Is constant circulation OK?

Joe_85

[IMG]http://i45.photobucket.com/albums/f95/leoncrooks/DRAWING.jpg[/IMG]


I made this drawing, which I hope shows up, to show what they did. If it doesn't show up, I'll try something different.

I put a letter "T" for each tee they put in. I indicated the primary pump and its pumping direction, the cold feed, expansion tank, the 2 secondary circulators and their direction of flow, the load (house & garage), and the supply and return side of the munchkin.
All I left out is the superstor tank and it's plumbing.

Joe_85

In slab circulation

A co-worker of mine had a new house built-Pex heated concrete slab (insulated), wood frame, steel sided, with a munchkin 140m installed. Garage one zone, house another.

The vision one certified contractor- who is normally a forced air type of guy- put this system in and they are not having much luck. I think he passed the course, but doesn't grasp hot water heating.

I have been out to look at the plumbing one time, and I believe it is all wrong. I traced it all around from supply to return, drew arrows on the pipe for myself to show flow direction and from what I see he did....not good. That is another discussion for later.

They did a half-ast primary-secondary but didn't get the closely spaced tee thing right. I know how they should work, and this one isn't performing. Short cycling is his big complaint.

But, I digress. I drew him up a schematic of what I think the system should be plumbed like, but I gave him the copy of Seigenthaler's Hydroninc heating book and haven't got it here to look thru- thus this question.

My question- is it, generally speaking, good to have the water circulating constantly in the slab when the house isn't calling for heat- in a primary-secondary system.

I figure it's best this way- that way there is not a big slug of cold water hitting the boiler at start-up after a call for heat. The floor will stay at a uniform temperature, no more heat emitting from the floor until a call for heat.

What do you guys think.....Joe

kevin coppinger_4

classic answer....

would be ...It depends. If the system is properly designed and has the proper controls, Yes constant cirulation is great. Weather respaonsive rampup and down is probabaly the best way to go. But if his ratios are all messed up and sensors are in the wrong place results will stink...classic quetion..got pictures? Where is the job? What has the contractor said? kpc

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Couderay

Primary/secondary

Go to HTP transfer's web site to see their layout on primary/secondary. What you have drawn is not P/S. I really don't see how that system could work (drawn).
http://www.htproducts.com

Christian Egli_2

Heat spread thin is the key

Water heat is fascinating to watch being spread around a home. Water, due to it’s tiny heat carrying capacity does not get to move your pile of BTU around in one big back breaking haul. This is in total contrast to what steam does. Steam flies off the boiler with a boat load of heat and goes around dumping it everywhere in your home, after that, it’s finished, steam does not either smooth out your heat, nor does it irresponsibly bring it back to the boiler or the colder piping. That’s just that, steam easily achieves natural balance uniformity and comfort without much coercion.

Hot water can’t make effective single loads of heat, it goes about it in a different way. Where hot goes to cold, there is a constant ebb and flow of tiny waves of heat, and so, whatever skirts out of your boiler has to be massaged for a long while until it is nicely spread out over the entire floor, like peanut butter on sliced bread. The result is quite tasty and very comfortable, but it takes work and it takes control leadership.

Constant circulation is important for ironing out all the lumps of heat, particularly in massive floor heat. Primary/secondary couplings are important in keeping the heat pointed in the smart direction. Sophisticated controls, reset and outdoor sensors are important in getting things organized for effective heating. All this isn’t free, of course, but it is the cost getting efficiency out of hot water and great comfort.

Constant circulation will help even out your complaints, but I’m not sure whether it is the main actor in your short cycling, more of your control scheme has to be smoothed out for total comfort. But in any case, planning on constant floor loop circulation breaks down the problem into smaller and more manageable parts. Then you can go on increasing the temperature bandwidth on the boiler - if that’s what’s causing irrational short cycling. Perhaps fiddling with the reset curve is all that’s needed. You don’t mention mixing valves or injection setups to give you trouble either. Is there even a sufficient amount of coil length?

Good luck, winter is spreading itself thin so far.

A.J.

piping not right

Joe you need to reverse your supply and return but makesure your return is on the right side of your boiler return.

Ted_9

Unbelievable

There are good piping diagrams in the munchkin install manual.
Why don't people look at them?

From looking at you drawing, it looks like every time the boiler is called to fire, it would rob the heating circuits of any hot water. Then, after the boiler shuts down, the heating circ take any available hot water.

That piping set up will not work and should be reworked.

Massachusetts

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[Deleted User]

Slipping clutch syndrome...

Obviously, that hand drawn system schematic is missing numerous components, intentionaly left off the drawing, or possibly not.

As drawn, unless both of the heating circs are on, water being like my ex brother in law, is wet lazy and stupid. It will follow the path of least resistance. Hence, if only one pump is on, then instead of following the anticipated path back to the heat source for another ride and to pick up additional heat, some of it runs backwards though the OFF zone, thereby creating a bypass, causing the slipping clutch syndrome.

