Problems Unresolved, Seeking Input {Looking for References, Chicago Area -- Mod Con Boiler}

4xlt

Hi All,

I searched and didn't see any policies prohibiting this, so here goes and my apologies if this kind of inquiry is frowned upon.

We live in the Chicago area in a 1920's brick house with a rear addition done in the late 70's. We put in a wall-hanging mod con boiler from a well-known maker a couple years ago when we bought the house. Most of the house has cast iron radiators -- the main zone. The addition room (~ 15 x 20) has radiant baseboards -- and lots of window surface area -- the second zone. Some new piping was done to move supply and return lines near the unit but the existing radiators and baseboards stayed. The new boiler makes our DHW and sends it to a reserve tank -- the third zone.

The heat works fine in all the rooms with old radiators in the main zone. We have truly poor heating in the addition room. We have had numerous lockouts and blocked errors. The greatest frustrations have come from our experience with the company who did the install for us. They are a relatively large, well-regarded, very long established company in our area, they weren't the lowest bid, they are responsive and they are nice guys but they have basically shrugged their shoulders about adjustments to the equipment and system, and it still wants to go to lockout and blocked modes anytime the outside temp gets below about 20 degrees. After numerous 2am visits of "we'll try this and see what happens," they now freely say they don't know what they would try next.

There has been some discussion that the addition's baseboards are inadequately serviced. Of course there's that whole we paid a bunch of money for the work, why didn't you even once mention there might be an issue with the existing baseboards question that hasn't helped our confidence level with the contractor.

We understand these machines can be tested by computer for performance, but neither our installer nor the boiler's regional contact who has come to our house wanted the conversation to go that direction. Hey, whatever, we'd just really like to find someone who REALLY knows what they're doing with these systems and understands how to properly integrate it into an older house with radiators in place.

We are looking to tweak the settings if possible, to enhance the setup in the addition room if necessary, and we're also looking to add a zone to the large, currently unfinished basement that is entirely without heat and radiators. I suppose the huge 1940's converted-from-oil boiler that we removed was itself the basement's heat source previously.

So we're seeking references for people in our area. We realize from experience that someone who is a good general heating contractor isn't necessarily going to be the right person. We hope to find a specific high efficiency boiler guru, savant, wiz or the closest thing we can get. Hopefully there's a professor, mad scientist or safe-cracker type guy out there who has particular knack for these machines that we can connect with.

Thanks in advance to anyone with good suggestions.

Chicago area/northern Cook County

nicholas bonham-carter

post some pictures of the boiler and its piping, and you will have the attention of the finest in the field.--NBC

Abracadabra

I can probably recommend some hot water heat guys.. I have my hands full with steam. I'd be interested in finding out who did the work, since I know of 4 very well known companies in Chicago that do hot water heat. Hopefully not one of them did the work on your place. I'd have to scratch them off my list.

Jon.rcsales

I would love to see some pics of the installation and maybe I can help.

SWEI

Did anyone perform a heat loss calculation before they decided how much baseboard to install in the addition?

4xlt

"Did anyone perform a heat loss calculation before they decided how much baseboard to install in the addition?"

Thanks -- Baseboard units were installed in the 1970's when the addition was built and were not replaced when we put in the new boiler, but the sales technician did calculations on the whole house for the quote. We got SpacePak air at the same time from the same outfit and I discussed the process with the guy while he was measuring all the rooms and windows. How well he calculated is in question. He said the baseboards would be fine as-is. Now replacing the baseboards is one of the two options they have suggested to help stop the lockouts and blocks. The other suggestion is an expansion tank for the (dedicated) loop that serves the addition.

Clearly I'm not prepared to pull the trigger on either option just based on what they are saying since these guys have shrugged their shoulders on any useful boiler setting adjustments and it seems like they are doing more guessing with these suggestions.

I have some pictures of the install and I'll post one next.

4xlt

Picture of install

4xlt

Original builder's layouts with some armchair editing. Rads and baseboards in red. Blue star marks the approximate location of the boiler unit, though it's in the basement which is mostly open.

2nd floor is 1/2 story -- Chicago bungalow style house

Paul48

They seem to have taken pride in their work. They just don't read well.

SWEI

Is this a WHN or WHL boiler? If so, they can be piped direct in many cases, but the installer really does have to do the math.

4xlt

WHN model

4xlt

All the help offered is very much appreciated. My main goal is still to get some references to pros in my area who are very knowledgeable with this type of system.

To further the discussion, some more information:

The heating from the baseboards was sufficient with the large, old boiler. The heating from the baseboards has not been sufficient at any time since the new boiler was installed.

