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Joined on December 29, 2008

Last Post on April 23, 2014

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@ December 16, 2009 10:50 AM in Oxygen Diffusion

Once I changed out the circ and put in a new relief vlv on the indirect we had a 20 between indirect supply/return and boiler supply/return and it stopped relieving itself. I traced back the potable feed to the indirect. No backflows, checks or pressure red vlv at the meter. Water pres coming into the house was 75PSI.
Flue has been condensing since day 1. Caved in on the bottom right hand side. Oil company did a cleaning in July and you can see the brush marks still in the residue left in the flue. They should have atleast notified the homeowner. Funny thing is that this has been an issue with the indirect since original install. Seems like the burner isn't very hot. Flame was like a campfire yellow, very wide and stringy. Nozzle was .75 x 60B as per the Reillo Spec for the boiler. Air set up for 3.1 as per the spec. Since day one this boiler has been running a 300 degree stack.

Question is

@ December 16, 2009 8:38 AM in need some math help?

what would my delta-t be?

8.33x60xdelt-t divided by btu output = gpm
On a 20 degree delta-t to deliver 10gpm I would need 100,000 btu's
On a 30 degree delta-t to deliver 10gpm I would need 150,000 btu's

All of You

@ December 16, 2009 8:05 AM in What makes the wall different.

Each and every professioanl here makes this site unlike any other. There are great minds that post and there are great minds that read. This is a who's who of industry books wrapped in one place. You can't find that anywhere on the internet.

Oxygen Diffusion

@ December 16, 2009 7:07 AM in Oxygen Diffusion

I recevied a phone call yesterday from a good customer who was at his Uncles house and couldn't figure out the problem. His Uncle called him because the relief vlv on the indirect would continue to blow, the boiler according to the tridicator couldn't get above 165 and he was stomped as stumped could be. When the indirect called and the boiler fired the tridicator temp would actually head left instead of right.  The job is just a simple two zone heating and a zone for the indirect. No priority. Piping is the standard antler nothing wrong with any piping. Zoned with zone valves. Boiler is  a Weil WGO-3 w/Reillo F5 burner.

When I got there we fired up the boiler and opened the indirect zone. Couldn't get a 20 degree delta-t. The boiler circ was running (you could hear it and feel it) and the tridicator temp was heading left.  As we shut down the boiler and started to ponder. I saw that one zone was  zoned with PEX tubing. This was down about 7 years ago and this run is well over 100'. I coudn't read the tubing as the writing was not visible. I grabbed small stool and climbed up to to read the backside of the tubing and low and behold it was plumbing pex.

After I explained to my customer the possible effects of oxygen diffusion so we decided to take out the circ. Oh my god! What a stink, smell coming out of that boiler,. like dead fish baking on a summers day at the dock. The circ was covered inside with a film of black as was the nipple coming out of the boiler. Took apart the zone valve and the same film. I also noticed on the side of the boiler that the stack temps since day one have been only 300 degrees. Took at the stack pipe and could see the right side of the masonary chimmney eating away and the pins on the iron covered in a hard white. Boiler was cleaned in July this year.

Question? What is the best way to clean out the boiler? Is it worth it? Same goes for the indirect. Do you think the reading on the tridicator are false do to covering of film?
Any suggestions would be appreciated. Customers uncle has very little dough. He is by himself. My suggestion was to put in a 50 electric htr for now and clean up the boiler and change the pex.

Post Pics

@ December 14, 2009 6:04 PM in Hot water will not flow from boiler to radiant installed floors

Posting some pics may help. There could be many reasons why no flow. Can you give us an idea of how the radiant is installed. Loop lengths, tubing size etc.

Try This

@ December 14, 2009 6:00 PM in Counting Section of Sunrad Recessed Radiator

It may help you out.

Taco ZVC

@ December 14, 2009 8:36 AM in Zone Valves & Taco Controller

You need a ZVC-404 for the acutator controls you need a SR relay for your circs. You can use the circ relay as the master and the zone relay as the slave. See page 13 of the attached wiring book. It shows a SR-501 and ZVC 406

Vitodens 100

@ December 14, 2009 8:08 AM in Modulation Range of Condensing Boilers?

