Help for complete amateur

Jamie Hall

Considering the construction of your radiant system, and the fact that you mention in your first post that the house isn't reaching temperature... that reducing the space heat set point limit is going to achieve much -- besides making you colder. With that radiant floor, about the most you can get out of it when all of it is working will be around 100,000 BTUh, which may not keep you warm anyway.

That said, do you have any convenient way of determining the temperature of the water returning from the system to the boiler? Your comment about the boiler cycling off -- again in your first post -- makes me wonder a little if you are even getting the full output of the boiler into the system. Knowing the return temperature would be helpful.

DZoro

HelpInAK said:

I spoke to the installer of the system. Heat transfer plates were not installed because “they were not cost effective,” and would have added several thousand to the cost,
But you just spent $1,600.00 in LP. That would have been much less with a proper installation of transfer plates, foil, ODR, and insulation.
The odr install is as simple as installing a thermostat, if not easier.
D

Voyager

I’m with ironman. That installer is either incompetent or a shyster or both. If the builder can’t get the HVAC contractor back there to make your system right, then I think your only options are to eat the cost of hiring your own HVAC contractor to correct the system or get an attorney involved.

A protracted legal battle may well cost more than just hiring your won HVAC company, but at least having an attorney send a letter is usually worth the $100 that will cost. If that doesn’t get a response, then it is tougher to decide how to proceed. If you can get a friendly judge who will award you legal fees, then it is worth it. However, if you don’t win, then you could be out thousands in legal fees in short order and still have a substandard heating system. Tough call, but probably worth at least a consultation with a good attorney.

Gordy

Was this person hired by you, or the GC of the build? Was there a home warranty?
Or were you the GC?
Courts will be very understanding of a homeowner who received underperforming installations from a general contractor. Especially if it is the GC’s choice who is used, and what is installed.

I think we need to help the OP determine if what is existing can be salvaged, and how.

Can you get pictures of the tubing installed under flooring?

Gordy

Let’s start with propane usage.

225 gallons a month equates to about 28.5k btus an hour on average. Probably a bit less since you said over two months.

You say you are heating about 2150 sf with the radiant. That’s works out to 13 btus a sf.

You did say below zero temps since November

You can’t control the fuel costs. You have to focus on usage.

Gordy

That being said an under floor “plated” install properly done, meaning using extruded plates, and properly insulated should carry the load.

Short cycling means the emitters are not shedding the btus being produced. This has a lot to do with the lack of plates to absorb the btus from the pex, and transfer them to the floor underside.

Gordy

Some side notes.

What is the room set point you are trying to hold?
What is it actually?
Are you setting back the thermostat?

Most of this is a preliminary assumption which is slightly skewed since you have non functioning loops, and insulation was not completely done for the period. Huge factors.

D107

As fellow HO, I feel bad for your predicament. While you have the attention of this site's knowledgeable and helpful techs, post some more photos wide angle view of your entire boiler and near piping. Take three or four from different angles. You will get valuable additional feedback that will help you add to the list of things that must be repaired. You might even engage someone on this site as a consultant via skype so you can record their comments as you walk around the boiler with your cell phone. There's likely to be a lot more things missing due to not being 'cost effective.' The question is do you really want the builder to try to fix what may be beyond his ability? Can a monetary deal be worked out so you can hire your own people?

HelpInAK

Oh boy I typed up a long response but it seems to have disappeared.
@Jamie Hall is the return water temp the same as inlet temp? The display is showing inlet temp 150-155 with boiler runner and outlet temp 166
@Gordy the builder hired the install company. Before I pursue any legal action I think I’d like to have a 3rd party experienced hvac guy come out and walk me through this mess. I’m not sure I would trust having the original installer back out here because according to him the system is installed just fine. If anyone knows a guy in the fairbanks, AK area I can hire for a quick consult I’m all ears!
The thermostat is set to 63, actual temps hover around 62-64 but the boiler short cycles it’s way back up when temp falls. I have since stopped setting back the thermostat after posting here.
I have a feeling the boiler will stop short cycling when the pipes are thawed, because it did stop short cycling for the garage when the frozen slab was thawed, but I am definitely concerned with the long term efficiency and gas use. Our energy rating report estimated 1100 gallons of LP use annually, which even then we thought was high. We are blowing past 500 gal in 2.5 months.