The supply and return for the baseboards (only) is 1/2" copper.

The boiler seems to indicate that most or all lockouts and shutdowns are due to 190 degree temps being reached within the boiler.

Installer suggests the baseboard lines are too small, saying that therefore too much heat stays in the water in the return. (really?)

Setpoints for the heating zones were at 150 degrees initially. The one thing I did entirely on my own was to lower the setpoint of the baseboard zone to 148 degrees. After that lockouts were reduced from frequent to rare occurrences, but they still happen, especially when outside temps fall below 20 degrees. I didn't go any lower because I don't really know what I'm doing and the room isn't heating up anyway.

My guess is the old boiler pushed a higher temp through the baseboards and didn't care what the temp was on the return, and that the baseboards can't heat the addition at 148 or even 150 degrees. However I'm not yet buying into the installer's suggestion that larger diameter lines would solve the problem.

It seems to me that larger diameter lines of the same length that we have now, circulating at roughly the same rate of flow at 148-150 degrees isn't going to make the boiler stop shutting down and probably won't make the room that much warmer.

My uneducated thoughts are that the flow rate either needs to slow down -- and can't such a fancy machine be adjusted for this? -- or there needs to be significantly more volume of heated water with greater surface area in conductors in the room, or both.

Again, thanks to all for any help offered.

4xlt

{Still looking for references}

So do I understand you correctly to mean that there is too little flow in the zone?

The zone in question is served by the green Taco on the left in this attached photo, and all three circulating pumps are on their zone return lines, within inches of the boiler inlet. You'd think this would push through pretty well?

The total linear feet of pipe in the troubled zone is probably less than 100, and the vertical distance above the boiler is never more than about 2 feet.

If it means anything, the volume of water involved in the baseboard heating zone is miniscule compared to that used in the main heating zone. The baseboard zone heats 1-2 rooms and the main zone heats all of the rest of the house via large multi-sectioned radiators.

Another thing I recall now being said was that the difference between the inlet and outlet temps was remarkably high. They made some adjustments on the boiler settings to force it to pause at certain times in the cycles but it didn't seem to make a difference to the lockout/shutdown issues, and of course it didn't make a difference to the poor heat situation in the baseboard zone.

SWEI

Hatterasguy said:

The new boiler probably has a much higher head to overcome as compared to the old boiler and the flow rate via the 1/2" piping is just not sufficient.

Sounds like you are new to firetube mod/con heat exchangers. I'm not sure what size WHN this is or what flow they are trying to move through it, but most of them have less than two feet of head loss at design conditions.

unclejohn

I never pipe through a mod con boiler with less then 1" pipe through the whole zone. Anything under 1" is gonna have to piped P/S. Like they used to say on Drag Net "thats just the facts Mam."

RobG

If I were in your situation I would buy a low loss header and have it installed per the instructions, In-out, In-out. It's hard to do wrong. If the installer has any questions just send him or her here.
http://www.caleffi.com/usa/en-us/catalogue/sep4tm-4-1-hydraulic-separators-549506a

4Johnpipe

I would recommend a buffer tank that would also act as the hydrolic separator and allow the tank to be the call to the boiler. The older radiators will take up the slack of cooler than designed for water temps while the newer baseboard is suffering due to I'm relatively sure is a cooler water temp running through that zone. Just repaired a 2 year old system that had similar problems. I would also add VDT circulators to keep the delta T in the series baseboard loop.

Rich_49

Still looking for a contractor ? Use the find a contractor feature right here on the site .
Seeing how your boiler is piped , not optimal , Not uncommon .
Call the installing company and have them replace the baseboard circ with a high head low flow model , possibly a Taco 009 , the 007 that is there IS NOT enough pump to do this series loop and keep the boiler happy . You say the baseboard is 1/2" piping , that appears to be roughly 70' of baseboard and supply and return piping puts you north of 100' of 1/2 piping and emitter , add to that the head needed for the boiler which the old boiler did not have and you have your answer . You could also tell the installer to visit this site and begin his education so he knows next time what to look for or do .
As others have mentioned , a hydraulic separator or small buffer tank would be a real good option also and will maximize the efficiency of the equipment you invested in . It will require another pump also .

4xlt

So the saga continues. Bringing this back up to pose more questions. One person on this board, in particular, was very helpful to me, but unfortunately the trade reference he gave me didn't call me back. I will likely ask again through the referrer, but in the meantime I have been talking to the company that did the install and they want to make things right.

