Apartment building zoning solution - Tekmar tn2?

tivo

It's regarding zoning my house, a multi-family building in Boston.



There are 5 stories and We live on the bottom 2 floors so technically there are 4 units. There're baseboards throughout the building, so, one temperature, one zone, powered by a viessmann boiler, vitodens 200. In addition , I have an indirect tank, on priority. There is no separate control system other than the one builtin in the boiler.



My goal is to be able to control the temperature on each floor with sensors and zone valves on each floor. My initial plan is to get the tn2 house control 400, 4x indoor sensors, 4x 518 thermostats, 4x zone valves. My first question is, am I on the right direction? Also, the 400 offers some redundant features, such as outdoor reset, since my boiler is already doing the modulating. My second question is how do they coexist or whether I can disable the modulating in my boiler and let the 400 do it all?



Any advice will be greatly appreciated.



Thank you in advance!



Rob

heatpro02920

I personally

would not go with zone valves, I would give each floor its own Bumble bee circ. set up for delta t, I would also just run a taco sr504 {or how ever zones you want}, let the boiler do what it is made to do as far as reset and DHW priority, just use the zone board and sensors for zoning, it will cost much less.



You need to figure out your current piping configuration and where to split it, probably much more important than how you control the zoning is the piping...

If its possible to make a fast drawing of how its currently piped that would be helpful..

tivo

I love bumble bee and the delta t feature too but...

The challenge I have is that only the supply and return pipes near the boiler are accessible. The splits of the pipes are all hidden behind walls. As far as I know, there is no easy way in my situation to install separate pump and that's why I'm considering zone valves on each floor instead. The wiring of the zone valves can be another challenge but let's set that aside for now. I'd like to first find out whether my initial plan is feasible.



I'd love to have a drawing of the piping configuration too. I actually considered buying a flir camera and spend a day or so going through each apartment but shelling out a fortune for the camera for a one time project really keeps me for doing it. Is there a better way to map out the piping behind walls?

heatpro02920

OK,

so you want to install a zone valve in each unit, I have done it this way before... BUT you really need to know where the pipes are coming from and where the tees are.... I offer thermal imaging services, but it may be cheaper to buy a camera, since it can get time consuming....



Having a drawn out piping print will save you when the contractor comes to install the zoning since he is going to charge you to figure it out himself...



The thing with the tn2 is you dont need 80% of the features, so to buy a $450 control when the $150 taco control will do what you need is kind of a waste..



If you are going to use zone valves I would use a grundfoss alpha pump, taco sentry valves, and the taco zvc404 control...



Problem is with out know how your building is piped you have no idea how to zone it, I have seen multi levels that feed all the floors on different walls, in other words the pipe on the north wall is feeding all 5 floors, so you can only zone the base board on them walls together...



Do you have some pics of the piping you can see, another option depending how its piped is to install thermostatic valves {trv}at each unit... If I knew how it was ran I could give you some ideas..

tivo

Taco zvc + sentry valve it is

Thanks for pointing out a better alternative using taco zvc and sentry valves.

What thermostat/sensor combo would you recommend? I'd really like to keep my tenants from messing with the thermostat so a TT/sensor combo would be better. Currently, there is only 1 TT for the entire building and the temp varies greatly especially the top floor where heat loss is the highest and I get complaints every year, which is actually the main reason why I'm considering zoning.



Also, does taco sentry zone valve fit inside the baseboard?

heatpro02920

You can do a t-stat with

a lockout code or a simple construction sensor like the icm sc070 or what ever temp you want to fix them at...



I made a little configuration up for a customer of mine, it is a 65 degree pill and a 70 degree pill with a stdp switch mounted in a box with a cover marked high low off, they flip the switch to high and it goes to 70 low goes to 65 and off shuts the tstat off... He installs them in all of his apartments...

icesailor

Zones: (Back To Basics)

That's a lot of ca$h you're thinking of spending and it still won't solve the problem.

