Troubleshooting My Propane Fired Radiant Heating System

[HillStreet]

Hi Everyone,

I have been spending a lot of time this winter troubleshooting my heating system, and I may just have found something that needed correcting. I am in a new house, moved in last March, and the propane boiler shows 1863 hours of run time and 3300 cycles. In my opinion, this is excessive. I ran the heat last year for a few weeks, and this season I have had it on since the end of November. Boiler does gas cook stove and dryer, as well as domestic HW, but the domestic HW shows 47 hours of run time for 11 months that we have been here.I burned about 1.3 tons of coal too during this time. I hired the licensed Master Plumber because he was a neighbor, and I thought being neighborly was the right thing to do. When I talked with him about this, and other issues, he shouted repeatedly "It's not my fault, I am only 27". I may or may not deal with him through the licensing board but I don't know if I have the energy to fight city hall. Anyway, follow my story please.

The house is single story, full basement, 28 x 54, 2 x 6 walls with fiberglass insulation in all the right places. The heating system is propane fired Burnham boiler, header tank, domestic hot water tank, and two heating zones-- bedrooms (3) and living room, dining room, and kitchen. The boiler and trim is located on one end of the house, and a main supply and return passes through the center of the basement. Two Uponor manifolds supply the under floor tubing attached to aluminum heat plates. The manifolds are 3 place for the bedroom end, and 5 place for the main house. Each zone and the system has a Taco 3 speed circulator. I adjusted flow on the manifolds, and increased the temp on the bedroom manifold.As I was troubleshooting the system, I kept logs of run hours, outside temp, sun or clouds, just to get all the data I could.

I discovered that the bedroom zone seemed to run about 90% of the time, and the main house about 10%. The floors in the bedroom were warm, while the main house floors were always cold. The bedroom thermostat was always struggling to maintain 69 degrees, while the main house thermostat pretty pyramid much always read 70 degrees even though it was set at 69.

Here is what I found: the bedroom zone would run and run, and the heat passed out of the bedrooms through the hallway, and heated the house thermostat, which was at the point where the bedroom zone ended and the house zone began. It was like running a heating system with a window open. Said another way: the bedroom zone heated the bedrooms, but the heat continued through the hallway into the open living room, passing the living room t-stat on the way. So, the t-stat for the living room was not calling for heat, and the bedroom zone just kept running, never really catching up.

Here is what I did: unhooked the bedroom thermostat and just left the living room thermostat running. I wired the control box to control both zones at once. All manifold positions are full open, and both zones are set at 110 degrees. I tested this earlier today and it heated the whole house to 72 (from 69 degrees) in about an hour with the outside temperature in the low teens. I then lit the coal stove because it is going sub zero tonight for the next few days.

I think I may have finally fixed the problem. I did a heat loss on the house and boiler is sized large enough. We oriented the house westerly/southerly and used big windows so the boiler never runs on sunny days. As for the plumber, he is toast with me, I cannot believe he said "It's not my fault, I am only 27". I actually feel sick every time I think of that. In my day you stood tall and corrected your mistakes. I have already non recommended him for several jobs. Oh, and I did not get a bargain because he is young, just the opposite, he wants to be a millionaire by 30. Now I won't hire anybody under 35. Everybody else on this job, and we built it during the winter, was terrific. I know this post is lengthy, but folks here will offer guidance about this system.

 

[mapper]

As you found out, thermostat location is critical in a zoned application. I have encountered this sort of a problem in the past in a couple of offices I worked in. In several cases it was very obvious to me that the location would cause problems, when I asked the HVAC contractor why they placed the thermostat where they did, the reply was that it was convenient for running the wiring and it was the easiest to do. I am not even close to being any sort of expert with heating systems but I do think that a bit of commen sense goes a long way. Relocating the thermostats so that they do not affect each other may be the solution if you still want a zoned system.
Another office I was in had some serious issues with the zoned system, my boss had an enclosed office while the rest of the area was open, the thermostat was located on the exterior wall of the enclosed office, on the side away from the cube farm. This caused the open area to be a bit cool to downright cold and the enclosed office was a sauna. After the HVAC contractor unsuccessfully tried a number of "fixes" including rerouting ducts, they called in their engineer. After looking the situation over he came up with a really simple solution; move the thermostat from its location on the outside of the office, seven feet above the floor to inside the office five feet above the floor. This fixed the problem, the enclosed office and the cube farm were both comfortable as long as the door was open, it was normally open only got closed for short periods for private conversations.

