NH radiator retrofit, control strategy

H2OBandit603

I am having the entirety of my parents heating system replaced.  Original Weil McLain boiler from 1984 and 4 zone baseboard is being removed. Domestic hot water is already handled by a new SanCo2 split heat pump outside with 119 gallon tank inside so the new boiler will not see any domestic hot water demand.

An Energy Kinetics Resolute RT oil boiler and Runtal radiators are being installed throughout with a new manifold distribution system with two HePex pipes to each radiator.  House is approximately 2000 square feet with finished walk out basement. 10(11 if the master bath gets it’s own) rooms needing individual control, 15 radiators need to be installed and the energy manager on the energy kinetics can be expanded to 15 zones so naturally I’m thinking this is a shoe in for each radiator to be it’s own zone allowing them to be grouped by room into synthetic zones and achieving individual room control.  Leaning towards Ecobee smart thermostat premium.

My question is:  What are my options for control strategy.  I assume you would put a thermostat in every room needing control and I’m willing to spend the money to make that happen but what other control strategies are available?

If I do a thermostat in each room do I pony up for 11 ecobee smart premium or get one or two of those and a cheaper/lower end ecobee thermostat for the less prominent locations?

the reason my initial instinct is multiple thermostats is a design requirement is total smart phone control of all rooms.

Thanks in advance for any input.  Still in the design stages and meeting with the installer at the end of the month for a final design session.  

kcopp

No pricing please.. It is in the rules. Thanks

Jamie Hall

Is there a reason to not use TRVs?

mattmia2

If you're doing a t-stat per room, does tekmar or honeywell have a system that can have sensors or sensors with control in each room and a central controller that sets schedules and can be controlled over the network?

you'll probably need a buffer tank to handle when one or only a few zones are calling if the zones are that small.

hot_rod

Runtal panel radiators or baseboard?

on panel radiators a TRV on each one would be ideal

one central Ecobee as a start up snd high limit control

TRVs give you non electric, proportional control. One single delta p circulator.

Your home run idea works also

If you have multiple rads in one room you would series them with a single TRV  That would cut down on the individual controls

Hot_water_fan

Room by room control is done with thermostats or TRVs. But is it really necessary? People aren’t really thermostats, will they notice slight temperature differences ?

H2OBandit603

This is one of those situations where I want to do it right the first time.  There’s no way I could justify future upgrades and room by room control as well as app based control are both desirable…

most of the time it’s just the two of them in the house and being able to dial in their comfort in a particular room when alone and when they have family seems ideal.  Do you think the energy kinetics resolute RT really needs a buffer tank?

Proposed Runtals

1st Floor

Living Room/Kitchen: (2) UHX-8 72”, (2) UF-4 10’ Entry Foyer: (1) UHX-4 72”

Bed #1: (1) UF-2 6’

Bed #2: (1) UF-2 8’

Master Bed: (1) UF-8 4’

Master Bath: (1) UF-6 3’

Basement

Office: (1) UF-3 11’

Bed #1: (1) UF-2 8’

Bed #2: (1) UF-2 6’
Living/Workout: (1) UF-2 12’
Bath/Laundry: (1) UF-3 6’
Garage: (1) UF-6 3’

Roger

Thank you for your questions and details, @H2OBandit603 , and for everyone's thoughtful responses.
We would recommend that you zone by comfort areas (master bedroom/master bath, maybe bedroom 1 and 2, living areas like living room and kitchen and maybe some others nearby), maybe 3 or 4 zones total. You listed zones, but I'm not sure how they relate as contiguous comfort areas. If you zone all 15 spaces, in addition to costing more and being more complex and difficult to service, something will often be calling and the boiler will frequently remain hot, which is a primary way to run inefficiently.
Zoning "comfort areas" will allow rapid heat up and thermal purge, which is great for comfort and efficiency.
If you are really set on a high number of small zones, then a buffer tank served by the boiler would work; then a separate controller to feed a primary/secondary loop from the buffer tank, with independent thermostats/zone valves/circs and/or TRVs for all of the zones depending on the ultimate design.
Best,
Roger

Hot_water_fan

Proposed Runtals

1st Floor

Living Room/Kitchen: (2) UHX-8 72”, (2) UF-4 10’ Entry Foyer: (1) UHX-4 72”

Bed #1: (1) UF-2 6’
Bed #2: (1) UF-2 8’
Master Bed: (1) UF-8 4’
Master Bath: (1) UF-6 3’

Basement
Office: (1) UF-3 11’
Bed #1: (1) UF-2 8’
Bed #2: (1) UF-2 6’
Living/Workout: (1) UF-2 12’
Bath/Laundry: (1) UF-3 6’
Garage: (1) UF-6 3’

Have you determined a heat loss? Is the goal to run low water temperatures? You have a TON of radiation, which means you can use lukewarm water. Right now, I ballpark this at about 90,000 btu of radiation using 180 degree water, about 34,000 at 120 degree water. Lower water temperatures open up lots of possibilities, but of course this much radiation is expensive.

hot_rod

That design is what could be considered a micro zoned system. As such it will caused any fixed output boiler to short cycle

Group some rooms as Roger suggested, or add a buffer tank to extend the off cycles of the boiler 

If you do a home run you could combine zones or have each zone by itself just by how you wire the actuators

With a buffer, the boiler sees the buffer as the load, the rads sip from the buffer

properly piped the buffer us a primary loop

Alan (California Radiant) Forbes

I've always figured zoning by:
- Area usage: living areas vs. sleeping areas vs. work areas vs. guest areas
- Room exposure: east facing rooms will get morning sun and visa versa
- Floor surfaces: tile floors will heat rooms faster than carpeted rooms, especially with wool carpets
- Civil warring: Give each child their own thermostat.

But don't go overboard; keep it simple and straightforward. And don't overthink it. All my "zone each room" customers are not happy with their choice.

H2OBandit603

I havnt seen the manual J short form yet but he did take measurements and run the calculations.  Final design session on the 28th.  I’m definitely seeing the benefit of four zones with TRVs for room control now.

Hot_water_fan

How much oil did the old boiler consume per year? 

H2OBandit603

1200 gallons with the domestic hot water on a 50 gallon top performer indirect tank.  Another 200 gallons of propane but that’s the range, grill, dryer and a space heater in a small second garage that was added on not part of the original house.  The original boiler was not a cold start and stayed hot all summer just for the DHW and it’s in rough shape since it was installed in 1985 and can’t be operating at anything approaching it’s design efficiency which I gather wasn’t very high to begin with.

H2OBandit603

I appreciate all the comments so far and now I am questioning whether or not I want a buffer tank. 

4 zones, 15 radiators, Space is at a premium but there’s room for a 40 gallon tank.  In a perfect world would this system have a buffer tank?  Longer run times seem an obvious benefit.  If I do a buffer tank does it now make sense to run an outdoor reset and run the radiators at lower water temp?

let me know if I’ve already home owner over engineered this.

Roger

For your application, the most efficient application is zoning comfort areas with proper piping and circulation to ensure even heat in each zone. The boiler will then be able to effectively thermally purge and deliver high efficiency.

H2OBandit603

I feel pretty confident now.  This forum is a great resource, having knowledgeable people who are willing to take a little time out of their day to contribute makes a world of difference, even if in hindsight most of the questions were pretty stupid. 🫣