Primary / Secondary Manifold?

Nick_11

See attachments. Anybody have thoughts about using a hydrolic seperator-manifold like Caleffi's Hydrolink? It looks like it could implement a primary circuit w/4 seperate secondary circuits in a nice small area.

They say it "can be fitted to any kind of hydrolic circuit."

I'd like to use it in combination with 4 UP15-58 circulators controlling the four secondary circuits.


Any alternatives, ideas and input appreciated.

Thanks!

Nick

DaveGateway

hydrolink

Nick,
I saw this in www.pmmag.com Bill Patrick

hr

Why P/S?

if this is a one temperature base board system, why do you need, or want, to use primary secondary?

And with zones that small one pump with zone valves would work fine.

Seems even on speed one you have a lot more pump then you need, on those small zones.

hot rod

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Nick_11

Rules of Thumb?

Hi Hot Rod,

Thanks for your response and questioning of P/S! Tell me what you think of the following:

I set it up as P/S system based on:

Overall issues.
Cold Climate. Mpls/Stp we can expect 3 to 7 days -15 to -25 every 2-3 winters. Extreme cold could be -30 to -35 for 1-2 days once every 10 to 15 years. We Average 0 to -10 about 10 days every yr. (my own guestimates)

Apartment issues: Old structure. Will never insulate like newer bldg.

Existing baseboard is 3/4" copper.
I need seperate zones for garage and indirect DWH.

I used following Rules of thumb I got from this site (heating Q&A) and from a Bell and Gossett zoning article (see BellGossett.pdf attached).

1. 67' per loop Max for 3/4" baseboard at 20 deg temp drop
2. 4' of head for every 100' of pipe.
3. 4 gpm max flow rate per loop.

So the total system contained 160' fintube, 570' total pipe. This calculation gave me about 23'. Both more than the rules of thumb above.

So I figured I had to break down my 160' of fintube (diagram on original post) to about 67' max which gave me 4 loops (53, 45, 32, 30). Head on each loop would be between 4 and 7 ft.(7', 7', 6', 4').

Then I took the 4gpm max flow and head req. for each loop and matched them to the grundfos operating curves and came up with the UPS15-58 FRC. If I fine-tune calculations for flow check valves, etc. The total ft of pipe in each loop will increase.

Though initial cost is higher by $405. each pump is about $95 and each flange set about $45 compared to larger pump of about $250; need pump for DWH in either case. I can keep a spare pump for $95, or swap one If I have a problem on SuperBowl Sunday when its -21 deg. My $405 difference could be eaten up pretty fast with service / repair on the larger pump.

Again, I'm glad for your counter point. If the 67' rule of thumb isn't really necessary, There is no sense spending $400 if I really don't need to.

Thanks

Nick

hr

So the total load is?

You mentioned 160 feet of total baseboard. This times say 600 BTU/ ft would be a total load of 102,000?

At a 20 degree delta t that would be a flow of 10.2 gpm. The head would be the 7 ft, or the highest pressure drop loop. So one 15-58 with zone valves easily fits this application. The curve shows 10 gpm at about 10 feet of head.

Sure each loop could have it's own pump a 15-58 on speed one at 7 feet will move about 3 gpm or 30,000 at 20°.

I have pushed a tad more than 67 feet, but that is still a good number.

If you use PAP you take a lot of fittings out of the calcs. Easier to insulate, also.

hot rod

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Ted_5

Witch boiler are you using

does it require P/S? If it doesn't, I would use 1 pump w/ zone valves for base loops and 1 pump for DHW. What is the total load? Can you use PEX for the sup/ret runs? Have you ever looked at Viessmann for a boiler? Do you deal with SPS company for your hydronic needs? Tim Laduke at SPS could help you out with sizing and design. Good luck!

Ted

Weezbo

Nick...

i am just a little bit curious ...what are the overall dimensions in square feet of your home? how much insulation in the ceiling (roof)? the outside walls? is there any vapor barrier inside the building? i think that it is commendable to use new products and all however i would like to fully grasp the whys and wherefores of your installation... it would help me make more informed choises in the future.

Waylon Lowery

Based on the picture

It looks like Nick is using a Condensing Boiler (Ultra, Munchkin, or perhaps a Vitodens). Based on that he will still want to use P/S piping to maintain the flow through the boiler. However, zone pumping on a baseboard system is overkill. I agree that zone valves and a single distribution (Secondary) pump should do the trick and help cut costs.

Nick_11

> It looks like Nick is using a Condensing Boiler

> (Ultra, Munchkin, or perhaps a Vitodens). Based

> on that he will still want to use P/S piping to

> maintain the flow through the boiler. However,

> zone pumping on a baseboard system is overkill.

> I agree that zone valves and a single

> distribution (Secondary) pump should do the trick

> and help cut costs.

Nick_11

> It looks like Nick is using a Condensing Boiler

> (Ultra, Munchkin, or perhaps a Vitodens). Based

> on that he will still want to use P/S piping to

> maintain the flow through the boiler. However,

> zone pumping on a baseboard system is overkill.