Problem is, I don't believe they have the expertise with mod/cons to actually make it right, as much as they might want to. The guy who sold me the system had been there something like 12 years but of course now he's gone. I'm working now with a very customer-focused guy at the same place.

Where we are now is trying to figure out exactly what they can do to fix the system, preferably within the bounds of what I bought in the first place. Unfortunately I believe they are still feeling around in the dark to some degree.

They have agreed to come back and re-pipe the near-boiler lines and add a pump to make the setup primary/secondary to match the manufacturer's suggested specs for the design. Whatever else, if anything is eventually done, the primary/secondary piping will happen.

We're also not getting anything close to "endless" hot water from the indirect DHW (TT, 40gal). We have below-average hot water usage and no high-flow bath plumbing. The water temp starts to drop after about 7-8 mins in the shower with no other hot water appliances operating. It's been suggested that the DHW zone pump (Taco 007) may be incorrectly sized.

The biggest problem remains the lack of sufficient heat in the small zone, Zone 2, which again is all baseboard. ("Family Room" and "Breakfast Room") Those two rooms combined have about 75' of 3/4" copper-piped baseboard, but about 25' of 1/2" supply and about 25' of 1/2" return. In two places where there are small gaps in those baseboards, they are connected with 1/2" copper. Before I got fed up with the constant lockouts (5x per night when outside temps below 20F) and lowered the setpoint temp in this small zone, it was set to 165F. It never worked right at this setting. The previous boiler was a very old behemoth -- like 1940's -- converted from oil. The house initially used coal heat.

I found the original MJ8 calculations and attach them for those who are willing to review. I've added some notes to the worksheet in blue and red.

Floor plan images and install photos attached to previous entries in this thread.

At this time, I welcome comments to the sizing of the boiler (Lochinvar/Knight WHN 199) to the design and suggestions for the appropriate pumps.

Existing details, summary:
Lochinvar/Knight WHN 199
Triangle Tube Smart 40
Taco zone controller SR 503
Zone 1 pump -- Grundfos 26-99, 3 speed
Zone 2 (small, problem zone) -- Taco 007-F7
DHW zone -- Taco 007-F7

Keep or change any of these pumps?

What pump for the new boiler loop?

Then I still need to find someone to dial in all the settings.

Then when it starts working right (?!), we want to add heat to our currently unfinished basement. I can't even think about that until the existing system starts working right.

Again, any help is appreciated.

Gordy

1st your problem zone with the 1/2"supply, and return piping to 3/4" base boards. 1/2" pipe carrys around 15000 btus where 3/4" pipe carrys around 42000 btus. Your heat loss in the problem zone is way above 15000 btus like all most 25000 btus. The pump would be fine with proper sized supply, return, and inter connecting piping.

Thats also why the boiler was locking out not enough flow for the HX. Thats a big boilerfor the heat loss with tat HX comes a minmum flow rate if th flow rate is to low the HX over heats, annd locks out. With1/2" piping in that zone, and only that zone calling your done.

4xlt

Thank you very much -- changing out the old 1/2"-piped portions for 3/4" is being discussed now and will most likely happen.

So do I understand correctly that the Taco 007 would be the right size for that small zone if the entire loop were 3/4"? I ask because earlier in this thread it was suggested that the 007 was too small for the existing 1/2"- 3/4"-1/2" loop, and I'm not sure what making the entire loop 3/4" means in terms of pump output needs.

Also, any suggestions for the pump to use on the new near-boiler loop that will be added? Suggestions about the insufficient DHW supply?

Gordy

The 007 will work with 3/4" piping changes. As of now no with 1/2" piping Rich covered this earlier. You still need to deliver the btus Rich did not have that info in his earlier post.

The 26-99 is the pump that comes with the WHN 199 yes it will work for the primary loop change.

4xlt

A detail I forgot to mention about the WHN 199: The install was 3 years ago next month, and the cycle counter is now over 75,000.
Oversized?

Rich_49

I would suggest some sort of Delta T pump for that zone so the AWT can be guaranteed . Series circuits are a pain in the **** and more often than not end up with a very high Delta and colder water back to the boiler . this is not a bad thing with a mod con but very bad for baseboard output considering or assuming there is probably not enough of that installed . This is normal many times . Control that AWT in those 2 zones , 1 pump , 2 zone valves . You will not have another problem later if this is addressed now .

ced48

4xlt said:

A detail I forgot to mention about the WHN 199: The install was 3 years ago next month, and the cycle counter is now over 75,000.
Oversized?

