Boulderz - problem with check valves

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Old 01-29-14, 07:24 AM
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Question Boulderz - problem with check valves

Forgive me for jumping in to this thread, but I've been researching solutions to a heating question and this thread seems relevant...

I have a Laars propane fired baseboard/radiant hot water system. I have 4 baseboard zones, 2 separate zones on 1st floor, 1 on second, and 1 on 3rd. I have 2 radiant zones in the basement.

I am getting heat to all 4 baseboard zones (maybe radiant too, not sure) regardless of which thermostat calls for heat. The 4 baseboard zones have Taco flow check valves installed on the supply side. Plumber and I thought they were bad and replaced all 4 yesterday. However it did not fix the problem.

Circulators do not have IFC valves.

Any ideas to what may be causing all 4 flow chck valves to open when one thermostat calls for heat??
 
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Old 01-29-14, 07:37 AM
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Couple questions for you boulderz...
Has the problem always happened? or did the problem just start? how old is the system and was anything recently modified?
 
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Old 01-29-14, 07:41 AM
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We just bought the house this summer so this is the first heating season. So I have to assume it has been happening for awhile, former owner was older woman and probably wouldn't have even noticed. The house was built in '92 but the boiler was new within the last couple of years.
 
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Old 01-29-14, 04:31 PM
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Are you sure the check valves are in the proper location on the system?

It could just be a case of improperly designed piping.

Can you show us pics?
 
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Old 01-29-14, 06:20 PM
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Here's 2 photos of the setup.
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Old 01-29-14, 07:06 PM
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OK, that's a start.

Do you have a real camera? If so, please use that rather than the cell phone. Try to get some lighting on the setup so there aren't as many shadows.

I'm trying to see how the piping is arranged but can't really figure it out ... too many missing pieces.

Can you possibly draw a piping diagram and post that?

From what I THINK I can see, there's nothing that would stop any one of the pumps from 'pushing' all of the check valves open.

The pumps are pumping INTO the RETURN on the boiler, right?

So when the water comes out of the supply, it's pushing toward the flow checks in the direction to open them, isn't it?
 
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Old 01-29-14, 08:24 PM
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I can do a diagram and get better pics soon. But to answer your question, yes the circulators are pumping into the return and water is being pushed toward the flow check valves in the supply.
 
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Old 01-30-14, 06:55 AM
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Here's the schematic of the system.

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Old 01-30-14, 07:53 AM
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Radiant Z1 and Z2 ... are they piped like that? on a pair of tees spaced closely together?

Are there no check valves on the radiant zones?
 
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Old 01-30-14, 08:22 AM
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Yes they are piped like that, except there's a mixing valve piped in. See attached. It's the 2 circulators far left, supply comes in from ceiling down and it seems to me the circulators push through the zone. I wondered why the returns are tee-ed to the supply, but maybe that's how it's supposed to be. There's no flow check valves on the radiant zones.

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Old 01-30-14, 08:25 AM
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Update, I just checked and those 2 circulators have Integral Flow Checks...
 
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Old 01-30-14, 03:33 PM
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That's actually a pretty pizz poor way of piping up those mixing valves.

We'll get to the flow check issue, but I want to go over a few other things first so I understand the whole system.

There are temperature gauges on the two radiant supply pipes off the pumps.

When the radiant zones are calling for heat, what temperature water are you running in those loops?

Is the radiant tubing embedded in concrete slab? or attached to underside of wooden floor? (you said basement so is it safe to presume in concrete?)

There are two Taco control panels... is each one running three zones? Or is it split so that one runs the baseboard and the other runs the radiant?
 
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Old 01-30-14, 03:57 PM
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The problem is the Laars EDP has a internal pump and the boiler is connected in series, so the boiler is going to pump hot water around all the zones no matter what.

1) The drawing needs First floor Zone 1 -- return moved to the right of both the radiant returns.
 
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Old 01-30-14, 04:08 PM
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HW, I didn't think to look at the boiler manual... if what you are saying is true, then your point 1) is really irrelevant bacause the WHOLE THAM DING needs to be repiped... no?

It appears that this should have been piped as PRIMARY/SECONDARY.

Boulderz, what is the FULL MODEL NUMBER of the boiler so I can look at the correct manual.
 