 

[HillStreet]

Thanks mapper. I was so focused on temperature and flow that I did not think about the thermostat other than it functioned or it didn't. I will leave it this way if it does in fact work long term. The different zones really is not a good idea because I just don't want to close doors. I really do hope this works because that is a lot of hours on the boiler for just a few months (and burning coal part time).

 

[TheMan419]

The thermostat is very commonly overlooked. In the office I work at we have 4 zones. In two of them the thermostat is in the wrong place. So one side of the zone is boiling hot in the winter and freezing in the summer. That is where my office is. So at least I can open the window to moderate the temperature.

In the house we used to live in we were having trouble with the AC kicking on at all times in the summer and the heat never coming on in the winter. We had a floor lamp right by the thermostat. Changed the bulb to a CFL and problem was solved.

As for your plumber, I would get someone out to look at the system. Tell you how it SHOULD have been done and what it will cost to fix. Most contractors have to be licensed and bonded. See if the bad plumber has a bond on file. If so you may be able to get some reimbursement there to fix the problem.

 

[fried1765]

The thermostat is very commonly overlooked. In the office I work at we have 4 zones. In two of them the thermostat is in the wrong place. So one side of the zone is boiling hot in the winter and freezing in the summer. That is where my office is. So at least I can open the window to moderate the temperature.

In the house we used to live in we were having trouble with the AC kicking on at all times in the summer and the heat never coming on in the winter. We had a floor lamp right by the thermostat. Changed the bulb to a CFL and problem was solved.

As for your plumber, I would get someone out to look at the system. Tell you how it SHOULD have been done and what it will cost to fix. Most contractors have to be licensed and bonded. See if the bad plumber has a bond on file. If so you may be able to get some reimbursement there to fix the problem.

A 27 year old "plumber" in (rural?) Maine with a "bond on file"?
Ya think?
Really?

 

[HillStreet]

His father is a long time plumber. No doubt he brought him up much too quick. As I found out later, kid has been in jail a number of times (I don't know why). Very irresponsible punk. Like I said, what bothers me most is that he denies all responsibility (I did not touch the plumbing), and says "I am only 27". I lived 2 lives before I turned 27. He will never earn my trust again.

I am just thinking that the licensing board takes care of themselves, not the sap that pays for their services.

 

[teejk]

Radiant heat is a constant balancing act especially when you add DHW (that probably is set for "priority"). We run a 6 zone system here (heat only)...basement (never on), master bedroom (never on), 1st floor living (always on), 1st floor master bath/powder room (always on), upstairs bedroom north and upstairs bedroom south (on when used). That is 6 pumps (Grundfos) running multiple manifolds (Rehau's). Do the math on that and see how that "balancing" is a PITA. We run a Weil McLain "ultra" (on demand...no storage). The concept is relatively new in the US and many "pros" are still learning. I have heard that maybe I should eliminate the outdoor sensor...it is the part that lets the boiler control how hot the boiler needs to be ("modulation"). Apparently the Weil McClain software engineers live near the equator and it works there...not so much in Wisconsin.

 

[CalG]

Radiant heat is a constant balancing act especially when you add DHW (that probably is set for "priority"). We run a 6 zone system here (heat only)...basement (never on), master bedroom (never on), 1st floor living (always on), 1st floor master bath/powder room (always on), upstairs bedroom north and upstairs bedroom south (on when used). That is 6 pumps (Grundfos) running multiple manifolds (Rehau's). Do the math on that and see how that "balancing" is a PITA. We run a Weil McLain "ultra" (on demand...no storage). The concept is relatively new in the US and many "pros" are still learning. I have heard that maybe I should eliminate the outdoor sensor...it is the part that lets the boiler control how hot the boiler needs to be ("modulation"). Apparently the Weil McClain software engineers live near the equator and it works there...not so much in Wisconsin.

It wrong to use an air temperature thermostat sensor to control a radiant floor heating system.

Sense the floor temperature. There is a learning curve to getting the floor temp right in order to be comfortable.
Think about it, when it's "cold", more heat is drawn from the radiant system. When it is "warm", less heat is removed.