Keep in mind that you would be using a LLH (low loss header). Boiler supply water temp max is 176 on the Vitodens 100 leaving the boiler to the LLH (when your curve is set to 6). You are only getting  roughly 170 degree water on the system side of the LLH. This is all based on a 20 degree delta-t and flow rates. So let's say you only need 37K or 3.7 GPM on the boiler side and your delivery water temp out the boiler is 115 degree water to the LLH. Water temp on the system side is going to be alot colder leaving the LLH probably 100 degrees or so. Board would be only putting out roughly 120 btu's a foot. I don't think short cycling will be an issue. The boiler is going to run as long as the zone thermostat asks the boiler to run. A perfect example of why the heat loss and emmiter sizing is key to  system efficiency.  Another way to combat is go to a 30 degree delta-t instead of a 20. Average water temp at design would be about 160and your board output at 1gpm and 160 water is about 430 btu's a ft.

Just my thoughts welcome to any others.

There is an Apartment

@ December 13, 2009 7:02 PM in Using a HW heater for a boiler

Complex that we send heaters to weekly to replace heaters that were used in this type of application. They are Bradford White MI-504's. They supply small air handlers and are also doing the domestic hot water. Average life of a water htr. 6-10 yrs. None of the heaters replaced are in the warranty period

Couldn't Agree with you more Tim

@ December 13, 2009 5:05 PM in Modulation Range of Condensing Boilers?

I have always taking the stand that system efficiency is more important than boiler efficiency. How an appliance makes its energy is great but how you use the energy produced from the fuel you pay for is most important. This is the main reason that I am a big Viessmann fan. They take a system approach with their products unlike any other boiler manufacture in the world.


@ December 13, 2009 4:33 PM in I'm a Grandpa!

The book of life opens another chapter. Enjoy the reading.

Bigger is Better

@ December 13, 2009 4:21 PM in 2" pex for radiant heat

I don't agree. Should have asked him if he was increasing the size of his heating appliance to keep up heating all that nice cold water that is coming back to the boiler or increasing his pumps for all that increased head? Bigger is better right?

Get a couple

@ December 13, 2009 7:29 AM in Tankless with hydronic heating coil

Of more estimates. I would start at SpacePak's web site. Check to see who they have in your area that installs and is familiar with their product. A phone call to them wouldn't hurt either. Most of my customers who install this type of high velocity system also specialize in radiant heat, mod/cons and other aspects of high efficiency heating. I'm sure your area has the same type of contractors. You should also do the same by getting in contact with Triangle and find out what contractors in your area have been factory trained. Penny wise starts with good planning and getting yourself the basic knowledge to ask the right questions. An estimate is an interview process and you should treat it as such. Check references.

Yes and Yes

@ December 12, 2009 9:41 AM in European style panel radiators and cast iron on same zone?

You can combine them. As the othe poster suggested towel wamers give  a bathroom a nice look at can heat the space provided they are properly sized. Whomeves panel rads you are looking at have correction factor charts to size the rads accoording to the heat loss and water temps you are trying to run.
You state that the manufacture says it can be done. Did you ask them for a contractor or wholesaler in your area that installs/sells their products? I would and get a second opinion. Ultimatly you live in the house and it's your comfort and decision on what you want installed not the contractors. If he can't do it find a qualified contractor that can.

I agree with You Scott

@ December 11, 2009 6:54 PM in 2 zone, prim/sec piping, one zone must have constant circulation.

On your thoughts. As designers/installers do we not always have to size our systems based on worst case using our heat loss and design parameters? I see everyday more and more mod/cons going in without heat losses and it's going to bite back.
Let's take primary/secondary piping for instance and using the typical 20 degree delta-t. Just about everyone installing mod/cons is using this piping arrangement.
We have a system with a heat loss of 50,000 btu's (5gpm), it has 3 zones with zone valves. Zone 1 has a load of 25,000 btu's (2.5gpm), Zone 2 15,000 btus (1.5GPM) and zone 3 10,000 btu's (1gpm). How do you size the baseboard for each zone?
I size it this way and it is based on all zones calling on my design day (worst case). I have a system flow rate of 5GPM and I hit the first zone. 180 degree water enters at 2.5pgm leaving me 2.5GPM of 180 degree water in between my tees before that zone returns. Water enters the return at 160 degrees at 2.5GPM leaving me a water temp before I enter zone 2 of (2.5x180) + (2.5x160) divided by 5 = 170 degree water at 5GPM. Now, 170 degree water enters zone 2 at 1.5gpm leaving me with 3.5gpm of 170 degree water in between my tees before the second zone returns it's 1.5gpm of 150 degree water. After doing the same calculations I have 164 degree water at 5gpm flowing towards zone 3. I enter zone 3 with my 164 degree water at 1gpm leaving me 4gpm of 164 degree water in between my tees headed toward  zone 3 return. I now have 1gm of 144 degree water returing from zone 3. Using the same formula it gives me my return boiler water temp of 160 degrees.

