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Joined on March 28, 2011

Last Post on April 21, 2013

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Haven't lost interest

@ April 21, 2013 9:08 PM in Direct Pump TT Solo 110 with 3 zones

I was up at 4:00 A.M this morning drinking my coffee and reading the wall until 9:00 A.M.

I spent most of the day down in the basement running new copper for our domestic water supply. I have a Triangle Tube Solo 110 down in the basement sitting on a temporary wall. I wanted to get it down there and run gas and water in order to fire it up and run it for a bit. It had a cracked heat exchanger. I bought it used and replaced the heat exchanger. I wanted to make sure everything works, and it does. It was a gamble, but it worked out.

I have a way over-sized Slant-Fin (210,000 input) installed with a Unico hot water coil that was undersized (putting out about 60,000 btu). This was installed by a contractor who I now know was a forced air guy, and not a hydronics guy.

The Triangle Tube will eventually take the place of the Slant Fin, and the hot water coil will go away as well, replaced with cast iron radiators. I put in radiators for the first floor last October. I have radiators for the second floor sitting on the front porch. I have extensive structural repairs to make in the basement before I put the Triangle Tube in place for good.  In fact, I'm going to pull the Triangle Tube out of the basement before I start repairs. I'm rehabbing an 1888 house and there is fire damage in the basement that previous homeowners did not address, so I need to run new joists and pour footings and put in new posts and beams, then I'll put the boiler in for good.

I piped the near-boiler piping primary-secondary, but keep thinking about things. And wanted to see if there is some way I can make use of the Grundfos Alpha as the boiler pump. I was wondering about some things Chris has touched on in more than one post.

I think I'll be running constant circulation with ODR. My design temp is 130 degrees. I have the third floor that will not be used very often so I would still like to consider zoning in the future.

The cracked heat exchanger is in front. See the slight bulge?

If the following were assumed

@ April 18, 2013 4:17 PM in Direct Pump TT Solo 110 with 3 zones

- Zone valves.
- Well-balanced to match heat loss of each room.
- Minimum flow through boiler.
- ODR.

Can I really take advantage of a more sophisticated circulator such as the Grundfos Alpha, or shoudl I just get something that meets GPM and X ft. of head.

Why is direct-pumped better than primary-secondary?

I'd rather be slightly undersized

@ April 18, 2013 2:39 PM in Direct Pump TT Solo 110 with 3 zones

We plan on installing two 20,000 btu gas fireplace inserts at some point, so on design days we'd use them if needed, or sweaters. Third floor won't have installed radiation for a few years yet and will be used sparingly.

I'm mainly wondering about outcomes when all the below are promoted.

1.  Zoning, with some some zones having fairly small GPM requirements.
2. Avoiding over-pumping.
3. Large delta-t's, which I would assume regularly mean zones with very low flow requirements.
4. Direct-pumping.

Direct Pump TT Solo 110 with 3 zones

@ April 18, 2013 11:25 AM in Direct Pump TT Solo 110 with 3 zones

I have 3 zones with the following flow requirements:

Zone 1: 4.6 GPM at 30 degree delta-t.
Zone 2: 1.8 GPM at 30 degree delta-t.
zone 3: 1.0 GPM at 30 degree delta-t.

Oversized, cast iron radiators in all three zones.

I've been watching the ongoing discussions on circulators ....

If I were to direct pump the TT Solo 110, what circulators would you suggest I take a look at? My question primarily centers around maintaining the required flow through the heat exchanger. - there would be times each zone would be the only zone calling for heat.

We're where you are, kinda

@ March 17, 2013 1:06 PM in Retrofit/upgrade suggestions

We have an 1888 house in Minneapolis. Also rehabbing the windows. You'll tighten things up quite a bit rehabbing the windows. Our heating costs will be $4,000+ this year.

Running pex-al-pex off a manifold to your cast iron radiators will work with any future improvements. I ran pex with a manifold for first floor rads last Fall, and plan to do the same for second and third floor this year. I did a room-by-room heat loss and concluded I only needed 1/2 inch pex-al-pex. And we have some big rooms (16x16 with 10 ft ceilings).

We are undertaking weatherization retrofits like insulation and tightening the envelope this year, then ditching our boiler for a high efficiency unit.

If you are seriously going to consider replacing your boiler in the future, I would find a way to make that happen sooner than later. If you wait 5 years, all that money you spent on running that old boiler for those 5 years is gone up your chimney. It could have gone toward a new boiler, offsetting some of the costs.

I know there's only so much money to go around, and like us, you probably have many projects and you want to spread your money around a bit.

