P/S is it OK New ?

Steve_45

OK Guys. I incorporated most of the suggestions, or I should say corrections, into my new layout. What do you think? Is it good to go?

Kal Row

JUST A SEC....

i thought you were going to go with 007ifc's - you need to be checked on both sides

also you got rid of the extra cross pipe – ok, but…, - do you have electronics that keeps the zone circulators off until the boiler loop is above 140 degrees? - otherwise the boiler is running coda and condensing corrosive flue gases, unless you are using a condensing boiler - the AFUE of cast iron boiler is done at 150-180 – but when the boiler runs cold it's causing internal corrosion and may also produce Carbon-monOxide because of localized rich mixture effects of gas impinging on a cold heat-ex – and the efficiency is 30%!!! - the DHW loop though, is usually not a problem since the load is already at 120 usually and the loop is small and comes up to boiler temp real fast - but the system can be cold for a long time – and, by forcing the zones off until the boiler is hot, your unfortunately precluding the use of 2 stage thermostats – the first stage of which just turns on the circulators and evens out the temps in the space and the second stage (kicks in 2 degrees lower) which actually calls for heat production from the boiler – studies have shown 2-stage to be the most efficient setup


that’s what I love about pri-sec-vari-speed injection a-la tekmar (the diag i posted http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=15880&mc=28#Message97583) – the boiler is fully protected with adequate water flow and no cold shocks or prolonged cold run, and no short cycling – tekmar boiler controls are the best thing since sliced bread – I wont install a system without it – and if and you ever install radiant – the tekmar 5xx series thermostats allow you to sense the room air temp, the radiant floor temp, and the outdoor temp at the same time, and do the perfect thing

hr

Better

the primary pump needs to be a check pump, also. When the indirect kicks on that (missing check will prevent backwards flow.

I don't remember if you mentioned what your emitters are? If they are low mass copper fin baseboard or panel radiators, I would not worry about return protection. Thousands of hw baseboard systems running with out return protection on cast boilers.

Radiant or high mass cast iron radiators, for sure you need protection.

A number of ways... A three way thermostatic piped at the boiler. A control that would shed loads as the return temperature drops (various tekmar boiler controls)

Viessmann uses a simple, non adjustable aquastat in the boiler that drops power to the primary pump when the boiler sees cold returns, on their basic cast boilers. Simple, but effective.

SOMETHING, SOMEHOW needs to watch and respond to temperature at the boiler return.

Kals idea is also a good one. Would require a different piping, however.

hot rod

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Steve_45

Getting confused.

If I understand what you are saying, I must have a means of sensing the return temp. at the boiler. This means should shut off all the circulators until the boiler temp. is
above a certain point. My understanding of the controls that I have is:
The Honeywell L8148A aquastat has one high limit set point. Let’s assume it is set at 180 degrees. There is a 20 degree delta(160). When the boiler temp drops to
160 degrees the boiler fires up. So if any circulator runs, the x1,x2 terminals of the Taco SR506-EXP will energize T1,T2 terminals of the aquastat. Therefore
if any circulator drops boiler temp. below 160 the boiler will fire up. I also thought that these new Boilers, with there low volume, heat the water real fast. Ideally with all loops of copper finned baseboard keep at under 67 feet of Baseboard shouldn’t that help keep the return temp good? The total length of the longest run is 110 feet total. All other loops are around 100 feet with
under 67 feet of copper finned baseboard.
If I am wrong can’t I just add the last 1 1/4 loop back and put a circuit balancer on it? And all circulators are IFC 007’s that should give me flow check at each end of the loops, Yes?

Kal Row

ok the ifc's are ok and ..

for the 4th leg, a circuit balancer is just fancy flow control valve – what you need is a THERMOSTATIC bypass system that’s wide open when the system is cold and slowly closes down as the system comes up to temp and is fully closed at 140

the aquastat on the boiler only turns it on - it doesn’t stop cold water from getting back to it - and the new loss mass boilers will rust out faster and also wont handle the cold shock as well, if the system is hot but on cold zone suddenly starts – only the DHW section is ok since the load on that is already warm – it’s just a question of getting it hotter – and worst of all the combustion is just not right on these things when cold

