Navien boiler not heating home.

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Old 12-19-13, 12:46 PM
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Navien boiler not heating home.

I had a Navien CH 240 NG installed the other week. Still working out some issues regarding it getting "dialed" in. Currently running at 180 temp, Tstats set at 72, not satisfying, only reaching 68 when its real cold outside (20/25).
Sufficient Insulation, but could use some tightening up and air leak intrusions fixed in home.
-(2) zones for 1900 sq ft, (2) more stubs in pipe design for future.
-Purchased Navien Manifold kit, instead of piping in primary loop
-(2) 007 Taco 1/25 pumps, 1 for each functioning zone.

Water Temp is 10 degree difference between supply & return, did not perform HLC.
Thinking water moving to fast or maybe zone valves needed?

I have to finish some wire dressing, bare with the pics- Thanks
 
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Old 12-19-13, 12:53 PM
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Who installed the unit?......

Ill have to breaze through the documents...

Is ODR hooked uP?

Is it making 180 out to the baseboards? ( Copper finned BB right?)

Does that unit have a built in circ for the boiler?
 
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Old 12-19-13, 03:40 PM
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Yes, what is the water temp that is going out to the rads ?
It might be you have too much flow across the closed spaced tee's and that 180 coming from the boiler is not actually 180 in the system loop.

Try to slow the flow of each zone, you did install globe valves right ?
Adding those other zones will make things worse.

What boiler came out of the system ?
 
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Old 12-19-13, 05:30 PM
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I think you piped it wrong. From what I see you need close space tees for each zone... That manifold was not needed..

In fact I dont think that manifold is for that unit at all... It shows no where in the piping schemes, and no way to get it to work IMO....

Page 25 here..

http://www.navienamerica.com/__DATA/...ment/2013/4/3/[2]_Navien CH-ASME Installation Manual_20130404.pdf

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Old 12-19-13, 07:13 PM
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Looks to be piped right using the Navien manifold accessory

But it's vented with PVC. Since it's not vented with CPVC or polypropylene I would question if the DIP switch programming is set to high temp operation.

Also what water temp did the old boiler run at? Perhaps it was hotter and required to be so due to the building envelope and the amount of heat emitters.
 
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Old 12-19-13, 07:21 PM
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Found it from their site

The manifold serves as a hydraulic seperator

http://www.navienamerica.com/__DATA/...ings%20v.1.pdf
 
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Old 12-19-13, 07:35 PM
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I could not find that document for the life of me..

Yes I would question the dip switches then...

Says...DIP Sw 3 of 8 Up (ON) in those instructions.....
 
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Old 12-19-13, 07:46 PM
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Should be # 8 of 8 On (UP) for high temp

Otherwise flue temp sensor downfires boiler to protect vent

Now you cant do this Faatim, unless the venting is changed to high temp.

Who installed this, can they read?

Pg 37
http://www.navienamerica.com/__DATA/ProductDocument/2013/4/3/[2]_Navien%20CH-ASME%20Installation%20Manual_20130404.pdf
 

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Old 12-19-13, 08:00 PM
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Now you cant do this Faatim, unless the venting is changed to high temp.
I dont think so... Thats with return temps higher then 140F... The unit is set for 125f from the factory and should not be touched....

Schedule 40 is fine......

Says nothing about supply temps...
 
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Old 12-19-13, 08:08 PM
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OK... Yeah I read the next page.

What will happen? I assume it will melt?
CPVC is rated for 200F? PVC 140F?
 
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Old 12-20-13, 03:28 AM
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Thanks for input!!!!

A burnham fired oil furncace (in ground tank) was pre-existing (25yrs old) 120 btu.
I was told via Navien & through a couple "friends of friends" that the manifold kit not only reduced labor/material cost, but also assisted with the units efficiency....terms like "mixing valve & reducing costs to heat return water" were thrown at me.

ODR not installed & dipswitches, both sets 6 & 8 were confirmed with Navien & manual.

PVC is currently being used, as opposed to CPVC. I did read that CPVC was recommended due to heat, but have heard & seen this installed w/ PVC.
I still may change.

Please be easy on me, as a buddy installed this with me (he's a plumber, Im a electronics guy).....$$ on labor not applicable post Hurricane Sandy.
I am going to re-read all your comments..THANKS

Tim
 
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Old 12-20-13, 03:42 AM
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A little more info....