> I agree that zone valves and a single

> distribution (Secondary) pump should do the trick

> and help cut costs.

Nick_11

Total Load is

about 40,000 btuh. This is a 75 yr old building. It was unused uninsulated space until about 40 yrs ago when the piping and boiler were installed. 130 ft of baseboard in the apt and 30 ft in the garage below. The apt is about 640 sq ft. but most of the wall space is windowed (23 windows). Insulation is an ongoing, but probably only a 80% effective when complete, because of inherent structural limitations.

Because of the small space, the four loops upstairs will probably all be open at the same time anyway. The only loop that will really function as a seperate zone is the 5th loop in the garage. Having several thermostats in this small space wouldn't work too well. The kitchen, living room, hallway and end room are all open to each other. Only the bathroom and small bedroom have doors.

I plan on using a munchkin modulating, condensing boiler.

I also thought that I had to figure on all valves being open at the same time to size a single secondary pump. In that case I'd have head of about 23ft. and would need a bigger pump with higher gpm to pump thru all 570 ft of pipe.

So, If I only use one pump for the secondary loop, I still need one for the primary and also one for the Indirect Hot water heater. So, If I add 3 more pumps, one more pump for each of the uncovered loops, all my baseboard ft are under 67 and I'm between 3 and 4 gpm on each loop.

I was also thinking that I could run boiler at a little cooler water temp thru the whole 160 ft of base board which would allow cooler return and more condensing for more cost savings?

I agree, its overkill. The lengths of the runs, the 67' and 4 gpm rules of thumb (am I obsessed with them...) look like they lend themselves to the primary secondary system with smaller circulators. I don't mind spending an extra 400 - $500, (I'll be here for another 20-30 yrs.) as long as it works and won't cook my tenants.

I could cut some of the baseboard out. But Minnesota can be very cold. -35 deg. can/does happen. and it has the potential for disaster in an old building.

In fact part of my high "fear factor" is due to the tenant I just had in the apt. Last superbowl weekend, She left for a 4 day weekend and turned the heat down to 45 deg upstairs.

It turned out to be the coldest 4 day stretch in about 4 years. Lows between -18 and -24 each night with daytime highs -5 to 0.

No problems upstairs, but downstairs in the garage the main water pipe burst and the basement loop of the old boiler run also froze. I paid the price for not paying attention to the old system. That's why I want to replace the furnace; tear out, spray foam and replace walls before I get another tenant in there. I'll finish garage insullation this fall.

Nick

Nick_11

Insulation and Dimensions

The apt is 21'x32'. Only the attic proper insulation, Storm window reconditioning and unheated garage door are complete. The other items shown have to be completed this summer and fall.

23 older interior windows (even with good outside storms), and the perimeter attic problem described below make insulation difficult, expensive and probably only about 80% effective.

I tried to depict the "perimeter attic" problem on the attached sketch. Approx 28" of attic roof around the perimeter of the apt has the same slop as the interior ceiling and is seperated from that ceiling only by the width (3 1/2") of the 2x4 rafters. So I will have to take the beadboard off the walls and ceiling, have poly foam sprayed, then replace. All that for only R-21. I plan to do that in May. Am asking several more insulators if there could be any better workarounds without putting 2" holes in the beadboard walls, slanted ceiling.

This apt is a restoration of some great 1920's workmanship and I'm trying to stick with it as best I can.

I've gotten alot of good advice here more would be appreciated.

Thanks

Nick

Waylon Lowery

I'm not sure if you are calculating pump head correctly...

If you used zone valves your zones would be in parallel not series. As a result with all four zone valves open you would need 16 gpm but your head would not be cumulative...it would be slightly more than the head for your worst zone. Siegenthaler wrote a good article for PMMag on calculating head and flow for parallel piping systems. The math gets a little out of hand, but you'll get the point.

www.pmmag.com/pm/cda/articleinformation/features/bnp__features__item/0,,106650,00+en-uss_01dbc.html

jp_2

venting soffit?

don't you need to vent the soffit on this project? no worries about ice dams? I would fur out the 2x4 with at least 2x2 for more insulation and venting.

Weezbo

jp is saying....

you are insulating well enough in the basic h of it all however you will create a hot roof cold roof type situation...this is an old way to jolly up the venting where the insulation is over the exterior wall on the Tail sides of the roof trusses you can lay a 2" pvc pipe on the insulation and it will allow air to circulate up under the eaves to the crown.... then if you cut some large vents into the gable and Crown vent the roof you will cut down on the chances of undermining the insulation by condensate ..... basicaly there is a way to insulate in such a manner as to build an in wall climate as it were .... buildings gotta breathe or it will catch a cold. when it comes to insulation (foam that is) the first inch is doing the most. that is the rational of venting vs total insulation. were it fully insulated with no venting then everywhere would be the same kind of roof that is the way to insulate say a flat roof.3'- 4 " foam on the flat.