Each baseboard zone must be sized individually not as a whole. In this case.
Zone 1 Baseboard btu output is 581 per ft so I need 43 feet of board
Zone 2 Baseboard btu output is 508 per ft so I need 30 feet of board
Zone 3 Baseboard btu output is 460 per ft so I need 25 feet of board
Hope this makes sense.


Do Your Homework

@ December 11, 2009 6:04 PM in Tankless with hydronic heating coil

Not being familiar with the model you posted I went to the web site. After reviewing this unit I have a couple of questions. Are you using the MCC-91 control as per the manufacturer for hydronic heating. Also, the flow rate chart listed in the specs is based on a 50PSI system pressure, a heating system runs at 12PSI so the question becomes. Can you deliver the proper flow rate/gpm to overcome the heatloss. I have also attached the specs on SpacePak hydronic coils. My last question is this. You have to weigh this in your mind. What is the cost of the Rinnai Unit with the control compared to the cost of a condensing boiler? Why? The warranty on the unit  you are speaking of is only 5yrs.


@ December 9, 2009 6:15 PM in Boiler Wiring Question

Boiler and system is 40 years old. Is it really worth even thinking about a fix? My advice, do a heat loss, plan a replacement strategy.

Radiant Flow Rate

@ December 9, 2009 6:50 AM in Delta T

We like to run a 10 degree delta-t across the radiant zone. Keeps the floors evenly heated. If you run a larger delta-t the floors run uneven. For example if I ran 120 degree water and was returning at 90 then my average water temp through the floor could be 105. 105 may not be enough to heat on your design day. Also, keep in mind that your flow rates change significantly.. Let's say you need 10,000 btu's and you run a 30 that means you would have a flow rate of less than 1gpm. To accomplish this you would most likely have to use a pump like a Grundfos Alpha. If you mod/con is your mixing then why worry about the delta-t? It's condensing from the get go already. You should be focused on your comfort.


@ December 9, 2009 6:42 AM in Radiant Controls

You should be fine with using the reset  provided you punch in the correct water temp numbers you need at zero. Burnham recently announed a chage in the control for the boiler. The control is called the Sage2 and was being put on all the boilers as of Nov 2nd. Make sure yours is the new version. They are no longer using the MCBA control. The new control will be able to run a second water temp.

Types of Pex Tubing

@ December 8, 2009 7:15 PM in Pex Tubing

Sprinter I don't know if there is a best pex. I feel the tubing itself no matter what brand will out live all of us.

There are 3 methods in which pex is made. The method classifies the tubings designation as  PEX-A, PEX-B or PEX-C. This doesn't mean A is better than B or B is better than C.
I tend not to get caught up in the fitting so much with radiant. My feeling is that you should have no fittings in your loops and they should leave and arrive to the manifold clean. Most manifolds also use a compression style fitting to attach the tubing to the manifold. I prefer PEX-A as it gives me the ability to get a kink out without having to cut a coupling in and tends to be more flexible and easier to pull.

What else is the

@ December 7, 2009 5:33 PM in Radiant Controls

Boiler doing. Domestic Hot Water? Any baseboard  zones? How is the radiant attached to the subfloor? Also, Burnham just recently announced a new control strategy for this boiler. Does the boiler that you plan on installing have the new control package or the old?

Clammy makes a nice Case

@ December 7, 2009 5:27 PM in Convert apt. bldg to HW?

And I like his approach. Panel rads are not as expensive as most think. They will also cut down on some labor and you may be able to run 3/8" pex to them. You would also have more control as your tenants wouldn't have the luxory of turning up a t-stat on you. They will also use less wall space and give you the benefit of both convection and radiant heat.  They work real well with a mod/con if that is the direction you would like to go. Check out [url=] there is a load of info on low temperature hydronics and panel type radiators.

As for mod/cons. Stay away from alum blocks and your choice should be based on which contractor you choose and what he is most comfortable with. Yes Viessmann is my choice for mod/con but others out there will do the job just fine.