX) Pipe
  8. ASTM F2098 Standard Specification for Stainless Steel Clamps for Securing
    SDR9 Cross-linked Polyethylene (PEX) Tubing to Metal Insert Fitting

Waiting for water

@ March 31, 2014 6:59 PM in Indirect or Combo Boiler with Recirc DHT?

is not that long.  If you install an occupancy sensor for the bathroom light, you can wire the recirc pump to that and put a Taco 563-2 aquastat in series (which will stop the pump once the water arrives.)

VRV is big

@ March 31, 2014 5:53 PM in Hydronic radiant heating subtleties

commercial stuff, and I don't believe they have a radiant indoor unit for it.  I think the smallest outdoor unit is 6 tons.

For that patio, radiant would be by far the best option.  If you did the ceiling, you'd need to be absolutely certain the zone would never freeze, and I'd suggest something like a mechanical wall switch timer wired to the zone valve so it couldn't get left on.  Or you could just install a natural gas radiant garage-type heater out there.

PEX is fine

@ March 31, 2014 10:20 AM in Navien 240 combi installed - I have concerns

As long as it's sized and installed properly.  Underground, it's far better -- especially in acidic soil.  Watch out for the fittings and rings in that case.  ProPEX EP fittings and rings have higher flow and are immune to corrosion and dezincification.  You'll need PEX-A pipe to use them.
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