I’ve attached a couple more pics of the system in the garage as well as the staple job under floor.

Gordy

Is that that the set point you are happy with?
Or is that just what works, or trying to save fuel?
Are the joist bays insulated? If so how much?

Another question is this system using glycol?

Brewbeer

I have a feeling that this type of installation (plateless tube running at high temperatures) is not that uncommon in Alaska.

SuperJ

I don't like the idea of running PEX above 170f let alone over 200f.

If the installer doesn't want to do it, I'd recommend installing some heat spreaders and insulation in a small area, perhaps the bathroom, so you can appreciate the difference.

You might want to enable ramp and ensure you setpoint offsets are sufficiently wide to avoid short cycling. If short cycling continues to be a problem you could install a buffer tank, even a small buffer tank can really smooth out a modcon since the minfire is relatively low, heat spreaders will drastically increase the ability to remove the BTU's from the water, which will allow the boiler to run more consistently rather than immediately overheating the water. The pipes can't get rid of the heat fast enough right now.

Zman

To make what you have work properly, the following steps should be taken:

1. Remove insulation in joist bays, install heat transfer plates and reinstall insulation. Spray foam at exterior rim area would be a nice upgrade.
2. Install a radiant manifold in place of the undersized tee's in the crawl space. Since the tubing lengths are unknown, a balancing manifold would be a good idea.
3. Demo all of the 3/4" pex near boiler piping and rebuild with 1" copper. The layout looks mostly correct, the pipe is way undersized.
4. Eliminate the mixing valve on the garage loop and utilize the outdoor reset feature in the boiler controls. Install outdoor sensor.
5. From the sound of things, 30% glycol is needed to prevent freezing.
6. Repipe the domestic connections so the the T&P valve is as close to the boiler as possible.
7. Verify that boiler vent piping has been properly primed and glued. I pressure test would be ideal, especially since no primer is visible.

Who should pay for this?
The GC wanted to build as inexpensively as possible. He/she sees the heating system as a line item. They put it out to bid with little or no scope and went with the low bid. From the sounds of things some value engineering was done by the GC.

This may vary from state to state but the building code should require that the system can maintain an indoor temp of 70 degrees on design day. It would be very difficult to get a judge or jury to understand why your system is not heating correctly. You could spend a ton of money paying experts for opinions or you could just keep it simple. Prove that it won't maintain temp and then send them the bill for the corrections. The key will be documenting the deficiencies and giving the builder proper legal notice.

I would suggest purchasing a few temperature data loggers and recording your indoor temperatures. Send them certified letter after certified letter showing that your system cannot maintain temp. Once you have documented the deficiencies in accordance with your local statutes, I would tear the whole thing apart and redo it. Then take the builder to court for the costs. You should not have to deal with the heating contractor at all. You bought a product from the builder and that product is defective. The builder is required to make it right.

You can purchase these loggers and graph the indoor temps as evidence. https://www.onsetcomp.com/products/data-loggers/ux100-001?creative=178262173812&keyword=&matchtype=&network=g&device=c&gclid=Cj0KCQiAjszhBRDgARIsAH8KgvdDH5gBPw-hXTS7U7PjbSuPHEBv59bgJUbcQXnKwpzmart4OaiJ-R0aAizIEALw_wcB

Alan (California Radiant) Forbes

Wherever you live, there's an implied if not written rule that you have to be able to keep the house warm. Inspectors on one of my recent jobs required me to prove that the heating system we installed was able to heat the rooms to 68° on a cold day. The measurement was taken at 36" above the floor.

"Cost effective" is not a valid argument here.

