Anybody have experience with radiant heating?

[hot_pastrami]

Hi guys,

I've been fighting this problem for weeks, so I thought I'd see if anybody here had some experience and/or advice... the house I bought last May is semi-old (1978) and semi-rural. I am slowly recoving the place from it's previous state of ill-repair, but the one thing that I can't get working right is the radiant heating system.

I've had professionals come out twice now, and it's getting too expensive. Since I know nothing about radiant heating, I paid a guy to come clean and service the system when the weather started getting cold. A couple weeks later, it started failing to light most of the time. I replaced the pilot assembly, and that works fine now. Then, one of the section valves and the air bleeder went out, so I had a guy come out again to replace that stuff ($525 later... ouch).

So, all seemed well. But then, it started getting really cold outside, not just chilly. And the radiant heating can't keep up. This morning it was 50 degrees in the bedroom... brr. I have all the thermostats up around 72, and usually by mid-afternoon, a couple of the areas have reached that. But some, like the bedroom, never get above 60 or so.

The boiler seems fine... and in the boiler room if I touch the water lines that lead to the varous areas, they are almost too hot to touch. But if I go touch the wall panels in the rooms, they are mildly warm at best. Not having any experience with radiant heating, I don't know if they are as warm as they should be, but I'm almost positive they should be much warmer than they are.

My best guess is clogged pipes, but if I'm rigt, I have no idea how to resolve that. Another possibility is that the system is fine, but the poor state of the attic insulation is leaking all of our heat out faster than the system can warm things up. I'll call the serviceman again if I must, but I hope to avoid the expense if I can.

Anybody? Thanks.

Dude, this is not the advice you want, but..

Take $20, go buy a freaking space heater, and leave that son of a bitch on from about 6PM until whenever whoever gets up latest gets up.

Then, enjoy the new electricity bill.

[Griff]

Sorry HP as Schultze used to say, "I know Nah Thing!"

[russotto]

It's unlikely to be your insulation; a working radiant heat system can make the place HOT when it's really cold, insulation or no insulation. The pipes could be clogged (was the system filled with hard water?) or one or more of the other valves could have failed, or the thermostats could have failed. Or the pump could have failed.

As to how to resolve it... well, if the pipes are clogged, you've got to unclog them or replace them. Which usually requires access to them. Which you probably don't have. Which is one problem with radiant heat.

[hot_pastrami]

Originally posted by dave
Dude, this is not the advice you want, but..

Take $20, go buy a freaking space heater, and leave that son of a bitch on from about 6PM until whenever whoever gets up latest gets up.

Then, enjoy the new electricity bill.

I have a space heater that I turn on when I get up in the morning, so the wife won't have to deal with the cold room when she gets up an hour later. But yeah, it's too damn expensive to run for hours. My last electrical bill was up about $60 from usual... it'd be cheaper to have the service guy come out again than to run the thing all night.

I guess I ought to just call the service company again. Damn.

[hot_pastrami]

Originally posted by russotto
It's unlikely to be your insulation; a working radiant heat system can make the place HOT when it's really cold, insulation or no insulation. The pipes could be clogged (was the system filled with hard water?) or one or more of the other valves could have failed, or the thermostats could have failed. Or the pump could have failed.

As to how to resolve it... well, if the pipes are clogged, you've got to unclog them or replace them. Which usually requires access to them. Which you probably don't have. Which is one problem with radiant heat.

The reason I suspect clogged pipes is because the water is VERY hard here, and the previous owner got too lazy to fill the water softener with salt. When I bought the place I had to replace the dishwasher because it was almost a solid brick of calcium inside.

Fuck. Cleaning the pipes is probably a huge, involved, expensive process, but it's also unavoidable... we can't go all winter like this. It's a closed system, so introducing some kind of agent to break down the deposits would be difficult or impossible. If dismantling is necessary, I might as well replace all of the horizontal runs.

Shit. Maybe I ought to see if insurance would cover this, I just plain can't afford it otherwise.

[FileNotFound]

Originally posted by hot_pastrami
I don't know if they are as warm as they should be, but I'm almost positive they should be much warmer than they are.

Having had radiant heating in a house I used to live in back in Russia(as in place where it gets REALLY cold).

