Need advice regarding adding buffer tank and replacing mixing valves

Forgot to mention I do have ODR tied to the boiler. The boiler does have spare capacity. It is a W/M ultra 230 . Only adding about 6 or 7 thousand btu's to the load due to the removal of a vary large ceiling radiator in the garage. I think the rad is about 13 thousand btu's.

Large boiler is due to a 4300 square feet Tudor three story home that was built in 1928. The construction of the exterior walls are brick with clay tile. Plaster over the clay tile on the interior. House has 36 windows, some quite large. I have insulated the heck out of the house with new windows & doors, studded out some exterior walls on the inside where I could such as the kitchen, den, living room and 2 bedrooms. Installed more insulation in the three attics and knee walls. Much of the piping to the cast iron rads are on the exterior walls that run to the second and third floors through exterior wall chases in the brick and clay tile and are uninsulated. The renovation including boiler and in floor heat was done during the 2008/2009 renovation of the complete house

The W/M boiler was installed in the fall of 2004 so it does not have the updated tech of the newer models. The heating design in 2004 included all the new windows, doors, new insulation, on slab gypcrete pours and installation of the radiant heated floors in kitchen and baths when calculating the proper size of the boiler.

I have four zones working at present and the boiler high fire has been set to 165 degrees. Zone 5 (garage) is not tied in to the boiler as yet until a decision is made un upgrading the mixing valves and installing a buffer tank. The work will be held off until the heating season ends.

Zone 1: Fifteen cast iron rads and two in wall fin tubes, first floor: 6 rads and one in wall fin tube; second floor: 6 rads and one in wall fin tube; 3rd floor: three rads

Zone 2: Bar/Pool/Family room was an addition constructed in the 1950's on the east side of the house. At that time former owner incorporated a 3 sided porch into this Bar/Family room addition by removing one side of the brick arches from the porch and makes the room 36 feet long on a concrete slab. Above this porch is the original master bath room. Porch had brick walls that had two large arches per side that were enclosed using studs and windows. New windows in the 04/05 reno now fill these arches on two sides This space before the 04/05 renovation had its own gas forced air furnace which I removed and did a gypcrete pour over with pex. Also included in this zone is a rear enclosed porch/conservatory also used gypcrete pour over on the rear porch slab. Both spaces are on one thermostat that is located in the Bar/Pool/Family Room. The Porch/Conservatory only needs enough heat to keep it in the 50 degree range in cold weather. Cost to pull up the old slabs and insulate was just to many dollars. This zone runs the most. I do realize these two spaces are probably the costliest to heat. I know, I have a nice snowmelt system on the exterior perimeter of this space. Both spaces have tile floors over the gypcrete

Zone 3: Three bathrooms; master, and two guest baths on second floor. The thermostat is in the master that controls all three baths. This is the smallest zone and has a tendency to short cycle. All baths are a a gypcrete pour over joists and well insulated below the floor. All floors are covered in tile or stone.

Zone 4: Kitchen & dinette, gypcrete pour over joists well insulated below floor. Stone covering gypcrete.

Future zone 5: Garage floor, removed old concrete, two inch foamboard, pex installed per professional design with heat loss calculation for number of loops. New concrete pour. Not yet tied to the boiler. Am removing a massive radiator from the garage ceiling that is about 13,000 btu's. If I remember correctly the radiant heated floor load will be about 16 or 17 thousand btu's. The boiler has that extra capacity.

Zones 3 and 4 seem to run off and on a great deal more so than the cast iron rads do. My thoughts are that an appropriate sized buffer tank and improved higher tech mixing valves (manual ones now and not sure if set properly) plus using my current ODR with the buffer tank will give me improved energy efficiency and help to prolong the life of the boiler. Utilizing the buffer tank should help to stop the on off cycle such as zone 2 fires and then is off and a few minutes later another zone fires and then goes off. Shouldn't the zones drawing off a buffer tank help to slow the number of times the boiler fires on and off in a twenty four four period? Seems the colder the weather the more the zones are on off within a few minutes of each other. I think colder weather makes some of the smaller zones short cycle much more often. Can't remember maybe it is the large zones on slab that short cycle in really cold weather.

Also included in the proposal I have is a Ranco ETC Commercial Temperature Control. Not exactly sure how this piece of equipment will be utilized.

Any other design ideas are greatly appreciated. Hope my description above can give some what of an idea of the layout.

Thanks

Scott

After looking at my records I had to go back to revise the age of the boiler and the renovation project which was also done during the 2004/2005 period. Boiler was installed in Oct of 2004 so guessing the boiler does not have any ability to adjust it in any way and does not have a way of checking boiler cycle averages due to the age. later models were built with more sophisticated technology.

Hot Rod my writing of the last post may have not been as clear as it could have been. Do have short cycling. Checked on the boiler tonight and found boiler doing several on off on off during a zone call for heat while the pump continued to run until the thermostat was satisfied. Buffer tank should stop this from happening???

I do have manual mixing valves on the radiant heat zones. I am not sure they are set properly. I have read some posts on The Wall from what I can tell are from some of the more knowledgeable posters that pex should not have more than 110 degree water through it. That is how I set the manual mixing valves. Would that be correct? Is there some other formula for setting mixing valves.

What is the abbreviation SWT ? I may have known this but have since forgotten

Shouldn't a buffer tank also help with less boiler cycles when a couple of zones go off and on within short intervals (minutes) of each other ???? With a buffer tank I thought a zone or zones would draw hot water from the tank and the boiler would not fire until enough hot water would be withdrawn and the temp of the tank would go below a set point. I assume the boiler should not fire the instant a zone comes on and starts to pump hot water out of the tank?

A bit frustrating for me not having a better understanding of hydronic design......wish I knew more. Reading The Wall has been very helpful over the years.

Hot Water Fan, my lowest consumption of gas was 1500 ccf for the calendar year Jan. thru Dec. of 2012.
I think that was a warm winter for near Pittsburgh, Pa. My highest consumption was calendar year 2019 which was 1904 CCF's. My records are for a 16 year period from 2005 through 2021. In dollars of course the lowest cost was 2012 and the highest cost
was 2021 even though consumption was less than 2019. Have attached a photo of the pile of bricks.

I looked at the paperwork on the boiler and it is a series 2 and is piped primary secondary Watched the on off today and boiler shuts down 3 or 4 times during a call for heat when boiler water reaches 165 degrees. Shut down lasts about 2 to three minutes. Then fires up again. Will get picture of the piping tonight.

Hot Water Fan, I am kind of a bit anal when it comes to tracking gas and electric usage. It can be a way to tell if something is terribly wrong. At least I can use the data to see if there is some kind of trend. Have some of the prior owners usage and the winter bills were huge when the cast iron boiler was in use.

The firm that installed the boiler, radiant floors and piping mentioned today about reviewing the heat loss calculation they did back in 2004 if and when I need a new boiler. The guy who designed the system in 2004 said the 150K W/M boiler was to small for the load and and the next size up was the ultra 230.

I try to keep the thermostat in the high sixties during winter....Think a cooler house is healthier. Thanks for the nice compliment on the house.