I concluded I could spend one dollar now, or spend that
same dollar down the road in higher heating costs - it's the same
dollar. We plan to be here beyond the payback period, but I also
consider it a home improvement if we were to sell ("new mechanicals!" as
the realtors like to say).

In Minneapolis, we are obligated to bring in an inspector when selling a house. They're tagging old boilers for inspections quite a bit and there is some liability for any company coming in to inspect the boiler. They have to fill out a form saying they inspected it, and it passed and submit it to the city.

If you plan on flipping the house and will only be there a few years, then have you considered a new cast iron boiler? Much, much cheaper.

Or maybe you could find someone to put in a cheaper mod-con (Munchkin?) and do the near-boiler piping, and leave you to connect your manifolds and run your pex.

Based on my own experience, I wouldn't spend any money on your current system unless those components would also be part of any future, optimally designed system.

replacing cast iron radiators with electric baseboard in a

@ February 28, 2013 10:35 AM in re-piping an old rad system...

Victorian house is like replacing double-hung windows with casement windows - doesn't look right.

If it's a true Victorian, with Victorian elements, such as millwork, flooring, large windows, the cast iron radiators are an important feature - a future buyer of that house may be turned off by electric baseboard. I know I would. Around here, the only older homes with electric baseboard are shoddy slumlord properties.

1/2 inch pex to cast iron radiators

@ February 28, 2013 9:06 AM in re-piping an old rad system...

I have a Victorian with large rooms - 16 x 16, 18 x 18, etc. I have the first floor piped with 1/2 inch pex to large cast iron radiators. It's more than adequate. I did a heat loss for each room.

I don't understand why you'd want to zone for each room. I plan on having two zones in a 4,500 sq ft house.

My goal is to balance the flow at the manifold to the targeted heat loss, once I have the entire system running.

For example, the kitchen has a heat loss of 18,000 btu's, so flow needs to be about 1.8 GPM with a delta-t of 20. Flow is about 1.2 GPM with a delta-t of 30.

I'm a homeowner, so the above are my calcs - could be wrong.

Thanks for the well thought feedback

@ January 26, 2013 10:03 AM in Large heating bills - where to go from here

You guys gave me much to think about. We've decided to first spend money insulating and addressing infiltration. Attic insulation; spray foam rim joist and other basement issues; insulating rooms scheduled for demo this year; rehabbing windows and replacing missing storm windows.

I'm going to replace the boiler this year as well. I may wait until December to do so. It will likely be a high efficiency boiler.

Edited post

@ January 22, 2013 1:15 PM in Large heating bills - where to go from here

icesailor, I updated the numbers - too many numbers to keep track of with kids underfoot.


@ January 22, 2013 11:42 AM in Large heating bills - where to go from here

Yes, we are at the coldest it's been in something like 4 years. It's -9 or -11 outside depending on your source.

The boiler operating temp is almost 170. The Grunfos pump is on high. The boiler is running constantly and not shutting down. I've monitored the boiler when temps are in the teens, 20's, 30's, and it short-cycles 2 minutes on, 2 minutes off all day long, so this is the first time I've seen it run like this. This must be because the Unico has been running a lot more.

We currently have 2 radiators shut off in rooms we are not using downstairs. These rooms are on the other side of the foyer, and a sectioned off with a vapor barrier. So we are heating with a radiator EDR of 70,000 and a Unico 3660 coil with 24 outlets and 800 CFM, and a water temp of 170. .The Unico specs say that produces about 65,000 to 70,000 btu's. This is assuming the flow through 3/4 pex is 6 gpm I believe. Maybe 3/4 pex can't do that and btu output of Unico is less. I need to get temp gauges and measure at the air handler to see what it's actual output is.

I have a Watts manifold with temp gauges and flow meters that supplies the radiators. The supply temp is 178. The return temp is 140. The flow rate for each line is about .5 to .75. So the total flow for those 7 radiators is about 4.5.

All that comes to about 85,000 btu's off the radiators and supply and return pex. I have about 290 feet of 1/2 inch P-AL-P pex down there. I found a Uponor spec that says 1/2 inch pex loses about 25 btu's per foot, which would put the heat loss at about 7,500 btu's.

The basement itself is only 38 degrees, so pretty cold.

House feels cold downstairs. It was about 69 at 9:00AM at the downstairs thermostat and 72 degrees at the upstairs thermostat. I have the upstairs thermostat set to 74 and the downstairs set to 73, so they're not getting satisfied, and haven't been in 24 hours. So am I safe to assume 140,000-150,000 btu's is holding these house temps in a very leaky house at -10 degrees overnight?

