Help with poor install

paul8028081

Thank you in advance for your help, I'm looking to make changes to my series loop radiant heat system. A hack installed a LAARs Mascott II combi in our "as is" purchased house and I'm finally getting to fixing this issue.



Prompting me to look at the system 1.) is the boiler would cycle way too much 2.) even after running a heat loss calculation and verifying we have the appropriate amount of baseboards the system still struggles to heat the house 3.) Always hear the bubbles of air, especially by the circulator pumps no matter how much I purge the system



I "fixed" the cycling issue by having a LAARs certified installer come out and he adjusted some settings and in particular the Anti Short Cycle amount. But I'm still concerned about the overall design of the piping and system. I cannot find a plumber or heating company that is willing to work with me to design the layout or verify it's done correctly...I'm absolutely fine in letting an expert (and paying him/her to do it) but no one wants to!



The current system design matches the layout recommended by LAARs in their installation manual (copy is attached), which the exception of two areas.



1.) Piping on the supply manifold does not increase from 3/4" to 1 1/4" as is recommended. Instead it increases to 1" for the supply manifold, with an air scoop, expansion tank and two circulator pumps (taco 007).



2.) Piping on the return manifold is simply both zones meeting into a "T" with 3/4" pipe straight to the boiler. Again, LAAR's recommends 1 1/4" at this point back to the boiler.



So three things I want to do/verify.



1.) Obviously increasing both supply and return manifold to 1 1/4" Should help right?

2.) I plan on throwing away the air scoop and replacing it with a spirovent jr 1 1/4" air eliminator. Good choice?

3.) Are the Taco Circulators appropriate for my install? I have a simple 2 "zone" system with one for each floor of a two story house. They run on a loop around the perimeter, approx. 150ft of pipe each (house is 36'x24').





Thank you in advance for your expertise, advice and or questions!



Paul in CT

SWEI

More info

What is your calculated heat loss for a design day?



How many zones, how many feet of what kind of baseboard, and what pumps on the zones?



Is the outdoor temp sensor hooked up and is the boiler programmed to use it?

paul8028081

Re: More info

I don't have the outdoor temp sensor installed, I was redoing my siding...it's an easy enough to hook up. Will that have a significant effect?



Heat loss for the first floor is 22,037 btu/hr. The radiators are slant fin fine line 30's with 55 ft installed. Heat loss explorer tells me 50.9 is what's required for an outdoor design temp of 10 degrees (coastal CT). Never did a heat loss for the 2nd floor but that zone has been fine with reaching a high temp.



2 zones, each have a Taco 007 model, one zone for each floor of the house.

SWEI

Sizing and sizing

The spec sheet neglects to mention the minimum firing rate of the Mascot, but a bit of digging through the IOM revealed 20%, or roughly 24,000 BTU/hr of output capacity at minimum fire.   That's on the low end of acceptable for a 51k heat loss, and would work far better without zoning.



The bigger issues is that 55 feet of Fine/Line 30 is only capable of ~24,000 BTU/hr using 180ºF supply water and a 20ºF ∆T (ignoring the 15% "heating effect factor" the industry insists on adding to baseboard.)



I would double-check the heat loss calculation, paying attention to window U-values including coverings.  Once that is settled, and you have room-by-room numbers, you will probably need to increase your radiation capacity in order to properly heat the space.  You can either add additional baseboard, substitute higher output baseboard, or (the best option IMO) replace with modern plate radiators (e.g. Myson or Runtal.)   I would combine into a single zone and perhaps add TRVs, at least on a per-floor basis.

Rich_49

Bad & No Math

lots of all of it happened here I would presume .  Could you attach pictures of the boiler and near piping and also how the baseboard was run ?

  Do some rooms have multiple pieces of heat ?  How did you arrive at the heat loss number for the first floor ? Is there LOTS of GLASS on the first floor ?  Remember , the BEST WINDOW is a TERRIBLE WALL .

paul8028081

More info

I'm out of state until Sunday, I can post pics then. It's not a clean install at all, I've been working on tidying up some of the baseboard runs but they too are a mess. There's only four rooms on the first floor but they all have 2-3 units.



I have no idea what a good heat loss is for a 650 sqft floor, I'm assuming what I have is not good. I do have a fair amount of windows but the larger issue is a walkout basement which is unheated and uninsulated....that's a pellet stove idea for the future. I used slantfins heat loss explorer for the calculation.



I'm at a loss as what to do next...

SWEI

It's quite likely

that adding the basement into the existing system will make it short-cycle less and perhaps add very little to the monthly gas bills.  Time to begin at the beginning.

paul8028081

So my understanding....