SuperJ

Alan (California Radiant) Forbes said:

Wherever you live, there's an implied if not written rule that you have to be able to keep the house warm. Inspectors on one of my recent jobs required me to prove that the heating system we installed was able to heat the rooms to 68° on a cold day. The measurement was taken at 36" above the floor.

"Cost effective" is not a valid argument here.

To add to that, you can't run equipment materials beyond their capabilities. For PEX I think that probably means a max SWT of 180F. And for underfloor heat there is a variable max surface temperature depending on materials, or you risk damage (cosmetic or structural if you overheat a concrete slab). This is a long way of saying, turning the temp up to 200F is not an acceptable way to make the system "pass".

Adolfo2

I may have missed this but is this home part of a new development or a one-off? If one of many then what's going on with the neighbors heating system (strength in numbers)... are they happy or did the OP get the lemon?

HelpInAK

@gordy we are definitely not happy about keeping thermostat low, we are sacrificing to save fuel since we are using a whole lot more than we were told to expect. The joist bays are insulated with r-19 and the system is not outfitted with glycol.
@zman a checklist like that is exactly what I was looking for, thank you! Regarding proving the home won’t maintain temp - the home does maintain temp. I can set the thermostat to 70 and it will get there, i am keeping it lower to try and stop the bleeding from my bank account. $700 a month for winter heat in an environment with nearly 8 months of winter weather is not sustainable
@adolfo2 this home is part of a new development - 60+ lots but currently only 4 homes built and occupied. I’ve only talked to one neighbor and he is also using more than he was told to expect, although he isn’t too concerned with his use. According to him he is using around 40 gal a week with a home much larger than mine (we used 165 gal over the last 3 weeks). There really isn’t anyone else that I can talk to about their use because propane is not a widely used fuel source for home heating here - it is newly introduced with this builder.

On a side note, temps have dropped to -40 the last 24 hours and the boiler is having trouble maintaining flame and is frequently locking out (about 8 times now since yesterday) I had to take a vacation day from work so I can be here to reset it when it goes out. I was told by the fuel company that an underground propane tank wouldn’t run into this issue. This is a nightmare.

Jamie Hall

Is this an aboveground propane tank? They will have trouble. Lots of it. When the temperatures drop as low as you are getting. The boiling point of propane at atmospheric pressure is -43... at -40 or even -30, I am rather amazed that your boiler works at all.

Voyager

I would talk with an attorney before you make any changes to the system and then try to get the builder to pay. I did essentially this with work on my pickup many moons ago and one of the issues I had later was that I had not given the original garage the chance to correct their mistakes. The judge did not look kindly on that.

HelpInAK

@Jamie Hall it is an underground tank. According to the gas company, the ground should be maintaining around 35 degrees due to a high water table. They are sending someone out to take a look..

Zman

Propane has issues at those low temps. Underground should help. The issue may be in the regulator or line.

DZoro

At those temps don't let the tank go below 30%.
Who ever you get to look at it must have with them A) gas pressure gauges and , a combustion analyzer.
Anyone else is wasting your time and money.
How far away is the outside regulator?
It must be a minimum of 10' from the boiler.
Inside or on the side of the boiler should be the model number, what model do you have?

D

Gordy

So the plot thickens. You are able to maintain temp with the system as is. It is the usage that has an impact.

I would be monitoring the system pressure if you had frozen pex loops. Is the water feeder to the heating system open, or closed? If it’s always on I would close it to be assured the system is holding pressure. Also if it’s open, and there is a leak adding continuous makeup water is not going to be good on the boiler.

While @Zmans list is indeed a good one which will reduce water temps, and help efficiency with the boiler getting in condensing range. Right now it’s efficiency is mid 80s with those return temps. Getting return temps below 130 picks up efficiency points getting it up in the 90’s.

The problem becomes it’s not really a system that doesn’t work....well except for lock outs now.