I can tell you that the pipes in the room should be so hot that just being NEAR them should make you uncomfortable and you won't be able to touch them without getting a light burn.


It's either the pump or the pipes. Nothing 'you' can do about that but you should be able to have somebody test the water pressure going in and out of the system. It 'should' be about the same.

I'm not an expert here and last time such a problem was discussed I was 13 but thats what I remember...

[zippyt]

2 words GAS LOGS !!!
We bought a set , logs , mantle , screen , etc....
I ran a line from our tank ( $100 worth of copper line and fittings , and $75 to rent the trencher for the day )

These logs will run out of the house if the blower is on .. Also Verry nice to be able to turn them on and off at will , as in on a cold morning i will turn them on and stand in front of them sipping coffie , AHHHHH FIRE GOOD !!!!!! No fire wood to find and get delivered or cut and stack , and no ashes to mess with and as i said if you get hot or tired of the heat just turn them off .

[BrianR]

Do you have shutoff valves in the system? Could one or more of those be partially closed? If not, then the likely culprit is mineral deposits in the pipes. You can replace most of the horizontal runs yourself, or put in radiant floor heating (I want this myself) and eliminate the vertical runs and make the floor warm to boot.

Brian
"DIYer extraordinaire"

[tw]

Originally posted by hot_pastrami
My best guess is clogged pipes, but if I'm rigt, I have no idea how to resolve that.

Start by following the pipes. Pipe comes out of furnace, loops at base of outside walls, and returns to furnace. Pipe returning the furnace should remain quite warm. If not, then assume a clog - which can be from many sources listed below.

Within less than a minute of when thermostat calls for heat, then pipes should start 'cracking' as heat immediately arrives. If not, then you know that loop is not working. But how many loops are there? Again you must learn this - powerful information for any homeowner that does not want to spend massive bucks on trivial problems.

Blockage can be a stuck valve, calcium restriction, sediment, air bubble, or even a bad impeller in the pump.

Sediment. Somewhere at the lowest end of a loop is a valve - probably with threading for a hose. Open that valve to flush sediments from the pipe - sampling the water into a bucket to see how cleans. It should be very clean. Just like they do in the spring to open fire hydrants. Flush those pipes maybe every five years.

Air bubble. No matter how many times those lines are bleed, air is still released from water. At highest point of each loop is usually an automatic air bleed valve. Especially if in high calcium water, then this valve might be clogged. Otherwise there is a mechanical bleed valve to empty air from the line. If pipe has an air bubble, then water pumps will never pump hot water through that line. Air bubbles are just as restrictive as sediment.

Having eliminated those two blockages, now the diagnosis and solution gets more complicated - too complex to discuss here without on-site examination. IOW that is what the professional is for - with you there to watch and learn.

[xoxoxoBruce]

Even if the water is *very* hard it only holds so much mineral. The washer used new water continuously but the heating system is a closed system. The only time new minerals are added is when the water is changed. I'm betting on air or something mechanical is blocking.
Start at the boiler and follow the pipe to see where it gets cold. Do you have several "loops" in the system? follow each "loop". The circulator is probably pumping water into the boiler so the other pipe would be the hot coming out of the boiler. Following that pipe, see how many times it branches off and that's how many "loops" you have.
Multiple thermostats? If so then you have "zones" and some sort of solenoids or valves to operate the "zones" independently. That would be a potential source of trouble.
If you shut the boiler down and put a hose on the drain, then open the makeup valve that adds water to the system and open the drain to get a good flow it should flush out sediment and more importantly a good flow will push out large pockets of air. Then shut the drain valve and let the system come up to the cold pressure marked on the boiler gage. It will probably be graduated in feet. At cold pressure it should be more feet on the gage than the highest point in the system is above the boiler, in feet.
Fire the boiler and when the temperature comes up the water will precipitate air which will have to be bled. The best way is to have someone stand by on the makeup valve and don't let the pressure drop while you follow the pipes and crack every bleeder to release the air. It *WILL* have to be done more than once.
You should be able to make the room hot with no insulation and the windows leaking, it's just more expensive.
You didn't mention what kind of heaters you have but you said "wall panels" so I would assume you have baseboard heat of either cast iron or more likelyn finned pipe surrounded by a sheet metal enclosure. Look inside the enclosure, particularly any place the pipe turns down, for air bleeders.
No, your insurance doesn't cover unless you got some kind of warranty when you bought the house.
Sleep with a hot woman or several dogs.