So this is what I'm understanding:



1.) My baseboards are not enough for the heat loss...add expensive runtals or simular

2.) I don't have enough length off a "run" for the first floor zone to effectively run the LAARs Mascott II



Maybe I should just cut my losses, hire an HVAC for forced air and pipe zone 1 into an air handler!

SWEI

Room-by-room heat loss

Can you post your data and results?



Forced air would be my last choice here.  Radiant is soooooo much more comfortable.

paul8028081

Heat loss

Okay, thanks for your help. Here's my heat loss calc attached. Found a little error, the "alcove" was set to a design temp of 60, I changed that to 70.





I have the following amount of baseboards:



Living room 24

Dining Room 20

Kitchen 5

Alcove 6

Bathroom 3

Hallway 0

Total 58



Pics of the install to follow soon.

SWEI

Not perfect, but not all that bad

Did not realize that your 55 foot number was only for the first floor.



Can you post the numbers for the 2nd floor?

Rich_49

Fine Line 30

Could you please tell us in what room your series loop begins and ends ?   This could be very interesting . I have seen many systems sized perfect by the numbers but overlooking one important thing .  Every piece of heat removes energy and every piece after that is receiving a lower temp fluid which obviously effects its output . Also the imaginary 15% HEF .    And you said upstairs is good , correct ?

paul8028081

Re: Fine line 30

Okay here are some pics...lots o' pex! Notice the left side of the boiler does not have the 1 1/4" piping, I plan on replacing all of it.



In the diagram, the boiler is under the living room, the run begins and ends in the living room. The run begins left out of the boiler in the living room towards the dining room, then kitchen, alcove, back to the dining room, bath, then finally back in the living room.



I'll work on the heat loss for upstairs, but that zone was never really an issue...it can bring the heat up relatively well there. However if both zones are on at the same time it takes forever...my guess is that may be the lack of 1 1/4" pipe on both sides of the boiler for supply and return manifolds.

lza

spaghetti!

Paul,



Oh, man, that tangle of pex is cringe-worthy!  I guess it does add a nice palette of colors though. 



If you think you still have air in the system, I would check the auto air vent.  Sometimes they get clogged with bits of scale or junk.  In commercial environments, it is good piping practice to pipe air vents to a drain in 1/4 soft drawn or 1/4 to 1/2 copper tubing.  



The other possibility is a leak somewhere causing you to continually make up water. 



Spirovent Jr is what I have on my system. 



-lza

Rich_49

Thermostat

where is it located Paul ?  What are your plans for the basement ?

lza

step by step

Paul,



I think you are on the right track.  As a diy-homeowner tackling this project, it makes sense to clean up and correctly size the near piping before considering a sizeable investment in new baseboards.   Also, I would also put proper insulation of your new home at the top of the list. 



After cleaning up the near piping, I would strongly consider pipe insulation. 



-lza

paul8028081

cleaning and thermostat

Haha yes I have lots to clean up and to make it look nice. Thermostat is in the dining room so should be accurate. I'd like to finish one half of the basement one day....insulate etc.

paul8028081

step by step

I think the proper pipe sizing will definetly help. Lots of energy saving stuff already completed in the past year, Windows, doors, foam....it's been a mess!

Rich_49

Dining Room

If I am looking at this correctly there is 20 feet of radiation in the dining room which requires 11.5 . This on top of the fact that it is on the hottest part of the series loop may well be the problem .  The thermostat may be satisfying before enough heat can be supplied to the other rooms . I would eliminate that 4 footer on the interior wall to start with and employ a Delta T circ for the first floor zone , this will have the zone run long enough to satisfy other rooms and keep the temps to all baseboards closer to an average .  A good starting point for the money it will cost . 

paul8028081

That's the problem

Being that there is so many baseboards in the dining room, and the first floor is appropriately sized with baseboards, why does the system still struggle to reach 72 degrees?? It still does not get nice and toasty even in the dining room.



The system doesnt cycle on and off from the thermometer, the boiler itself cycles at times.

SWEI

Series loops

demand careful attention to sizing in each room or they suck.  Don't take this personally -- at least 90% of the ones we encounter suffer from improperly sized/balanced radiation.



One of the tricks we sometimes use is to split a loop into two shorter parallel loops, reducing both friction loss and underheating of the end emitters.

paul8028081

Thank you

Excellent! No offense taken, I appreciate all of the knowledge and help... so split zone 1 halfway up the loop with a T and have two "runs".



Any other issues you guys can think of?



Right now it's fix the loops...fix the pipe sizing for the mainfolds...