Flow direction baseboard ?

[Brian V]

Hey all,

Got a somewhat stupid (atleast I'm kicking myself in the ass for not knowing 100%) question about which direction a hydronic loop should flow and thermostat location in relation to the flow. My background was primarily comercial hvac/r and didn't do much with residential hydronic systems. Got out of the trade about 5 years ago to go into networking and have been here since. Anyways...I'm in the middle of replacing my single pipe steam system with a baseboard system. Entire old system is gone including boiler. Ran a manual J (wrightsoft) and also ran a load calc with Slantfins Hydronic Explorer, nice to see 2 different apps come out to within a 100 btu's of eachother. Sizing is no question, all set there. My question which I'm trying to verify again is direction of flow.....2 zone and a domestic loop with priority... Zone 1.... 2 bedrooms and bath, 50% exposed wall, bdrm1 north/east facing, bdrm2 south/east facing, bath south. Zone 2.... living room, kitchen and sunroom, again 50% exposed wall, living room north/west facing, kitchen south/west, porch got 3 exposures, north/west/south

Do I want the flow to hit the coldest area's first (Zone1 bdrm1, Zone2 living room) or do I want to revese that due to the tstats being in those rooms. I believe that the tstats are to be located at the end of the loop, atleast thats what I remember, which tells me end of loops in bdrm1 and living. Damn I hate being out of touch......

Thanks all.

-Brian

[kenny b]

Sounds like your building a watch! I use to try to be perfect all the time too, but then I kinda grew up fast when it started to effect the pocket book. Do you really think its going to make a rats ass of difference here in what you discribed if the heat loss and unit size is correct. For christ's sake its a small 2 bedroom house, no? As far as the stat location lets see: zone1- bathroom?- no, lets take a wild guess and say the primary bedroom of the two. zone2- kitchen?-no, sun room- you've got to be kidding right- guess that leaves the living room huh! A little common sense goes a long way.

kenny b

[Lori & Dean Wigmore]

Out of curiosity, what are you going to control the zones with (zone valves, automatic valves, circ pumps)? Also, will your boiler be on (circulating and keeping water hot) all the time? You might want to check out

for system design ideas. To answer your original question, though, the control generally goes at the downstream end of the zone.

[Brian V]

Thanks Dean, thats what I thought. Zones are going to be controled by circ pumps (007's). Boiler will be cold, switched when either a zone calls or the domestic, at least thats what the plan is, I'd prefer not to cycle off the limit control. I used to deal with Tekmar a lot, they make some real decent controls, very reasonably priced too as I recall.

-Brian

[Lori & Dean Wigmore]

Sounds good, Brian. I would strongly recommend a controller such as Tekmar when zoning with pumps. Be sure you read the installation instructions, and understand the piping layout, as "ghost" flow is more of a problem as there is not a positive shut off. You may want to consider using the new Grundfos circ that has an integral check valve. It's also 3 speed, so you can slow it down. I have found that, when done properly, zoning with circs is extremely effective.

Dean