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Old 01-30-14, 04:22 PM
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Looks like one manual covers all models, here is what I found:

http://www.laars.com/LinkClick.aspx?...edownload=true

Yes, that boiler is piped ALL WRONG. Sorry for the bad news.
 
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Old 01-30-14, 04:59 PM
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Well I'm impressed. Thank you both.

Now tell me what the hell that means.

@HW "1) The drawing needs First floor Zone 1 -- return moved to the right of both the radiant returns." Yes - you are correct, I drew that wrong. Zone 1 is to the right of the 2 radiant zones.
 
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Old 01-30-14, 05:16 PM
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Old 01-30-14, 06:06 PM
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Now tell me what the hell that means.
What it means is that you will never be able to stop the flow to all zones unless the solution starts with a Sawzall.

It would end with an installer actually reading and understanding the manual and putting it all back together properly.

The point about the return on zone 1 is meaningless...

Sorry to be blunt, but that's the way it is.

Look at the manual, Figures 20 and 22 are relevant.

Primary/secondary is a piping technique that is used with this type of boiler system.
 
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Old 01-30-14, 06:39 PM
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Well I've spent the last hour or so reading the manual and the Laars "Approach to Primary/Secondary Systems" and I understand how it should be hooked vs. the way it is now. Very interesting stuff. So basically each heating zone becomes a tertiary zone to the primary (boiler), and secondary (constant loop). The circulators will need to move to the beginning of each zone off the secondary and the return must be within 12". Sawzall indeed.

So what is it that causes the Flow Check valves to open now when they're not supposed to exactly? Maybe I don't understand how they work. I thought that when a circulator turned on downstream of the flow check the pressure change would open the flow check. Is the integral circulating pump in the boiler pushing them open from the supply side?
 
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Old 01-30-14, 07:06 PM
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Is the integral circulating pump in the boiler pushing them open from the supply side?
Yes, exactly.

When ANY zone calls for heat, the internal boiler pump runs.
 
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Old 01-31-14, 02:28 AM
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Is it possible

Assuming he has the minimal flow through the boiler when the smallest zone is calling, to just pipe in a differential pressure bypass valve?
 
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Old 01-31-14, 07:33 AM
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No, that won't work...

There's not 'minimal' flow through the boiler at any time because there is a pump internal to the boiler that provides much more than minimal flow...

In other words, in addition to ANY zone calling for heat, and it's respective pump running, there is ALSO another pump 'in series' with it. This second pump is 'over-running' the check valves.
 
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Old 01-31-14, 12:28 PM
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Assuming he has the minimal flow through the boiler when the smallest zone is calling, to just pipe in a differential pressure bypass valve?
No the Laars is a low mass integral fin copper tube boiler just like a Lochinvar or Raypak. It must have a continuous flow of water across the heat exchanger.
 
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Old 03-06-14, 06:03 AM
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Followup

I spoke with the plumber and tried to squeeze some advice out of Laars support. The plumber seems to think "a few closely spaced tees" would solve the problem.

Laars stated "Re-piping this as a primary/Secondary system with the boiler connected to the system piping with a pair of closely spaced tee's would make the situation much better, but I'm not sure it will correct all the issues you may be having. "

That statement from Laars is disconcerting because unless i'm mistaken, they are suggesting even plumbing this the correct way will not solve all of the problem??

Any advice out there? In other news I will be starting another thread discussing an issue with moisture under my radiant/raised subfloor...
 
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Old 03-06-14, 09:29 AM
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That statement from Laars is disconcerting because unless i'm mistaken, they are suggesting even plumbing this the correct way will not solve all of the problem??
They're covering their butts...

They can only base a response on what you told them, which they know may or may not be the truth, the whole truth, so help you God... they can't SEE the system to evaluate for themselves the sins committed by your plumber... nor can they guarantee that your plumber who throws in a couple closely spaced tees is going to do that properly... see how he screwed up at his first rodeo? Why think he'll do any better on his next bronco?
 
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Old 03-06-14, 10:24 AM
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Would a couple of closely spaced tees, as the plumber said, achieve a primary/secondary setup? Or is that a stopgap from replumbing the whole system.

At this point there will be no plumber, that is now me, and I plan on redoing it after heating season is over. I'm just trying to figure out the best way to do it.
 
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Old 03-06-14, 03:09 PM
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I think the easiest answer to this is to say that the system needs to be installed per the manual.
 
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