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Joined on August 25, 2009

Last Post on April 1, 2014

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Not on a combi

@ April 1, 2014 6:25 PM in Navien 240 combi installed - I have concerns

Domestic flow is through a plate heat exchanger so, pressure drop is minimal, maybe 5 psi at 5 GPM?

From an email

@ March 29, 2014 6:10 PM in Navien 100,000 btu heating

If you wish to view a recording of the webinar, you'll find it archived in Taco's "The Neighborhood," an online community for education and development. The Neighborhood requires a free, one-time registration that is separate from the Taco FloPro Team. You may join The Neighborhood by using this link:

You'll find this week's webinar, along with all of our past webinars, archived on the right hand side of the front page.

Watched Barbas webinar today

@ March 28, 2014 7:45 PM in Navien 100,000 btu heating

He pretty much explained today in his webinar using a lochinvar boiler with 5 GPM with a system requirement of 80,000 BTU's as an example how it works. Its not that hard to understand, and also realize not all boilers fire or operate on a 20 DT.
Heat emitter DT/BTU is different than boiler operation to understand heat transfer available.

No warranties

@ March 7, 2014 10:59 AM in NG Combi Boiler versus indirect tank and boiler setup

Per Naviens warranty and most other gas-fired equipment. If you buy online as there is no factory authorized online seller or retailer, the product warranty is voided.
Shows up broken, not working or have issues with install you lose and on your own.
Not worth it, go to a professional installer that stands behind the product.  


@ March 2, 2014 9:11 PM in Unequal circulators in series

I read or hear of these situations I picture 1,000 to 2000 foot radiant loops buried in concrete. Why? Because it usually is. "They told me to put 1,500' of tubing in the basement"

Check your manual for wiring diagram

@ February 24, 2014 11:55 AM in navien and odr?

Once you switch from constant operation to a input required you need a signal from the zone panel to enable the heat wired to the TT terminals of the NCB

Sometimes people need to learn a good lesson to share with others

@ February 18, 2014 4:50 PM in how prevalent is this?

1. When the 1,600 to 1,800 ft of 1/2" PEX doesn't meet the heat loss requirements
2. The tankless wont flow over 3 GPM with the piping setup, thereby restricting the PEX flow requirements
3. The limited flow of the tankless  wont give him the BTU's needed
4. His system is air locked filled with entrained air
5. He realizes hes taking a shower in odorous dangerous water that was sitting in the tubing
6. The excessive cycling on the tankless gives him far from expected operation efficieincy

Maybe after he discovers all that he can go back on the blog, admit his mistakes and offer to compensate all that followed his example with his millions?

Look to Canada for advances in combi use

@ February 18, 2014 10:48 AM in how prevalent is this?

They are developing a new standard (CSA P.9-11) that makes sense, we shall hear or see it soon or something similar in the states.
They do this stuff a lot in Canada with the small tight homes they live in.

Here's another one

@ February 17, 2014 11:04 PM in how prevalent is this?

Long but some good parts


@ February 17, 2014 1:50 PM in how prevalent is this?

Actually water heaters, tankless included as long as its used as a combi system is not illegal in most places for heating, and approved by the manufacturers.
Not that I agree, with the true combi boilers that are available today that segregate the two circuits, why do it? But you cant stop the tankless unit use in a combi application.
What I whole heartily don't agree with is a water heater applied to anything else but an air handler with a hydronic coil that has some built in protections such as higher heat operation and coil purging. Putting a water heater on a radiant system with all the added mass of stagnate water is asking for trouble, odors and dangerous exposures to potential illness.
Here's an interesting read though why tanks and tankless in combi applications can have their issues and not what they are expected to be:
BTW, that house looks to big to be heated with that number of loops, pipe size and tankless flow restriction.

Up to him

@ January 28, 2014 12:53 PM in How long in the shower?

Your welcome
Its his decision, install a different water saving head and then she complains about the time it takes to rinse right?
It comes down to is she a great tenant?
The cost of adding a second water heater to appease her is often easier than painting, cleaning carpets, updating items and looking for another good tenant.
Question is, who pays the gas? If I did I'd say get by girl, tenant pays, who cares right? It can be installed to isolate and drain for next tenant that doesn't want/need.