I prob should install some type of temp gauge on feed & return side. I took a temp laser gun, which doesnt like direct contact with copper pipes apparently (covered with strip of tape) and shot temp from the feeds leaving 007 pumps and returns at zone drains. They matched what the unit is telling me at controller.

So we throttled back the system??? By shutting the return ball valves by half, meaning half open. Not sure if this "throttles" water back at all, some, or too much. There is an internal pump in the Navien, (5GPM?)
Looking into variable speed 007 pumps. But dont want to spend the money until I think thats the real problem.

Also, thoughts on insulating heating loops under a concrete crawl & basement. House is half & half. Worth the cost to insulate at $6.00 per 3ft section.

Thanks All
 
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Old 12-20-13, 05:02 AM
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They matched what the unit is telling me at controller.
and shot temp from the feeds leaving 007 pumps and returns at zone drains.


What were these temps????
 
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Old 12-20-13, 05:51 AM
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Feed/Supply at Taco Pumps 175 F

Return at boiler drains/ball valves 156 F

....thats after we closed return ball valves back 1/2 way to test water flow theory.

Thx!
 
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Old 12-20-13, 05:53 AM
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.thats after we closed return ball valves back 1/2 way to test water flow theory.
What are the temps if they are left open?
 
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Old 12-20-13, 05:56 AM
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which doesnt like direct contact with copper pipes apparently (covered with strip of tape
Not that it 'doesn't like' copper, just that the EMISSIVITY of copper causes errors in measurement, but you seem to have learned the 'trick' of using black electrical tape to get around that. (flat black paint is probably a better choice, but the tape is close enough for gummint work)

[by the way, it's not a good idea to anthropomorphize inanimate objects... they don't like it! ]

By shutting the return ball valves by half, meaning half open. Not sure if this "throttles" water back at all, some, or too much
Ball valves absolutely 5uck for any 'throttling' application. They are nearly impossible to adjust, partially closing them usually causes noisy operation (velocity noise), in constant use as a throttle, the internals will eventually erode from the velocity of the water as it is 'squeezed'.

The reason they are impossible to adjust is because the valve opening is most definitely NOT linear.

Fact is that closing them 'half way' will do almost nothing to affect flow.

To put things into perspective, somewhere around 90% of the throttling action will be found in the first 10% of opening from fully closed. Action is 'exponential'. Since this is a 90 opening valve, it means that you will have maybe 10 of handle movement from no flow to nearly 90% of the flow.

Bottom line... fuggeddaboudit ...

Flow throttling is best achieved with a PLUG VALVE (which I doubt you will find anymore) or a GOOD QUALITY 'HARD SEAT' GLOBE VALVE.
 
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Old 12-20-13, 05:57 AM
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I didnt take temps when they were open all the way, I just got the temp gun the other after I throttled the valves back. Im assuming I should try reading temps with them open all the way? (the temps seemed symetrical supply to returns with all the way open prior to closing halfway - couple days ago) I will take readings when I get home tonight.

Thx
 
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Old 12-20-13, 06:06 AM
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Thumbs up

Thx Trooper & Law -

I visited this forum (lurking in the background) reading your posts on boilers/heating systems for the past 6 months trying to get my "game up" for this install. So I appreciate the input.

Also, the old oil fired battleship would heat the house almost immediately, whereas the Navien seems to be a slow grower in returning heat to the home if heat was off. Regardless of ongoing insulation and sealing projects.
Home needs some updating.

Tim
 
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Old 12-20-13, 06:08 AM
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Feed/Supply at Taco Pumps 175 F

Return at boiler drains/ball valves 156 F
If you've got hot water going out to the radiators, and 20 cooler coming back, then there is no reason that you should not be able to easily heat the home.

Aren't the baseboards hot?
 
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Old 12-20-13, 06:37 AM
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Baseboards are hot, I did not take supply/return temp measurements with return valves fully open as yet

I just used recommended Slantfin HLC software. Using 140 water instead of 180 in program. It came back at 55,000- Not sure what to make of that.

1900sq downstairs
650 sq upstairs-uninsulated/currently renovating.
 
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Old 12-20-13, 07:34 AM
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I just used recommended Slantfin HLC software. Using 140 water instead of 180 in program. It came back at 55,000- Not sure what to make of that.
Changing the water temperature isn't going to do anything at all to the heat loss number.

The water temperature is used by the program when it calculates the amount of baseboard it will recommend be used in each room.

Which leads to the question... how does the amount of baseboard installed in your home compare to the recommendations of the program?
 
