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Joined on January 19, 2012

Last Post on September 2, 2014

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@ August 4, 2014 3:20 PM in Reconnect oil boiler after copper ransack

Furnaces heat air.
You have a boiler with a tankless coil.
The flow control on the DHW side is installed so that you do not have a higher flow rate than the coil can handle. You may or may not need that one.
Between the domestic water in the house and the closed boiler loop you need an assembly that will reduce the pressure and prevent the potentially toxic boiler water from entering your drinking water. They look like this


@ August 4, 2014 2:45 PM in Reconnect oil boiler after copper ransack

You do not have a furnace you have a boiler.

The parts you are looking at are not the ones you need. Home depot does not carry boiler parts. The guy in the orange vest does not know anything about boilers.

You really need professional help with this one.

Demand Meter

@ August 3, 2014 5:15 PM in Electric Boiler and short cycling

In addition to SWEI's response,
On premises that are "Demand Metered", is is a good idea to have multiple elements and stage them. Bang Bang thermostats with leave you with very high demand spikes which will raise your rates.

Higher return?

@ August 3, 2014 10:55 AM in Condensing cast iron?

Raising the return gets the boiler out of condensing zone and greatly reduces the efficiency.
Why bother spending extra money for the HE model?


@ August 2, 2014 10:27 PM in Micro-load Dilemma: Add Storage or Nuclear Option

It looks like putting your 40 gallon tank in series will make your on cycles about 16 minutes.


@ August 2, 2014 5:53 PM in Micro-load Dilemma: Add Storage or Nuclear Option

If you know your system water volume and mass and the on/off differential on the boiler you can make an accurate estimate on the buffer tanks impact on boiler cycles. A quick look says they will get about 8x longer with a 40 gal tank.

The cocktails are also a good idea.

I don't think the average tech is quite ready for nuclear yet... 


@ August 2, 2014 5:47 PM in Condensing cast iron?

It looks like they are doing it with a secondary heat exchanger.
The KN-2 had an AFUE of 92.7% under the old rules. It looks like 90% under the new rules.


@ July 30, 2014 5:47 PM in Pool heating

You normally see them piped in series with the filter. They just use the pool recirc pump to move the water.
A flat plate HEX will have a fairly high head loss and is prone to gumming up.
You might look at something like a Triangle Tube Maxi-flo.


@ July 29, 2014 8:15 AM in Oversizing hot water baseboard for efficiency?

What you are suggesting is true and a good idea. Keep in mind that to maximize the efficiency, you really need a condensing boiler. Running a conventional boiler at low temps will not increase efficiency much and will shorten it's life.
Be sure to do a heatloss calc and design each room for your target water temp. Piping base board in series, as is often done, will reduce the output of the downstream radiators. This should be factored into the sizing.

Getting there...

@ July 28, 2014 8:49 AM in Boiler Room Layout Mock-up – reasonable, flawed or both?

You approach looks good. Take at look at the attachment for some minimum clearances.
Be sure to check valves at the boiler and DHW circs. You will want isolation valves on almost everything.
You might look into a combination hydrolic separator/ air eliminator. They are nice units and will save some space.
Do you have a plan to purge this? You will need a combination of boiler drains and valves that will allow you to "power purge" using the fill valve. You will also need to have the ability to pump in glycol or other additives if needed.


@ July 25, 2014 8:59 AM in Radiant Heat Matrix Other Than Concrete.

The tanks sounds great! You really need to insulate it.
I am still in favor of a combo solar absorbing/emitting feature in the green house. I think a heat loss calc and some calculations of potential emitting surfaces is needed.  You need to store water in the tank at a higher temp, giving up the heat to the ground does not make sense.

Flow or temp

@ July 24, 2014 2:46 PM in Lochinvar sheild HIgh limit problem

Having the setpoint to close to the high limit temp could be causing the issue.
Is the circulator working properly?
Does the boiler have a postpurge circulator setting?