The problem is you were told a certain fuel usage to expect by design, and you are above that. This turns into a complex problem as in weather, system design not delivering promised efficiency.

We roughly know based on what you told us an average btu per sf. Which will be higher as temps drop, and lower on warmer days. An average of 28500 btus an hour. What size is the Nobel boiler? I’ll bet it’s lowest modulation isn’t much lower than the 28k.

The estimated usage has to be based on the envelopes btu requirement at a given indoor temp. It also has to be based on a given outdoor design temp, and average degree days for the location.

If you are using a higher indoor temp, and or degree days are higher than normal then the argument becomes weak.

Also an estimated fuel usage will be based on units used not cost of the units used.

Ironman

I'm going from a very long ago memory on this, so the validity needs to be confirmed, but I think there's a temperature limitation for the glue used in the top and bottom cords of your TJI's. Stapling the tubing to them carrying that hot of water may cause delamination.
One of you really smart guys, please confirm if this is true.

Gordy

Ironman said:

I'm going from a very long ago memory on this, so the validity needs to be confirmed, but I think there's a temperature limitation for the glue used in the top and bottom cords of your TJI's. Stapling the tubing to them carrying that hot of water may cause delamination.
One of you really smart guys, please confirm if this is true.

Bob everything I have read for testing suggest nothing relevant until you approach ignition points. There are many different types of adhesives used in various laminated would products that must endure moisture, temperature, and of course maintain strength in various loading. Tensile, and shear mainly.

Most studies are focused on fire. Which as you know has been a hot topic for firefighters entering these types of construction using TJI,BCI,and other laminated wood products.

That type of construction using these components is consumed by fire 8 times faster than conventional dimensional lumber........

https://www.news4jax.com/news/local/newer-homes-can-burn-8-times-faster-than-older-homes?__vfz=medium=sharebar


Sorry I didn’t mean to derail the thread, but the opportunity arises to learn something relevant.

DZoro

The choice of installing the tubing in that position is so wrong, but so is everything else that has been done to this poor house and family.
D

Jamie Hall

I think you are right, Bob, but I can't find my references which are around here somewhere... I'll keep looking.

mikeg2015

At 166F, assume return water is maybe 150F, your effeceiny even at 20% firing rate is probably 86%. It’s not even condensing.

Really good radiant designs can use 110F water or lower most of the winter with a well insulated and tight house. With return temps around 85-90F, and you get 95-97% efficiency at low firing rates.

HelpInAK

@DZoro the model is the noble nkc-199. The tank and regulator are about 20ft away from the boiler outside the garage. The gas rep came out and believes the lockouts were due to a moisture issue. He worked some magic outside and thinks he solved it - if it happens again he’ll come back out and remove the regulator. No issues since he left.
@gordy the feeder into the frozen loops is open. I’m hoping we can start the thawing process today, should I still close it?

The project manager arrived and confirmed insulation was missed in the dining room crawlspace. We’ll be given another $500 refund to help defray the propane cost (after an initial 500 for the skipped dining room ceiling insulation). Insulators have already arrived and completed the job. I brought up and questioned the lack of heat plate use with the pex pipes. He honestly seemed unfamiliar with what that even was, and said the current setup was up to code and is the setup he has always seen. Before going any further into discussion with the setup (I will definitely ask to have the ODR set) we decided to table it and focus on fixing the immediate freeze issue and see how that affects the short cycling and usage.

Honestly I am ok with a less than optimal setup as long as I get something close to the usage I was told to expect. I’m not sure I have the stomach for a long, drawn out legal battle, and I have to leverage any additional investment with the fact that I’m not expecting to own this house longer than about 5 years (I’m active military).

I know I’m still scratching the surface on how this all works. The knowledge I’ve gained here is absolutely invaluable as a new homeowner so thanks again.