It depends Bill

@ January 27, 2014 7:04 PM in How long in the shower?

If it's a regulated housing unit such as in NY, department of housing states:

"Building owners are required to provide hot water 365 days per year at a constant minimum temperature of 120 degrees Fahrenheit."

That really means endless hot water.

Private rentals don't need to meet this requirement and it tends to be written in the lease as "adequate hot water"

For info, men tend to be 10 minutes or less, adult females 12-15 minutes and teenagers? Sometimes only after it goes cold.

Have your friend check the flow rate, maybe a shower head change can extend the time

check your power supply

@ January 16, 2014 10:06 AM in Very Unusual Honeywell Zone Valve Trouble

If you have 18 zone valves still, check your VA rating of the transformers
It can take 180 to 200 VA of a 24V system to open all those valves fully
Since a standard transformer is 40 VA with a suggested max of 4, maybe 5 H/W zone valves, are you coming up short?

I bet

@ January 13, 2014 10:31 AM in Navien CR240 help sought

on Sundays they have minimal staff and its busy because its cold.

Try again

@ January 13, 2014 10:15 AM in Navien CR240 help sought

The recall issued voluntarily was about the flue collar.
There was an upgrade kit that was offered several years back to upgrade some internal components, and the  installers were going out and doing this work. Too bad your original installer must not be on top of his game.
The number works, have the wrong one?
They can also often refer a service company I think

A condensing tankless would work

@ December 23, 2013 11:50 PM in Design-build hot water washdown

Say you use a 199,000, .95 EF, 96% thermal efficiency condensing tankless
Even at a 110 degree rise:

199,000 / 8.33 / 60 / 110 * .96 = 3.474 continuous GPM @ 110 degree rise


@ December 14, 2013 2:29 PM in What does

The K used in the Coefficient of thermal conductivity can be lower or upper case depending on how it's used in a equation.Is this all about promoting your recent publication Tim? Interesting read

1 W/(m.K) = 1 W/(m.oC) = 0.85984 kcal/(hr.m.oC) = 0.5779 Btu/(

Because I'm an engineer

@ December 12, 2013 9:13 PM in What does

KAIR = Thermal conductivity of air
Density, viscosity, humidity, barometric pressure and many other factors affect this


@ December 12, 2013 9:00 PM in What is the definition of

Makeup or compensating air is outside air which is introduced into the building to replace air that is exhausted from the building through ventilation or combustion processes.

A make up air unit will normally involve a mechanical means

Good math but need to adjust for boiler perimeters

@ December 3, 2013 5:13 PM in Navien ch 240

Btw chris I disagree about the condensate capturing of latent heat. That's the purpose of the down firing with the collector at the rear to reroute flue captured condensate to saturate the secondary heat exchanger.

For example similar in design to the tankless, they would not hit the 98% thermal- .97 & .98 EF the tankless is certified at.

What's left out of the equation above is the boilers actual fire rate and it's delta t. If fire rate is higher or set to overshoot set point higher, more heat (BTU) is transferred.

Anyways the AHRI certified ratings speak for themselves, it's not limited to 50,000 BTU's.

The replacement model is the NCB and it's available now

@ November 28, 2013 12:26 AM in Navien ch 240

Bob, it appears you don't fully understand injection with primary/secondary.
Even if the secondary boiler pump is 5 GPM, that doesn't limit the system primary flow and BTU's
Note the Viessmann 130,000 BTU is limited to 6 GPM boiler flow as another example.

And the CH doesn't fire on a 20 DT, the new one is also adjustable.

They once were

@ November 17, 2013 4:54 PM in Viessmann

They were on the list but cancelled their booth space 2-3 months ago?
I thought no big deal what will they show, combi maybe?

But the other big changes make me think it's runs deeper

Take Wilo for example, they haven't given up and are showing recent promise for fitting in.
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