I put a system with an inexpensive slant-fin sx-150 but piped like my diag and it works like a charm – in fact the boiler is so isolated that it’s too hot – when the system goes off and the damper closes, the room cooks from the boiler’s heat – I recommend sealed combustion if you can, I couldn’t since I had too long and to close to wood, a horizontal run – but if you can, use their VSPH boiler, it’s much better – or you can go a more expensive and get the Burnham revolution or the Weil-McLain CV-gold both of which have built-in circulators that mix-down the output so the boiler is protected – further up is the Weil-McLain ULTRA and PLUS modulating and condensing, and at the top of the pyramid is the vie$$smann vitodens200 (though some of us like the munchkin better)

i highly recommend that you read - dan holohan's book “how come” and goto www.hydronicpros.com and buy ziggis book and software Special "Hydronics Design Combo" - and take a good look a the http://www.tekmarcontrols.com/literature.html site there is a huge amount of good stuff there

then, all our answers will make a lot more sense to you – maybe you will be able to teach us a thing or two – you have the whole summer in front of you – get educated first before you jump in and spend a fortune – heck – you might decide to put thermostatic valves and bypass tubes on each baseboard or get a condensing boiler and do it all differently

heatboy

Do you think you'll get.......

4 GPM through each of your 3/4" zones? That's what you will need if you are planning on a Delta T of 20°. What is the load of the building? It looks like there is too much boiler for the connected load. Short cycling may be a major issue, with what I see here.

hb

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Steve_45

Info

1) Yes I think I'll get 4 gpm thru each loop based on Calculations.
2) Total load now is 100,000 BTU. Addition
to follow in the future.
3) The 175,000 BTU figure that I put in the drawing was
what I read off of the Literature. Full info is:
Input: 175,000 BTU
Heating Capacity: 150,000 BTU
I=B=R Rating: 130,000 BTU
Do you think Short cycling may be a issue? If so, what can
I do before hand to avoid it?

Waylon Lowery

Keep it Simple

Steve,
In case you haven't learned yet, everyone is a critic. Everyone has different ways of doing things and different methods. You just have to strap on your BS filter and sort out the good advice from the not so good advice.

So with that said here is my advice, be it bad or good?

Short Cycling:
As far as short cycling goes, yes it probably will short cycle in the summer when you only have a DWS load. But it also depends on how you define short cycling. According to some, once every couple of minutes is not short cycling. To avoid short cycling you can either install a buffer tank or use a modulating boiler.

Condensing:
Based on my quick calcs, I calculated that your entire system will hold around 30 gallons. If the system is off for a long time and the water drops to 60 degrees, your boiler will condense in the time it takes to heat the water from 60 up to 140. Based on my 30 gallon calc, you will be condensing for about 8 minutes with a 150,000 btu/hr output. The condensate that will be produced in that much time re-evaporate, so I'd say don't worry about it.

Just remember the simpler the better.

Waylon

Kal Row

ok, but with that philosophy...

he can get rid of most of the stuff, all he needs is one pump (a 15-58 at top speed is enough), a supply header with 5 zones - the DHW being the priority zone that cuts the power to the other zone valves and done!!!

as for short cycling: i hate to be someone elses salesperson, nevertheless - here goes:

:<> !!! T - E - K - M - A - R !!! <>:

sorry for shouting - but i just wasnt getting through,
the tekmar controls make it all better and covers up a whole host of sins - where is Hydronics Mike Miller when i need him, he works for tekmar

D Peel

from Tokyo

As Hotrod suggested, IFC on both prinary circ and dhw circ, leave in the bypass or not. Your boiler is of a size where very seldom could it generate sustained flue gas condensation. Simply Enjoy............Dan

Kal Row

attached simplified diag

steve: is this a single family open house? cause if it is - there is no way you will need 4gpm per zone = more likely need 2 on the top floor, then 3, then 5 on the ground level, and back to 1 or 2 for below ground level

even though cold air drops - it stll seems colder at the ground level than below ground, in most i've encounterd

ALH_3

tekmar

I believe every system should have a tekmar control or equivalent. Kal's diagram will get you what you want a lot more simply than pumping every zone. If you really need the flow use a 26-64 Grundfos. I'd use the tekmar 260 to provide DHW priority and pump contact.

Kal Row

all wetheads should just sit down and read

the A Brochures at
http://www.tekmarcontrols.com/literature.html
not to mention all the good designdiags at
http://www.tekmarcontrols.com/design.html
everyone of their viso stensils can be disasembled
and reassembled at you hearts desire