Best suggestion I can make echos everyone elses. Follow the manufacturers recommendations. Continuous circ has to be designed into a system. You can't simply turn pumps on and make them run all the time and expect the problems to go away. It may eliminate short cycling, but it will probably cause overheating to occur, which is the number one complaint from people with improperly designed/installed hydronic radiant heating systems.

And before Chris jumps in here and starts with his negative Munchkin schpeal, it doesn't matter WHOSE product is installed, if it is improperly applied, there WILL be problems. Even a Viessmann won't work right if misapplied...

ME

Weezbo

the water goes zing right out of the boiler thru a piece of pipe

Bang right back at the boiler.

i could theoretically see how that might be short cycling

Unknown

passed what?

Furance guy passed what test? Pay the money and u passed!.... Your co worker needs to hire a real BOILER pro and have it repiped correctly and summit the bill to the furance guy so he'll know that he "passed"....

Bob Sweet

I agree with Ted

htp's installation manuals are nice, very specific on piping requirements.

Not trying to beat a dead horse, but the drawing you have looks nothing like the Munchkin req. I can't see it working as drawn.



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Joe_85

Joe_85

Nothing left out...........

No, I didn't leave anything but the superstor out of the drawing. I didn't simplify it any, it is just like I drew it. Like I said, I know that it isn't right but that is how it's laid out. The homeowner told me that this the contractor has replumbed the near boiler piping twice, and still can't figure out what's wrong. That's why I went out to look.

The installing contractor is no fly-by-night guy or a moonlighting plumber, it's just that hydronic is scarce in these parts and I just don't think he understands all the intricacies of the hydronic systems- Pumping away, closely spaced tees and all the other bits which make a system work.

We hydronic users here in S.E. Kansas are basically on our own. I only know of 3 people in my town who heat hydronically- besides my coworker. 1 has slab heat, I and another have baseboard- all self installed systems. 1 has a waste oil fired outdoor boiler, 1 has wood fired outdoor, and I have a Munchkin/Outdoor Wood fired combination. All percolating right along saving us money!

Anyway, I know the drawing in the Munchkin booklet is good, that's where I got the idea to make my system pri-sec. The homeowner I speak of isn't savvy to this kinda stuff either, he knew I knew some about it so he asked me to come see what I thought. If I could be out there when the contractor comes back, I have no qualms about sharing my knowledge and I'd even help them do the plumbing so they'd get it right. I'd like to see the guys system work.

That's the reason for me wondering about constant circulation being a good idea. I'd hate to tell them to try it if it wasn't practical.

Weezbo

Joe, you can ask anything about these boilers or piping

arrangements that you would like.

if you look at the system an see minor technicalities in the piping and honestly do not feel comfortable with what you are looking at at the time post a jpg and you will get all kinds of help here.

thing to do is get a clear idea of the radiant system that is installed...look for things like type and length of the tubing or pipes and write any numbers that you see written on the outer covering..it may be that there are things that you do not see that are every bit as difficult to comprehend when you first looked at the boiler piping. there are ways to pipe various emmitters and then there are ways to pipe them ) and man oh man ! sorry...piping primary secondary is one option..with a modulating condensing boiler you are having other options ,Too.

i am timing out alot as i have pain fingers that dont know asdf jkl; worth a darn i know it sounds like i am sniveling thing is though , you got to start somewhere and this is a great place to start.

GW

pretty sad

Wow, that's a nasty set up. Flip the two system circs and it will work better.

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[Deleted User]

Do it this way...

And if properly programmed, it will work like a champ. If your contractor doe snot understand the V-1 programming, have him call the local rep, or get back to us here.

Properly installed and programmed is the key to comfort and efficiency.

ME

Maine Doug_59

Your diagrams

are works of art in themselves. Gives a new dimension to "a picture is worth a thousand words". Thanks

[Deleted User]

Credit given where credit due Those diagrams...

are from HTP's web site. I just "borrowed them" and pasted them here for his edification. John Siegenthaler actually generated the originals. Thanks for the kudos anyway:-)

ME

Kevin G_2

boiler piping

Joe
I see a way it would work but i dare not say it. best bet is to repipe the secondary. the primary is fine but you have to move the the air seperator and put both pumps on the supply side. the supply must be moved to the right out side the closely spaced tee's (within 4 pipe diameters) Also what size is the piping that was existing. no mention of that in your post's. Primary must be 1 1/4" same size as fittings on the boiler. last thing you will not shock this boiler brining ice water back to it. we run these on snow melt system's here all the time. also should have check valve's to stop any flow that is not desired. where is the piping for the indirect you could have issue's if the check valve's were left out.

Kevin G