New Thread

@ July 24, 2014 2:42 PM in NG Combi Boiler versus indirect tank and boiler setup

You will get better answers if you start a new thread...

Something for nothing...

@ July 24, 2014 9:29 AM in Want to move from oil to gas boiler. Best way forward?

I completely agree with you about the need for more buffer and storage in these systems.
Companies like Navien will always sell product to their customer base.
There are people out there that insist that you can get something for nothing. The navien is irresistible to folks with that mindset. Just don't try to confuse them with all this talkabout quality, mass, buffer, short cycling of gas line sizing. The Navien costs less, has a high efficiency sticker on it and makes the house and hot water warm (usually) end of story.


@ July 24, 2014 9:17 AM in Tubing size, spacing, flow rate for a joist install

It looks like you may need to raise your temps into the 120-130 range.
Not a big deal. Keep the loops short ans you should be fine.

Freeze protection

@ July 23, 2014 9:17 AM in Suggestions wanted

If it turns out you need freeze protection, You could have a seperate control that would turn the OWB circ back on if the water drops below 50 degrees and then off of it goes over say 70 degrees. If this was wired in parallel with the other control, it would give freeze protection without wasting as much heat or confusing the primary control into thinking the  OW boiler if firing.


@ July 23, 2014 8:43 AM in Suggestions wanted

The way I see it you have 2 problems.
The first problem is inadequate flow to the OWB. I agree that 9 gpm should be your target. Assuming that your indirect has fairly low resistance (not an amtrol) here is about what you will see:
Taco 007                4.4gpm
Taco 0014              6.63gpm
Taco 0013              8.34gpm
Grundfos 26-99    7.8gpm

The other problem is the piping/control arrangement.
Since the boilers are piped in series, when either is firing, it is wasting heat through the other. If you don't have glycol in the outdoor boiler, you may need this setup to prevent the outdoor boiler from freezing when on vacation and the OWB is not firing. If you don't need to keep the outdoor boiler warm using the indoor boiler, it would be pretty simple to install an aquastat and a DT/DT relay that would only allow the indoor boiler to fire if the outdoor boiler is cold. You would simultaneously turn on the indoor boiler and turn off the circ to the outdoor boiler. Problem solved...


@ July 22, 2014 11:46 AM in Tubing size, spacing, flow rate for a joist install

You will want to determine the required BTU output per square foot in each room.You will also need to know the design water temp your system is running the coldest design day.
If you use 1/2" tubing and keep the lengths around 200', you should be able to acheive your design flow rate fairly easily.

Some sort of aluminum track will be needed. Here is some good info from uponer.


@ July 21, 2014 8:00 PM in Electric Baseboard Vs Hydronic Electric Baseboards

The only advantage see is that they will more evenly and perhaps more quietly. I don't see how they can run at a lower temp as the overall wattage an size is very similar.

I know you are just looking for the answer to the question you have asked.
I would also suggest radiant cove heat for the reasons suggested above.

What is the reasoning behind the honeywell system? It looks like a major pain!


@ July 21, 2014 5:35 PM in Radiant Heat Matrix Other Than Concrete.

It sounds like an interesting project.
Have you considered turning a wall of the greenhouse into a solar collector by day and  radiant heater at night? Greenhouses are usually way to hot in the daytime and cool rapidly at night. If you built a wall using pex and aluminum radiant plates and paint it  black  you could store the excess energy in your tank and pump it back at night.


@ July 17, 2014 10:55 PM in Runtal towel warmer connection

This post may give you some insight

Good point...

@ July 17, 2014 7:54 AM in Constantly purging air in hydronic system

Mike makes a good point. At the end of the day, where is the air coming from?
Low system pressure is a likely one.
Is the pressure relief valve dripping?
What happens if you turn off the fill valve?
I think the tank corrosion Mike is talking about would not occur in a truly closed system with no leaks.
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