Which all started when the person that replaced the boiler and must have re-piped it, didn't do a comprehensive and accurate heat loss on the building. Plus, a comprehensive installed radiation comparison. That would have shown that the top floor (as usual) in the building was under radiated. So no matter how much money you spend on zoning, the system temperature setting will require that the water temperature in the system be enough to heat the top floor. Regardless of the requirements of the rest of the building. This building must have had a serious gut re-hab and eliminated the old gravity or steam system. If it was gravity, the top floor probably worked fine. Until someone ripped out the radiators and piping, and undersized the distribution system. Especially when they got to the top floor.

Take that Slant-Fin Heat Loss Explorer (free) and do a comprehensive heat loss on the building. Especially the third floor. But you MUST use the same factors for each and every room and floor. If there's a ceiling skylight like some old buildings in Boston had, be generous with the heat loss. Then, measure the installed radiation and compare what is installed in each room and each floor. You will see patterns. One pattern will be that the top floor is grossly under-radiated. As a rule of thumb, I always figured Slant-Fin because that was what was easily available to me. If it is #30, I figured 600BTU's per foot at 180 degrees. #15 at 550 BTU's and #80 High Output at 740 BTU's. So, every 10' of #80 you replace is equal to more than 2' of active baseboard. Its just a rule of thumb for guesstimation purposes. But if you don't solve the direct problem on the top floor, you will only be putting a Band-Aid on an infection. Someone should have put some Bacitracin on the wound.

My Grandmother had one of those buildings on Pinckney Street. A big pumped gravity system. The top floor worked as well as the basement and garden apartments. Someone abused the pooch. Make amends to the pooch and everyone will be happy. Then, you can decide if you want to spend massive amounts of ca$h trying to improve something that (now) not broken.

Plus, that Vitodens 200 will whisper sweet nothings in your ear. You're not using the ODR and you want to replace it with something else?

IMO.

SWEI

Once you veirfy the radiation is right

as Icesailor pointed out, you really should consider TRVs, perhaps the ones with remote bulbs.  Outdoor reset does not play nice with on/off zone valves.



I would do this using DDC and proportional zone valves, but that's not an off-the-shelf solution.

icesailor

Corect circulation

TRV's don't work well with series looped baseboards. Zone valves work fine with variable speed pumps. I'll bet this building has one big over designed or under designed pumps as part of the problem. If there isn't an accurate pressure gauge on the supply and return, I'll bet the pump is pumping too high or not enough water.

An El Cheapo Infra-Red thermometer gun might show wonders on where between the floors, the system became unbalanced. Like the return water is warmer going back to the boiler than it is going in to the top floor supply. A variable speed pressure actuated circulator could be a beautiful thing in that application. Temperature, NO. (IMO). If the return gets hotter than an upper zone, the upper zone will get colder as the circulator closes down. The longer the circulator runs at a low temperature or closer to the needed water temperature, the more the system acts like a properly designed gravity system.

Get the correct temperature water and radiation and it will be a perfect system.

SWEI

Series-looped baseboard

is the work of the Devil in my book.  But that's just me.

heatpro02920

Series loop

It has its place, its cheap, its fast, and although should get a lot of thought in its design doesn't...

SWEI

Understand completely

If the loops are short and the sizing is done right and it's run on ODR it actually works pretty well.  I have reworked more than a few over the years -- we usually and up splitting the loop (usually 2 or 3, but sometimes into as many as 4 or 5 sections.)  For new construction, PEX with a proper reverse return costs less than a copper loop does.

heatpro02920

Yup when done rite it can work well

but then your loops end up being so tight you can run into short cycle issues with cold start

icesailor

Work of the devil:

It's the work of the Devil, only of El Diablo does a bad job on installing it.

I'd rather be installing 80' of series looped baseboard than stand by and watch 80' of electric heat baseboard go in. Or a bunch of metal grills in the floor, connected with 8" R-6 round flex duct in a cold crawl space.

icesailor

Methods:

On renovations and electric heat conversions, I always went wall to wall and through the wall, with the supply and return on one end with the supply or return going over the top of the element. My drills would go anywhere and drill through anything. Nails, bolts, knots, wires, it didn't matter. Drill baby, drill.