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Joined on January 19, 2012

Last Post on July 21, 2014

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I'll take the picture on the right.

@ August 13, 2013 7:33 PM in Primary / Secondary Basics

I'm not sure what you mean by "slinky" and "ferris wheel".
You have it piped backwards.

Condensing boiler

@ August 13, 2013 6:42 PM in Proper Operating Temperature for Weil-Mclain boiler

The way you have your system set, you are causing condensation in a non-condensing boiler. The condensate is acidic and will eat the boiler and flue pipe.
You are correct that you should run as low a temp as possible in your tubing. Running lower temps will also  lead to greater comfort as the system will only heat the floor as needed and will overshoot your indoor temp less often.
I would suggest a mixing setup with outdoor reset.
If you elect to not upgrade, set your boiler so that your return water temps are greater than 140.


@ August 13, 2013 8:19 AM in pump control wood heat

Just get an aquastat with both N/O and N/C terminals. It will close the circuit under the conditions you desire. 


@ August 12, 2013 11:39 PM in Radiant Heat not Heating

Without a drawing or a wider view it is hard to tell what is going on in your boiler room. I agree with J star that there are some things that look suspect.
One 3/4" tube every 16 inch does not make for much of an emitter. Is it stapled or hanging? Does it have plates or fins on it? I would guess that a bare tube assembly like that would have trouble making more than 10 btu/ft. I imagine your house loses more than that.
Have someone do a heat loss calculation and add the appropriate emitters. Panel radiators come to mind.

My Point

@ August 9, 2013 7:01 PM in Converting from oil to natural gas - Navien CH210 was recommended

I absolutely agree that we shouldn't size boilers by available radiation or existing size. I was trying to let the OP see for himself that his present boiler is clearly over sized.

There are a ton of different condensing boilers out there. Lumping them all together is is like saying you are not going to buy a Toyota because Yugo makes a bad car.

Buy a good condensing boiler and enjoy the comfort and efficiency they provide.



@ August 9, 2013 5:07 PM in Converting from oil to natural gas - Navien CH210 was recommended

Blindly replacing a boiler with the same size is not a good practice.
I wouldn't expect every contractor to a thorough heat loss on the first visit. It should be done before the project begins. I would expect them to determine the size of the house, lineal footage of baseboard and ask some questions about your hot water needs.

If you are curious, measure all you heaters and multiply your total footage by 600. This will give you the maximum amount of BTU's your house could possibly need.

The Navien is a lesser product than other condensing boilers. It comes at a lesser price.
Your call.



@ August 9, 2013 8:52 AM in DHW mixing valve and check valve requirements?

Some manufactures put integral check valves in the mixer. No need for another in that case.
Is long as the owner is OK with a little hot in the cold and cold in the hot, don't worry about it. I have found people have this crazy notion that when you turn the hot handle you get hot water and when you turn the cold handle you get cold. The other thing they like is once you set the temp to the shower it stays at that temp. They just don't like it if gets scalding hot when the washing machine downstairs turns on.
Seriously, if you don't have check valves, slight pressure differences in your system will cause cross flows that will annoy the owner and then, in turn, you.


@ August 8, 2013 11:58 PM in pipe ID and flow/BTUs

You have a reasonable amount of mass. Not great but workable. You can always use add some storage tanks later. You are not going to hurt the superstore with high temps.
How are you going to control it? The backup will heat the wood boiler when the wood fire goes out unless you do something.If you use wood 99% of the time it is not a big deal. I wouldn't elect to put the backup boiler in series as you have it as it just gives up heat and makes control more difficult.


@ August 8, 2013 9:35 PM in rarely

Paul,You have a condensing boiler with a very high efficiency rating. You only get that efficiency if you are returning cold water.  Check this out

The boiler will only fire to the temp calculated by the outdoor reset.
The warmer the day is the lower the temp you will have to run, the more efficient the boiler. No mixing involved.
As for the temp, it really depends on the design. I realize you don't have all the info.
Your high will likely be around 120.


@ August 8, 2013 6:51 PM in rarely

Maybe I am looking at the wrong install manual. Does your boiler have an outdoor sensor and reset capabilities? If so you don't need a mixing valve. It does not look like you need flow checks. Make sure you give yourself a way to purge the radiant loops and the boiler.