SENSE THE FLOOR TEMP!

I've got radiant floor in two areas of the house, Floor temp thermostatic control works wonderfully. What a delight to put your feet on a warm floor regardless of the room temp. ;-)

 

[dadster4]

What is the BTU rating of the boiler? I have never heard of a boiler supplying heat to a cook stove and dryer, how are those appliances piped in?
Like many systems, yours seems to be overloaded with pumps for a home of your size, one pump for the floor zones and one for the DHW loop should be sufficient.
Why do you burn coal and in what type of heater/stove? I have installed many in-floor, under-floor, and floor warming systems and know that every system has it's unique properties and design variables. Most radiant systems with problems stem from an oversized boiler and an overly complicated component layout.

 

[HillStreet]

Thanks dadster4 for your reply. Oh, sorry to mislead about the cook stove and dryer, it is fed by propane, not the boiler, I simply misspoke.

I think you are right about the overly complicated component layout. The boiler feeds into a header which is supposed to prevent surges, and it seems to be a good thing. The boiler feeds a DHW super insulated tank, and that seems to be fine.

The boiler is a Burnham Alpine Condensing High Efficiency self vent boiler model ALP080BW rated Input 10 to 80 MBH and output 72MBH. THE DHW tank is HTP Superstore Ultra, and the mixing valves are Honeywell AM-1 series. Circulators are Taco 3-speed.

A circulator pushes (or pulls) water from the boiler through a 3/4 inch copper pipe running about 45 feet along the basement ceiling, then returns to the boiler. (This "loop" is essentially 2 parallel lines 6 inches apart, just to paint the picture). The two manifolds are tied into the supply and return lines, with a mixing valve and circulator at each manifold. I turned all circulators to number 1 setting (slow). The boiler feeds at about 180 degrees, and returns at about 160 degrees.

Again, I just disconnected the bedroom t-stat, and pigtailed both circulators to the t-stat zone that is in the living room. Trial run showed that this arrangement will work fine as it geared the house from 69 to 72 degrees in about an hour or so. Then I started the coal stove because we were going to sub zero at night and cold/windy/snowing for 4 or 5 days.

The coal stove is a DS Machine 160. It is freestanding in the basement, vented to a masonry chimney, and the heat just rises through an opening in the hallway. This stove never ran while I was troubleshooting the radiant system.

When this heating system started, I would casually listen for boiler/circulator running and realized that after the sun went down the boiler would run as much as 16 out of 24 hours, even if the outside temps were 35 degrees. Total run time now is 1863 hours---way too much for 4 months. It was running almost 100% of the time at night. Even at that, I stilled burned 1 ton of coal which kept the boiler quiet for a while.

 

[teejk]

It wrong to use an air temperature thermostat sensor to control a radiant floor heating system.

Sense the floor temperature. There is a learning curve to getting the floor temp right in order to be comfortable.
Think about it, when it's "cold", more heat is drawn from the radiant system. When it is "warm", less heat is removed.

SENSE THE FLOOR TEMP!

I've got radiant floor in two areas of the house, Floor temp thermostatic control works wonderfully. What a delight to put your feet on a warm floor regardless of the room temp. ;-)

Just to be clear...modern boilers now incorporate an outdoor sensor that determines whether the boiler is running full bore or somewhere less than that (what they call modulation). I understand it is some gov't mandate. Latest advice I got was as soon as the inspector signs off, disconnect that sensor in a way to trick the computer into thinking it is still there.

 

[dadster4]

Is the boiler controller capable of providing 180° water to the priority DHW loop and another temperature to the loops when the DHW loop is satisfied? Does the DHW loop have it's own circulator? Does the outdoor reset (lowers boiler water temp with an increase in outdoor temperature) only act upon the boiler when NOT in DHW mode?
Sorry for all the questions, but they are necessary to understand what the solution may be for a fix.

 

[sriddle1]

HillStreet,

Read thru your posting and was amazed at the 1863 and 3300 cycles, I too believe it is excessive. I built an ICF Home in 2013, the Walk-out Basement & 1st Floor footprints are 1,735 for a total of 3,470 sq.ft. The basement slab is 5 thick poured over the following: Stego Wrap 15-mil (over crushed stone) + Corning Formular 400 XPS + NIBCO 1/2 Barrier-Pex stapled to XPS then topped with Welded Wire Mesh laying directly on top. For my 1st floor I ran SlantFin Fine-line 30 connected by 1/2" WIRSBO UPONOR PEX. Like you I have (3) Zones, the Basement split into two (in-slab Pex) and the Main Floor (Slant Fins).