@gordy I’m definitely trying to be careful regarding my expectations of our usage vs the energy rater’s estimate. I’m definitely not basing it on cost of units used (estimate used $4 per gal, I’m paying much closer to 3) I’m only bringing up the total $ spent thus far to demonstrate the urgency I’m facing. Also the estimate was based on a 70 degree thermostat setting, so I felt confident we could beat the number considering we keep ours below that.

Voyager

Ironman said:

I'm going from a very long ago memory on this, so the validity needs to be confirmed, but I think there's a temperature limitation for the glue used in the top and bottom cords of your TJI's. Stapling the tubing to them carrying that hot of water may cause delamination.
One of you really smart guys, please confirm if this is true.

Epoxy glues are known for softening at higher temperatures, but even most modern epoxies will easily handle 250 degrees F so I don’t think any hydronic system is cause for concern. And I don’t think epoxy glues are used for most engineered lumber.

Voyager

A lot of things can meet code and be far less than ideal. Most building codes are concerned with safety first and foremost. Things like energy efficiency are way down the priority list.

HelpInAK

Also I’d like to note that I told the project manager that I had joined an online hvac group for advice from other professionals, and that that is basis of where my design concerns are coming from. Unexpectedly, the answer given was that it’s important to remember that the way things are done in Alaska are often very different than the way they are done in the lower 48 (which I’ve learned is absolutely true in my 4 years here so far)
@MikeG is it possible that the high return temp is in large fact due to the dining room loop being inoperable? Once that is thawed should I expect that return temp to lower? It would seem to me that simply lowering the output temp, to say 150, would have the return temp lower accordingly and improve efficiency, knowing that the lower output will increase heating time, which we can handle considering I’m no longer doing any thermostat set backs. Is it not that simple?

Zman

There are lot's of plateless staple up systems from the 90's in my area. With high water temps, they seem to be able to heat approx 15 btu/ft. I have never seen damage to I joists or plywood, I have also never seen them attached to joists like that. High humidity combined with warm air will destroy I joists quickly.

Voyager

Zman said:

There are lot's of plateless staple up systems from the 90's in my area. With high water temps, they seem to be able to h+eat approx 15 btu/ft. I have never seen damage to I joists or plywood, I have also never seen them attached to joists like that. High humidity combined with warm air will destroy I joists quickly.

Are they in an area that sees -40 in the winter? I think platelets systems would work fine if you are in a well insulated home with outside temps at or above 10 most of the winter. I think in Alaska it should be a crime to omit the conducting plates.

Zman

I am not saying that I think it is a good idea. I can say that there are many million dollar mountain homes in Zone 7 that heat with high temp plateless radiant Many have poor insulating details as well.
I don't doubt that many Alaskan homes are heated this way.

Voyager

I hope those million dollar homes didn’t waste money on a modcon expecting 90+% efficiency.

Gordy

In this case it appears to be working. We don’t know the insulation details of the envelope. He’s able to hold desired set point with lack of insulation, and non functional loops. With high water temps yes, but as we all know staple up requires such especially in the well below zero region.

So while I don’t agree with the design being the most efficient as we all strive for, and that’s the lowest possible water temperature to meet the load with the least amount of pumping. This all to gain efficiency at the boiler. To do so you need a conductive emitter “plates”, and in new construction nothing beats an over the top plated design for lowest possible AWT.

What the OP is realistically facing is he was uneducated in what he was getting at no fault of himself. Prey of a GC, and a installer who doesn’t put a best design first. that does it all the time, and most don’t know any different because their house heats.

So the argument of the design is out the window with the GC, and installer so long as it meets the load, and code is even on their side. By the way I would look into that code as it could be a bluff.......

Gordy

As far as the heating of the laminated components you won’t find anything in that temperature range that results in significant degradation of strength. However as @Zman points out if moisture isn’t kept in check the two together is definitely a recipe for failure. Not the glue, but the wood. A video Rich Mcgrath posted in another thread shows just how damaging moisture is to SIP panels in roofing systems with out proper design.

hot_rod

What size Nobel, a 110,000?

HelpInAK

@hot rod_7 199000 BTU noble