It feels cold downstairs for sure. But as you guys keep pointing that may be due to infiltration. I know we have a very leaky house.

window calcs/Triangle Tube 150s Challenger Solo

@ January 21, 2013 10:01 PM in Large heating bills - where to go from here

This assumes a design day of -15,  which is Minneapolis. That's what the software chose anyway. Internal temp of 72

Ti - To is 87.

Single pane has an r-value of 1. Double pane an r-value of 2. I have mostly single pane, pr storms missing their own panes. But for my own calcs, I assumed double pane, or storms.

87 x 764 = 66,468 (single pane)
87/2 x 764 = 33,234 (double pane)

If my heat loss will be in the range of 120,000 to 140,000 ( let's assume I make some reasonable improvements, such as attic insulation and some wall insulation) would the Triangle Tube 150s Challenger Solo be a good match?

If my heat loss were 120,000, would the Triangle Tube Prestige 110 Solo be too undersized? I read a post from someone on the wall who had a high efficiency boiler and the input was 10,000 btu's less than his house heat loss and he said it worked perfect.

Load calcs

@ January 21, 2013 1:33 PM in Large heating bills - where to go from here

Design temp in Minnesota, according the software, is -15. We may see that tonight, but this is a once in every 4 years. And we live in the city, so we have the heat sink.

Big factors in our load calcs are the poor insulation and the number of large windows.

We have 734 sq ft of glass. The windows on the first floor are all 82 inches tall and vary in width from 28 to 40 inches wide. There are four large bay windows on the house as well that are 48 inches wide

The heat loss for the windows totaled 35,760.

This was the Unico installers software - HVAC Learning Solutions. He had not done a load calc until things weren't working. He eventually sent it to me, and once I made corrections the heat loss went from 100,000 to 160,000.

Using the same software, when I add R13 wall insulation to 80% of the walls and R38 insulation for the attic, I bring the heat loss total down to 125,000.

The heat loss also is set for a loose house. If I uncheck loose, heat loss drops to 121,000.


@ January 21, 2013 12:01 PM in Large heating bills - where to go from here

I agree to an extent. No matter what solution is ultimately deployed, it won't feel warm if there's no insulation - in the attic, for example.

There are two things we're doing this year that will give us the best return. The attic currently has a mix of cellulose and sawdust. We are going to insulate the attic. We have a historical home, so instead of replacement windows, we rehab and weatherstrip and have well-made wood combo storms. Almost as efficient and proven so by the Department of Interior. 

As for the walls, there is a 19th century attempt at
insulation - a rough coat of plaster inside the stud cavities. There is
only 1 inch of air space inside the wall. We had part of the house jacked up last Fall. The rooms on that side will be fully gutted as the plaster did not hold - we'll take advantage of that and insulate. But some of the walls in the house (about 25 %) will not get insulation under our ownership, and we plan to be here 20 years.

Appreciate the feedback I've received; helps give me areas to research and possible solutions. This is what I needed.

Now it makes sense - thanks!

@ January 21, 2013 7:07 AM in Large heating bills - where to go from here

Eastman, thanks for your detailed explanation. I had the "lightbulb moment" regarding the open first floor. I've been thinking all along I want as many BTU's as possible downstairs because I will lose them to the second floor. What you're saying is there's a line where excess BTU's will actually make things worse and managing the first floor room-by-room btu requirements should be part of the solution.

It's clear an on/off solution is unworkable for this house and I'm going to have to spend some money to save some money.

We have ungodly amounts of infiltration, by the way. I had a blower door test last year and the guy struggled to even get readings off the front door.

Under-floor heat

@ January 20, 2013 1:44 PM in Large heating bills - where to go from here

Thanks for suggestions. I have some things to think about. I have the Siegenthaler book, but haven't read it cover-to-cover.

Would underfloor heat be worth considering to keep the floor warm, but not necessarily shoulder heating the house? With the controls out there, could we use underfloor heat as a first stage, then the cast iron radiators as a second stage, including the necessary mixing of different temps?

Right now, leaning toward not using the Unico to heat and instead add four radiators (one for each bedroom) upstairs - about 40,000 BTU's. That would total 140,000 BTU's of cast iron radiators for the first and second floor. I would think as we tightened, they would end up oversized, which would enable us to run lower temps.

One reason for not relying on the downstairs radiators to heat second floor bedrooms is the rooms themselves get chilly. We have 3 kids under 4 and doors are always closed for nap time and overnight.

I could probably achieve room-by-room efficiency upstairs with TRV's.  Downstairs is so wide open, I'm not sure zoning for individual rooms would get anywhere. The opening between the dining room and living room is 12 ft. wide. The four openings into the foyer are each 6 ft.