[hot_pastrami]

Well, I guess I should have provided more info...

There are four loops in the house, a north and a south for both floors. Each loop has an independent thermostat, but all thermostats are tested and working. Each of the section valves are also working, I had one replaced a couple weeks ago that was failing on me. When that was replaced, the whole system was flushed, so sediment shouldn't be an issue.

This system has an air bleeding device on the lower part of the piping, right next to the boiler. I asked the repair guy if we'd need to bleed the air out of a valve at the high point in the system, but he assured me that the little device will take all of the air from the lines... but then he also said that water softeners are useless and that I should buy special magnets to put on the pipes which "polarize the water's energy" and are "ten times better than a water softener," so maybe his advice isn't the best in the world. But on the other had, he said he almost the same setup in his house, so maybe his info is reliable. I don't know. The little thingy does appear to bleed a lot of air, you can see it bubbling out occasionally. Incidentally, it looks like it's not a closed water system, it has a contant, open connection from the house's water supply into the boiler.

The return path of the loop is hot to the touch in all sections except one, which is pretty warm, but not hot. The baseboards are the sheet-metal enclosed finned-pipe. They never make any noise or crackle when they are on... I presume that would happen due to heat expansion if they got as warm as they're supposed to.

So I guess my next best course of action is to see if I can find some high bleeder valves, and if present, open them up until water dribbles out. But if the return loop is warm and I've bled all the air out, the pump is probably OK, and the problem is most likely that there's enough calcium in the pipe that that it's effectively insulating the inside of the pipe, preventing the outer surface of the pipe isn't getting very hot.

Right? Or am I way off?

[xoxoxoBruce]

Two things. One the water maybe circulating too fast and have to be throttled back on the return pipe close to the boiler. Works like a thermostat in your car to slow the flow to allow the heat to transfer to the metal instead of flowing inside a insulating boundry layer of water inside the pipe. I still think there should be bleeds at the high points.
OK three things. The open supply to the boiler puzzles me. There may not be a traditional valve but there should at least be a thingy that works like a check valve and adds water as needed. It's an automatic feed and they always screw up in hard water.
If it is truly open, then when the heating system gets hot the water expands back into your domestic supply. Yuck. I'll try to find out more on that tomorrow. Look for bleeders.

[Archer]

Ok, I work in HVAC, small business. I'm not a tech!

First is bleeding the air, you can try to do it, and if you are resonably mechinically inclined, should be able to do it, though you may burn yourself in the process (just hot water, nothing to really worry about). There should be multiple bleader valves in the system. They should be near the radiators/fin tube, and may be behind the cowel someplace if it's fin tube.

Second, if you are still having trobles, get a professional. Keep in mind that just because someone "works" on a radiant heating system, does not mean they know what they are doing. See if you can find a company that specializes in boilers, even if it costs more.

Third, whatever that magnet nonsense is, don't even entertain the idea. I've seen boilers that have run for decades, with nothing but routine maintience (if that).

Fourth: Was the system running ok before the tech came out? I'm assuming that you may not know since you bought the house at the end of the last heating season.

Also a question . . . what kind of pipes are they? I was assuming blackpipe with old style radiators (cast iron or the like) It sounds from what you said that they are fin tube, and if that is the case, then it could be copper line. Is it? If it is copper, then you should not be getting popping and cracking.

If you're still having problems, I'll talk to my service manager tomorrow (11/26).

[xoxoxoBruce]

OK, I checked with my buddy the plumbing contractor and he assured me you have some sort of valve or possibly what's called a filltrol (which goes in the line) because the safety relief valve on the boiler is 30 PSI. I'm sure your domestic water is higher than that. He agreed that air or too fast flow are likely culprits.

Archer- I have finned copper baseboard and while it doesn't pop and crack, when it's coming up from fairly cool it does ring and ping. Not during normal cycling but if the heat is turned down like for the weekend when it's coming back up to normal operating temperture.