This detail is really important. In my humble opinion, the boiler is cycling on and off at an unacceptable rate. I would expect to see a number like 7,500, not 75,000, after a 3 year period. There is something out of kilter here, may be an oversized boiler, or the way it is set up.

4xlt

Thanks Rich -- bear with me here...

In your last post I thought you started off talking about a variable speed pump for the small, problem zone, then it seemed you went to talking about changing from zones with separate circulators to connecting the two zones, adding zone valves and circulating the whole house with a single 26-99.

Would that mean we'd then have a single-temp system? We have two thermostats now and I thought we are set up with multi-temp system, though I have wondered whether we actually do have one.


I'm not contradicting, I just don't know enough and I didn't follow what you were trying to convey. Might you clarify?

Gordy

Oversized? 199 for a 79k heat loss. Zoning................Holy crap better change the batteries in my key board or proof read a little more.

4xlt

Thanks Ced -- yep, 75,000. Three zeroes. The thing is running all the time outside of warm season.

Gordy

Can you get us a length of base board, and type(pic) in the problem zone. The heatloss dictates 53 btus a SF thats ridiculous.

4xlt

Gordy -- the family room is about 15' x 25' (earlier said 20' but I checked since). This room has 3 exterior walls with six foot tall casement windows all around, except where the fireplace is, plus 2 skylights. The previous owner added this room in about 1980. It is stick built while the rest of the house is brick. The breakfast room is 8' x 12'. It has 2 exterior walls with windows the whole way. The baseboards run in one shot around the family room through the breakfast room, making something of an L (see upper right rooms in floorplan attached). The linear feet of baseboard is about 75. The baseboard type is is the seemingly very common type. I've attached a pic that isn't my baseboard but which looks exactly like mine, down to the red plastic strip along the fins.

Gordy

you need to produce 334 btus a LF from the base board should be no problem with proper piping, water temps, and circulator.

4xlt

Here again is a photo of the install. I have other angles as well. This pic highlights the problem zone loop supply and return.

Rich_49

As far as the number of ignitions . You must have a buffer tank . This will act as hydraulic separation and will stop the short cycles you have been experiencing . Please give us the design heat loss for the smallest zone . We can then tell you how much volume you need and how to set it up .

Don_197

I was at Lochinvar factory training once a few years years ago.......and I got a chance to talk to the engineers and tech guys and I asked them.........."how do I want to set up these Knights to run.....once they are sized and piped correctly?" the answer I got and my goal from that period on was "the optimum is for the boiler to be running continuously at the lowest possible firing rate.......24 hours a day". I didn't really understand it at the time.....but I do now. A perfectly balanced and efficient system will only put as many btus into the system as the structure is losing. So.......cycling like that is costing you a ton of energy and wear and tear. You want LONG cycle times at the lowest possible temperatures.....with the boiler running at its lowest possible firing rate.

4xlt

Thanks Don and Rich.

Rich -- here is the only heat loss worksheet, marked and highlighted yellow to show the rooms involved in the small zone.

4xlt

"...the optimum is for the boiler to be running continuously..."

unfortunately ours is on/off, on/off, on/off.

75,000+ times in 3 years

Abracadabra

You need to up that zone's piping to 3/4" before you try chasing down other issues.

Tinman

No P/S piping, no air separator that I can see, grossly oversized mod con. Is the flue vent and combustion air piped to the outdoors in the same pressure zone? Great choices on the indirect and the boiler. It's sad that the contractor hasn't asked for help after 3 years. If they had, the problem would have been resolved by now.

Rich_49

That zone whether it has 3/4 , 1/2 or 1 piping is gonna short cycle the boiler quite possibly even at design . The issues are obvious with the information we now have . Please tell us what rooms are on what zones . This way we can determine smallest zone , need this to size vuffer tank correctly . Low end modulation for your machine is 40K hell with one zone you would short cycle into December the start again in mid March .
There is no real hydraulic separartion to speak of unless I am missing something .
' As for me suggesting a Grundfos , you have the wrong guy , never did it . ECM circs can be Delta T circs , these will insure an AWT for the circuit in question . Now , I must ask who performed this heat loss and does this house in fact have walls and if it does have walls , what do they do ? This heat loss looks as if the person doing the input had no idea what they were supposed to be doing , but for now we'll take it as right . Because when we determine that it is wrong your boiler becomes even more grossly oversized . Let's work on addressing the sins for now though .

Rich_49

40000 - 24468 x 60minute cycle divided by 10,000 (^Tx500) = 93.186 gallon buffer . If you want it running close to 100% of the time . 46.596 gallon for 30 minute cycles at design .

Tinman

Or, if your numbers change...