Would one modulating boiler work efficiently under this scenario? (under-floor heat and radiators on first and second floor)

Total EDR Originally in the house

@ January 19, 2013 12:25 PM in Large heating bills - where to go from here

We live in Minneapolis.

Everyone says things were oversized in the day and it makes sense, as I can heat the first and second floor just with the 98,000 BTU in radiators on the first floor and the Unico System off, when temps are in the 20 degree range. It feels cool upstairs but temps stay at 68 degrees.

Originally, there was a total of about 180,000 EDR in cast iron radiators for all three floors. About 95,000 on the first floor, 42,000 on the second floor, and 45,000 on the third floor.

We do not live on the third floor at all. It's just used for storage. Eventually, we will use the third floor for home office and family room and guest room. For now, I chose not to heat it. I understand that the joists are not insulated and there will be some heat loss to the third floor ....

As for underfloor heat ... another option I thought about is just dropping a few radiators in the basement to keep the chill off the first floor floors. The floors definitely feel cold underfoot when we have temps in the single digits. You notice it. When family visit there's some whining about feeling cold. There's mortar packed in the rim joist pockets and I plan to knock that out and spray foam.

Would two boilers be the right option with 3 zones, 1 zone per floor? Something that would be modular, in that I could add to an existing system once we were ready to make the third floor livable space.

Talked to Unico

@ January 19, 2013 8:48 AM in Large heating bills - where to go from here

The Unico is not zoned. They put in one zone for the whole house. There are two returns: One one the second floor, at the top of the wall where it meets the ceiling, right above the stair landing. The other is on the first floor in the dining room, near the floor.

I talked to Unico a few times. They thought 1 inch pex supplies should have been used, and there should have been two air handlers and hot water coils, one for each floor. They did not think one hot water coil could heat the house.

I think our installer had a lot of experience putting in Unico A/C retrofits, and thought they can just plug in the heating module. Unico has worksheets you can fill out to guide your design.  For example, our installer put in two outlets in our foyer. It's 32 ft. by 16 ft, with 10 ft ceilings. Following Unico guidelines, that foyer should have had at least 6 outlets. All the rooms downstairs should've had more than two outlets per room. They also did not study the Unico Heating Module Specification 3660. It has a chart that shows 24 outlets gets you 800 CFM and a max of 86,000 BTU's, if you have a flow rate of 10 GPM. That's a theoretical max, and Unico says don't expect that. Unico says my install likely produces around 70,000 BTU's, evenly distributed between the first and second floors. Last Winter, we had temps downstairs in 40's. We ended up putting .6 mil vapor barrier over those foyer pocket door openings to retain the BTU's in the living room and dining room. We still had to stay in a hotel during some cold spells.

I would rather add radiators to the second floor and abandon the Unico heating module altogether than add a bunch more outlets and another Unico air handler and heating module. The central air works nice, so it's not a total waste. I would like to re-run the ductwork and just have the Unico on the second floor for now, and eventually the third floor. I have the Advanced Control Board, so I can tamp down the CFM to match fewer outlets. The neighbors across the street have a Unico A/C and the installers just put outlets on the second and third floor - no outlets on the first floor.

I am not familiar with using a designer. I've had 5 different HVAC guys out - hydronics guys, Unico guys. Nobody seems to know enough about Unico AND hot water radiators AND the challenges that come with these big old homes.

How I got a 210,000 BTU boiler for a 70,000 BTU Unico

@ January 18, 2013 10:36 PM in Large heating bills - where to go from here

We bought the house with freeze damage, so all the radiators and boiler had burst/cracked. We received a bid for a Unico System AC and heat. This was installed in two phases in 2011. Well, we discovered the Unico System could not heat the house last Winter. The contractor dragged his feet for weeks, we stayed in a hotel one weekend as it was too cold in the house. We also had plastic vapor barriers up to keep heat in one part of the downstairs.

I started reading and realized the contractor made a mistake. As installed, the hot water coil would only produce 70,000 BTU's. This is due to the 3/4 inch pex supply, and also the number of outlets. The maximum amount of BTU's the hot water coil can produce is a theoretical 110,000. You need about a billion outlets, 1 inch pex and and it sounds like a jet plane. I was a newbie to HVAC, unfortunately, and did not know how to salvage what was there. After much back and forth, we agreed there was not enough BTU's in the Unico System to heat the house. He agreed to put in a larger boiler and I then added the radiators myself this fall.

That brings me to this Winter. We now have heat, but huge bills. And I know the boiler is short cycling.

I used a temp of 170 for the radiator EDR.

Could underfloor heat run off the same zone as the radiators?