I also have a Modulating Boiler - Lochinvar KBN081 (80,000 Btu) but I went with a separate RHEEM RTGH-95DVP on demand water heater. My Boiler has the capability of setting up (3) Setpoint Temperatures, one for each zone. The Slab Zones are setpoint to 140 and the Slant Fin is feed 180. When I was designing the house I hired an HVAC "Expert" to perform a Load Analysis which pointed to a Boiler rating of 46,000 Btu Hr. I downloaded Slant Fin's simple calculating tool where each room is assessed and that tool indicated I needed a higher rated boiler in the 65,000 range so I settled on the Lochnivar 80K, over engineering but glad I did.

QUESTION: Just for the heck of it, have you gone thru a simple analysis to see if your Boiler was properly rated based on your Hot Water and Heating needs, assuming max demand on all of them. I only ask because I'm not familiar with BTU requirements for the Under Floor PEX snapped into the heat shields. I've been in homes where the same PEX approach was used, the sub flooring was 3/4 Plywood + 3/4 T&G Oak Flooring on-top, the heat hardly penetrated and it used allot of energy. Also you can't use the typical multi-colored carpet pads, they trap the heat so you need a dense pad that is designed for radiant heat. These issues really affect the efficiency of what I call between floor truss heating. I would hope there's a way to add those adjustments when deriving the proper BTUs needed to drive everything.

Next I have a TACO controller for the (2) Basement Zones and an overriding relay internal to the boiler that keeps the 1st floor as the top priority when more than one thermostat is calling. QUESTION: Do you have a similar controller or relays that prioritize which zone gets fed, and was it set-up properly. You have to be careful with overloading a Modular Boiler's throughput because it can seemingly run forever where multiple zones are not satisfied all at once. Old style cast-iron boilers can handle real loads but eat lots of energy too.

Lastly, reading your posting there is a simple solution if you want to relocate a Thermostat's location without worrying about wiring, I had to use this solution because I didn't run the right # of wires from a thermostat down to my Forced Air A/C (ooooppppsss). Purchased a Honeywell FocusPro TH6320R Wireless Thermostat that connects (wireless) to an interface unit you can install close to your boiler. Just some thoughts to share, not sure if it helps.

 

[teejk]

Is the boiler controller capable of providing 180° water to the priority DHW loop and another temperature to the loops when the DHW loop is satisfied? Does the DHW loop have it's own circulator? Does the outdoor reset (lowers boiler water temp with an increase in outdoor temperature) only act upon the boiler when NOT in DHW mode?
Sorry for all the questions, but they are necessary to understand what the solution may be for a fix.

Hi Dadster...I looked up the OP's boiler specs and they amazingly look much like my Weil McLain (condensing, modulating, outdoor sensor, etc.)! The OP is probably experiencing what happens when a computer takes over for what used to be a pretty simple system.

 

[HillStreet]

Dadster4,

Thanks for the questions. DHW has its own circulator. The boiler digital display shows a max 180 degrees wether it is supplying the DHW or heat loops. Mixing valves adjust the DHW coming out of the tank, as well as feeding the heat loops through the manifolds. I can only reset the outdoor temperature sensor, I don't think I can adjust the temp.

I do know that when the boiler comes on, wether heat loop or DHW, I watch the temp rise to 180 degrees, then it begins to fall from there with the circulators running. The display also shows the return temperature, which seems to be just below the max temperature, say about 160 degrees.

 

[HillStreet]

Thanks sriddle1,

The plumber allegedly did the heat loss with his supplier. I also did a heat loss a couple of months ago, plugging in all the factors. The house floors are 3/4 inch Advantech and 3/4 inch oak hardwood with tile in the bathrooms. Mixing valves are set at 110 degrees but that can be increased (my reading says it should be ok). The 3/4 inch hardwood over Advantech is actually ok to use according to my reading. Some area rugs but that seems ok.