Great subject

@ August 8, 2013 4:20 PM in kill overheat with wood furnace

Hot Rod,
I have seen that too.
It was probably a good thing as the outdoor boiler had no glycol.
As for the OP, I think he was a "One Post Wonder"


@ August 8, 2013 2:22 PM in DHW mixing valve and check valve requirements?

The only check you have to install now are to protect against hot-cold, cold-hot cross connect. Some mixing valves have them built in.
The other check valves are an entirely different subject.


@ August 8, 2013 2:04 PM in Prevailing wage questions

Interesting stuff Charlie.
Reading through the list it really is just gauge of who has the stronger union. Tilesetter and masons are making 75% more than electricians?
No offense but this comes from the land of politically appointed toll collector making over 100K and A required policeman at every construction project near a roadway. Keep in mind he will never leave his car or attempt to direct traffic, he is just there to right you a ticket after you run over the workers.
Funny Stuff!


@ August 8, 2013 10:00 AM in pipe ID and flow/BTUs

The key with wood boilers is storage. They have no real ability to modulate so you have to be able to store the energy until you are ready for it. How much mass does the boiler have? How big is your superstore? If anything you want to add more mass, I would not eliminate the superstore without adding mass. I think it is unlikely the superstore is the problem.
As for you original question, go big!
BTU/Hr=gpm x delta t x 500.
It is hard to tell exactly what your gpm is right now because you are up on the top of the pump curve. I think it is likely 3 gpm +/-.
If you have a delta t of 20 that puts you at 30,000 btu presently. This is a serious SWAG, but gives you an idea.
If you went with an 1 1/4" pex (1" ID) with the correct circ, you would push about 11 GPM.That would give you 120,000. 1 1/2" at 15.6 GPM would be 156,000.
The wood boiler folks in their lust for sales don't share this stuff with you. It is the real math and is unavoidable.

Here it is...

@ August 7, 2013 8:25 PM in Gravity hot water heat

This whole section is super useful

You should still buy the book, it is very interesting.


Classic Hydronics

@ August 7, 2013 7:28 PM in Gravity hot water heat

I think classic hydronics has the most info on conversions.
One of the gurus on here posted some circulator sizing info in resources. I can't seem to find it right now.


@ August 7, 2013 1:52 PM in Converting from oil to natural gas - Navien CH210 was recommended

Go to "search the wall" and read all about it.
The navien subject has been beat to death on here.

Heat loss

@ August 5, 2013 6:15 PM in How much baseboard per room.

Step one- Do a heat loss calc. There are good free calculators on line.
Step two- Determine your boiler design temp. Conventional boilers will usually be around 170. With condensing boilers, the lower the better (max. 140).
Step 3-Look at the output chart from the heater manufacture and pick the size that matches your design temp and heat loss calc.

Chris beat me to it, Oh well

No arrow

@ August 5, 2013 2:47 PM in Is my hydronic system flow direction correct?

Usually they will have an arrow if they are directional.
When you put them in backwards they usually just "hammer" loudly/

In more ways than one...

@ August 5, 2013 11:47 AM in Is my hydronic system flow direction correct?

It looks like your boiler is piped backwards, the supply and return are usually the other way on a boiler of that type. You are also pumping into your expansion tank. This will account for all the air you are hearing. The air eliminator is a good idea. It will not work with the old school expansion tank. It looks like you have directional zone valves. Which way are they oriented? Are there other check valves in the system? Yes, you absolutely need a backflow/prv combo.
By the time you correct all this, you might ask yourself, "do I just replace the boiler?"


@ August 2, 2013 11:09 PM in Troubleshooting Prestige Excellence Lockouts

That boiler locks out around 10 psi. The fill valve is usually set to about 15#. You likely have a leak somewhere in the system and a fill valve that is not working quite right.
You immediate problem sounds like air lock. You can check that the eliminator on top of the boiler is open. To get more specific advise, you would have to post a picture.
I am out of town this weekend. There are much smarter folks on here that can help you out.


@ August 2, 2013 10:44 PM in Optimum flow for in-slab heating

We are talking about temp differences not actual temp
A temperature difference of 1°F is the equivalent of a temperature difference 0.556°C
 A temperature difference of 1 deg C is the equivalent of a temperature difference 1.8°F.
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