I'm talking to someone who might sell me their Triangle Tube Prestige Solo PS110 to replace the Slant Fin 210,000 boiler. I was then thinking I could get a small boiler for the Unico and just run the Unico ductwork for the second floor for now. The Unico does nothing for the first floor, except make it feel more drafty.

Heat loss

@ January 18, 2013 4:36 PM in Large heating bills - where to go from here

We use natural gas. I will be doing all the work myself going forward.

I have load calculations. All 4,500 sql ft of finished living space has a heat loss of 161,636. I also have radiator EDR, which is 98,000 BTU for the first floor.

Unico hot water coil can put out 70,000 BTU max as it's installed, distributed between the
first and second floor. I adjusted the CFM and have it running at 50% of capacity or about 35,000 BTU's. There are no radiators on the
second floor. The Unico System calls for heat infrequently.

I'm rehabbing the house, so things will tighten up as I move along. Currently, there are no storm windows and all the windows need to be rehabbed and weatherstripping added. Lot's of air infiltration that I will be addressing. I will be adding R40 insulation to the attic. Some of the rooms will require gutting and will get insulation where currently there is none.

Because of the layout of the house, the radiators on the first floor are not just heating the first floor. I wish that were the case. We have a 32 ft long x 16 ft wide foyer with a staircase that's 8 feet wide in the middle of the foyer. So the opening over the stairs between the first and second floors is about 8 ft x 8 ft. All the rooms on the first floor are open to the foyer.

98,000 BTU of cast iron radiators on the first floor is plenty. I figure I need only another 55,000 BTUs total for the second and third floors - 25,000 for the second and 20,000 for the third.

Right now though, I'd say 80% of the time, the first floor radiators are calling for heat only. The thermostat on the second floor only occasionally calls for heat. So we have this 210,000 BTU boiler firing for at most 98,000 BTU's of cast iron radiators. The boiler runs for 2-3 minutes and shuts off for 2 minutes, then runs for 2-3 minutes.

I attached a picture of the foyer.

Large heating bills - where to go from here

@ January 18, 2013 1:53 PM in Large heating bills - where to go from here

We had a $600.00 heating bill for the month of December.  I'm looking at making some changes.

Currently this is the set up:

Slant Fin Sentry 210,000/176,000 gas boiler. 98,000 BTU's of cast iron radiators on the first
floor. 3/4 inch pex to a Watts manifold and 1/2 inch pex to the radiators.

A Unico System hot water coil with 25 outlets on the first and second floor. Installed capacity
is 70,000 BTU's. 3/4 inch pex supplies the hot water coil.

There are two zones, one pump. A thermostat on the first floor is dedicated to the cast iron radiators.
A thermostat on the second floor is dedicated to the Unico System.

The house is a 4,500 sq ft. 3-story Victorian built in 1888. The finished 3rd floor is not heated. There
are 10 foot tall ceilings and a large, central foyer with a large, open staircase.

I was thinking about ditching the 210,000 boiler and getting two, high efficiency boilers - one dedicated
to the first floor cast iron radiators with an outdoor reset and one dedicated to the Unico System.  The current boiler short-cycles like crazy.

I was also considering under-floor heat to provide some warmth underfoot, though not necessarily shouldering a
significant amount of BTU's.

We had the Unico System installed last year as we bought the house with freeze damage. I knew nothing about HVAC
at that time. It was undersized for the house, so I added the radiators myself this Fall. I'd like to salvage
the Unico System and dedicate it to the second and third floor.

Is this a good approach or should I consider something else?

It pressure test ok at 30 PSI

@ October 31, 2012 5:11 PM in interior rust and chunks in hot water radiator

I'm in the process of adding around 85,000 BTU's of radiators to the first floor. This will run on a separate zone with a first floor thermostat. I have three hooked up and running so far, but was concerned about this one. It looks to me like there are chunks just sitting on the bottom.

Not sure what I posted toward the end last Winter. The contractor eventually replaced the 110,000 BTU boiler with a 170,000 BTU boiler.

There is one circulating pump and two zone valves. The circulating pump was installed on the return side. I don't know if there should be two separate pumps.

I will try and strike some sort of balance between the design goals of the Unico hot water coil and those of the radiators. Trial and error and come here with questions ...

interior rust and chunks in hot water radiator

@ October 31, 2012 8:14 AM in interior rust and chunks in hot water radiator

One of the radiators I bought from a salvage place has flakes of rusted bits anywhere from the size of a dime to a little larger than a quarter inside. I haven't hooked it up yet.

I'm wondering if that would be considered normal, or should be a sign the radiator is nearing the end of it's life.
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