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Old 12-20-13, 07:44 AM
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Trooper,

Ok -got ya.
I plan on measuring tonight. (cart before the horse?)

The only issue I have with program was figuring out what type of baseboard I have. I noticed program prompts one to input either: Slantfin 15, 30, Multi pak 80 etc????
I dont know the difference.
I know I have 3/4 pipes & rads.
 
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Old 12-20-13, 08:00 AM
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The SlantFin 30 is more or less the 'standard' that gets used. The '15' is a lower output and the '80' is a higher output and more 'commercial' grade.

When in doubt, use the 30.

Did you keep all the existing baseboard when you swapped out the boiler? If it worked with 180 water before, it should work with 180 water now.

If you previously were used to fast recovery after deep thermostat setback periods... well... get over it! It may not happen like that any more. You may have to use shallower setback temperatures.
 
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Old 12-20-13, 09:43 AM
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One final Question,
My old setup (oil fired furnace) had 1 circulator pump & 3 zone valves.
Where now I have just pumps.

Is there a pro/con to either?
Im just trying to better understand the difference or need(less?) of each set up.

Thanks
 
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Old 12-20-13, 12:04 PM
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According to PVC Pipe and fitting manufacturers, Sch 40 PVC has the following ratings:
Maximum Temperature: 158F, 70C
Minimum Temperature: -13F, -25C
Melting Point: 176F, 80C
Tensile Strength: 6,500 psi
 
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Old 12-20-13, 12:12 PM
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Thanks Z-

Yeah Im not content with current PVC, although I was told "it will be fine".
In fact I read CPVC is recommended in manual.
Plan on swapping out in near future.
 
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Old 12-20-13, 03:48 PM
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My old setup (oil fired furnace) had 1 circulator pump & 3 zone valves.
Where now I have just pumps.

Is there a pro/con to either?
Im just trying to better understand the difference or need(less?) of each set up.
I think the bottom line is that it's more or less a Chevy vs Ford debate, and both camps seem to have equally sound reasoning behind their logic.

I'll throw out the ones that come quickly to mind.

CHEVY

Pumps may have an edge on reliability. You hear of more zone valve than pump problems by a large margin.

If a pump goes down, you still have heat in the other zones.

Pumps may use more electricity. (I say 'may use' because some of the new pumps are VERY efficient... but then, the MTBF (Mean Time Between Failure) goes down on them because of the extra parts...)

Initial cost for a pumped zone system is higher.

FORD

Lower initial cost to install.

Less electricity usage.

Less reliable.

=========

I'm sure I'm forgetting some of the important points but I would think this should get the debate started all over again.
 
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Old 12-20-13, 06:14 PM
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I like your logic & explanation there,

I am going to look into some type of water flow adjustment/pump device.
Due to mild temps tonight @ 9pm. The system is calling & satisfying properly, although still using 175/180 degree water. I would have to adjust manually on controller to reduce water temp if I wanted to, beings I don't have outdoor reset/sensor.

The system was satisfied when I went downstairs just before, which I felt feed lines to both zones, Slightly warm. Then a zone called, which within a couple seconds the feed got hot. BUT I'd say within 20 seconds the return was real hot too. Considering the length of that 1 zone through 5/6 rooms (Living/Dining/kitchen/Laundry), that seemed to be awefully fast. Maybe too fast.

Either way, Im going to monitor the system during the next few days. Taking some temp values, play with return valves & monitor flow times & look into Outdoor sensor.
Thanks Again all-
 
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Old 12-20-13, 08:16 PM
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I'd say within 20 seconds the return was real hot too. Considering the length of that 1 zone through 5/6 rooms (Living/Dining/kitchen/Laundry), that seemed to be awefully fast. Maybe too fast.
Consider that the water would be moving at around 4 feet per second, would that be consistent with the amount of time it took for the returns to get warm?

If you're circulating 180F water and the home still isn't heating, it's not the fault of the boiler.

Did you keep all the existing baseboard when you swapped out the boiler?
Have you checked yet to see what the SF program suggests is needed for each room vs what's installed?
 
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Old 12-21-13, 06:43 AM
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How many lineal feet of radiation do you have? Measure just the length of element not the cover. If indeed the heat loss is 55k the boiler from what I read on other sights is close to max output. I have read the Navian output @ 4 GPM is about 60k. If the radiation is close to the heat loss you may need higher temperature.
 
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