I do think the issue was the t-stat arrangement I mentioned in my initial post. I will check it once this current cold snap is over because the coal stove is keeping us warm with zero propane. I will adjust temps and balance the system once I go back to propane.

I built this same house by the same methods years ago, but this house is 100 sf bigger. That house had a Baxi-Luna boiler with separate controls for heat loop and DHW. Two zones with circulators and that was it. That boiler ran for 15 minutes or so every few hours. I think I burned 400 gallons of propane all year, and burned a small wood stove on weekends mostly as I traveled during the week.

I also had a house with a 3section Weil McLain with slant fin 30. No trouble at all. I really regret trying to be "neighborly". He has caused me too much money, too much aggravation, and the little ******* never even said thank you.

 

[HillStreet]

Hi Dadster...I looked up the OP's boiler specs and they amazingly look much like my Weil McLain (condensing, modulating, outdoor sensor, etc.)! The OP is probably experiencing what happens when a computer takes over for what used to be a pretty simple system.

That is a fact. All I want to do is circulate water under my floor to efficiently heat the house. This "spaceship" I have downstairs is junk as far as I'm concerned.

I do have a Taco 4 place controller with DHW on priority. DHW shows 47 hours since new. I don't think that I can select different temperatures for the heat and domestic loops.

 

[dadster4]

I found a good manual to help change some operating parameters Table Of Contents - Alpine ALPB Installation, Operating And Service Instructions [Page 4]. Read through it a few times to get familiar with the terminology and how to adjust some settings, especially pages 83 on up. Some pictures or a drawing of the piping layout would help also. A few comments:
If the primary loop supply and return are separate or tied together at the end of the run would make a big difference how the system operated. The supply to each heating manifold should tee off the SUPPLY of the primary loop, into the zone pump, into the manifold, through the loops, back to the return manifold, into a closely-spaced tee (3" from the first tee in the SUPPLY of the primary loop). I don't know why a mixing valve is installed at the manifold, so follow the suggestions below before any physical changes to the system.
You are able to have different temps for DHW and heating loops. I am almost sure the heating loop temps should be lowered to maybe 150° vs 180° where they are set now. If your mixing valves are set to 110°, they have no way to reach this temp without cooler water available, set them to 140° (which is fine for under-floor heating). Condensing boilers are the most efficient when the return water temps are near the acceptable minimum (near 130°)...your controller will let you know when operating at this range.
The DHW loop should remain at 180°
The boiler may be over firing also. The controller has settings to change the maximum BTU output for heating and DHW, I wouldn't change these yet, but may be necessary to match output to required heat load for the house.
The regulator should probably be checked to verify that the input pressure to the boiler gas valve is correct.
All these changes can be set back to where you started if you keep a record of everything you do. It's usually best to try this before ripping things apart and repiping the system!
It's a lot to digest...and if it doesn't work "It's not my fault, I am only 58". :laughing:

 

[1stDeuce]

I'm busy learning about radiant floor heating as I prep to build a house this spring... We're planning to just do the basement floor at present, and we'll heat upstairs with wood or pellet stove. We won't be able to close off the basement from the upstairs, so I'm planning to use a floor temp sensor or two in the basement, rather than traditional thermostats.

From what I've read, the only real issue I see with your setup is that you're running a zoned system where you shouldn't be... Your "solution" is how it should have been set up from the beginning, since you don't want to close doors. Zones generally either need to be really large, or more or less sealed to work well. Your problem may be compounded by thermostats that don't quite agree on the temperature, biasing the bedroom zone to run all the time because it thought the temp was a few degrees cooler...

Bottom line: I don't think a zone setup is going to work well if you're not going to close doors to separate the zones.

I think also you keep saying "plumber" when you mean HVAC guy?? A plumber is generally NOT a HVAC expert, but is good at ensuring poo flows downhill, and the hot is on the left, cold on the right... If you hired a Plumber to install your heating system, you may be at least partially responsible for your troubles...

I'm 43, and I usually find that when I have problems, it usually IS my fault...

 

[dadster4]

1stDuece,
You can get by using a hot water heater for your basement floor to avoid the expense of a condensing boiler...but not the most efficient by any means. If I were to build my home from scratch I would have a condensing boiler provide all heat and DHW, bath floor warming, garage floor warming, guest house heat and hot water, hot tub, dog house, chicken coop...well you get the idea :thumbsup: