The AM Forum

Hola,

I wonder if anyone has an idea for a commercial device or maybe a ready to go 555 timer circuit design that will give me a 5 min ON every 2 hours or so?

I've had the coal stove running 24/7 and haven't had to turn on the oil-fired furnace for 3 weeks now. However, I realized that the copper baseboard heating pipes are not getting hot water and may freeze. Last night it hit 8 degrees F here and I turned the furnace on for circulation. There was a section of the copper pipes that did not flow right away - evidently had ice inside. So I manually run the furnace circulator every few hours now... whew!

 I think maybe a 555 that does a 5 minute duty cycle pulse with a 2 hour base could drive a relay?  I was hoping there is a circuit out there so I don't have to do R&D.  

I looked at the day/night digital lighting timers and the descriptions are not clear enuff to figure if they can do what I need.   I want to turn it on and see a 5 minute ON every 2 hours or so, continuously.

Ideas and circuits are appreciated.

Thanks.


T

Don't you have glycol in your hotwater system?

Hmmm... don't know. The furnace was recently installed new a year ago. Is this a standard thing?  I shud call the guy and axe him.


BTW, the furnace does come on regularly now to heat the water for washing - but the circulators for the baseboard heat do not come on at the same time beacuse I have the thermostats turned down.. Maybe there is a way to allow this to occur at the same time? There is a digital control box on the furnace...

T

I think some of the newer systems use a closed circuit with a coil inside the boiler to heat the baseboards or a slab, most likely filled with some sort of glycol substance. Older systems like the one I had in the VT house simply circulate the boiler water through the radiators and back to the boiler. They auto-fill from the water line to compensate for losses through the over pressure valve and so on.

Your timer/cycling question is an interesting one, Tom. Never had that issue since the old house wasn't terribly tight and even with the wood stove cranking, it would still kick on regularly. There's a control sensor (Aqua-stat?) that allows you to set the high and low cut off temps for the boiler itself kicking on to maintain temp, wonder if that system could be adapted to the circulating system itself? I became quite fluent in the use and setting of that little beasty on my circa 1991 system when fuel oil prices got up around $4/gallon a few years back and I wanted to optimize the settings. Turns out it could've been set down lower long before I did it, since the internal hot water coil had been replaced by an outboard water tank. It was maintaining the boiler at an unnecessarily high temp in case someone used the hot water.  ::)

I talked to the installer who said there is no glycol in the heating system. It would cost about $300 to fill, unless I bought it and did it myself.  

He also said that pipes can freeze in 30 minutes when super cold. They had cases where a working system had frozen, never mind my intermittent coal aided system.

So looks like I may have to go with a  5 minute on every 30 minutes when it gets cold.


T

I've used sprinkler timers for a lot of timing applications. Lots of them have very flexible programming options. With a little trickery, you could even use some kind of N/C thermal switch with the rain sensor input to have it switch on (N/O on input) when it gets below a certain temperature.

And they are relatively cheap.  ;D

Tom,
Turn off the system power.
It is pretty easy to do. Turn off auto fill and drain out some water. Then go on the second floor and pour some glycol into a register. Take a bleeder off and get a couple fittings to interface to a funnel. I would think the system has about 15 gallons so you just have to decide how much you want to use.
Then close everything up turn the auto fill back on and bleed the system.
Make sure you drain out a bit more than you plan to pour in.

Hej!

I would say that running the burner for a short period of time may cause trouble in the long run due to condensation, if you let it run longer then you will not have that problem.
And, it is probably more economical to let it run 15-20 minutes/day?

Condensed water + sulfur (comes froom the oil) is probably not good?  

Another option is a second thermostat in parallel set to a low temperature located in the basement.

Tom,

Is it possible to circulate the water without running the boiler? If that can be done a few of the radiators could be used in reverse. A fan or two pushing warm room air over a radiator to keep the water above freezing. Just moving the water might be enough. Add a fan if you like.

Mike

Had our hot water heating system winterized at our place in Michigan before we left for the winter.  The cost of anti-freeze was in the neighborhood of $300.  But we'll not need to do that again next year and onward.  Plumber told me that my system is in very good condition and adjustment, thus little or no water will be added, so shouldn't need to test the antifreeze for some time down the road. 

Tom,

As SM6OID mentioned, condensation is a real issue with the boilers of oil furnaces when they are allowed to cool down enough for it to form. It is a mess to clean up once it starts!

Rob

furnace makes hot water so cycle isn't an issue. Tom how about some insulation in the basement around the sills. It will make a big difference the basement temp. Usually only a couple inches of wood to the outside in each cavity just above the foundation.

You might be on a good thought to have a timer to give a closure to the thermostats in question to call for heat every two hours just to move the water in your two minute window.
Or a closure right at the circulating pumps. How many zones do you have?
I think it takes much longer for the cold to penetrate and start freezing water. Pipes exposed to the direct cold?. How's about heating tape on any exposed pipes?
Are there unheated areas that are getting into the 30's?
When we heat with the pellets the unheated areas in our house only go down to 55 on our single digit nights.
I realize your cold is more severe than Western Pa.
FRED

TOM I saw your post about 30 minutes to freeze a WORKING system,,,you have serious cold there bro!!

Lease out space on your towers to a few FMs and vent their tx shack into your place.

Yes, Frank, the hot water cycle comes on often enuff so that the boiler is warm/hot all the time. I don't see condensation an issue because of that.

The problem is there is an exposed 1' long piece of heating copper pipe that runs under the house to a house section that has no basement. It is an inaccessible crawl space, so that pipe must have some hot water or glycol run thru it. Can't get at it for heat tape.  That was the section that I found clogged with ice this morning when I turned on the circulator and found the water hot going in, but cold on the output for a minute. It then cleaned out and is normal now.

It's a two zone system and there are thermostat terminals I can key closed right on the furnace controller. So if I can find a good timer circuit I will put a pair of contacts there to activate the circulator. The boiler appears warm most of the time and many times the circulator pushes hot water without the boiler coming on - at least enuff to keep the pipes hot.

Frank, maybe I'll pay you to come over and add some glycol..  ;D There's no fillers upstairs - all work must be done at the furnace valves, etc. Can I use standard car antifreeze and do a 50-50 mix? Maybe with that and the timer it will cheaper and be OK. lt might  work in conjnuction with the timer circuit to be effective against freezing.

T

Auto antifreeze is likely a bad idea.  The stuff you use should be safe for human consumption - not the correct terminology but that gets the point across.   

Why?   Your domestic hot water coil is sitting in the middle of the heating water. 

Typically a failure (leak in the domestic heating coil) will cause the heating system a problem because the pressure in the heating side is only 10 or 12 PSI (there's a pressure reducer on the heating water feed) vs the domestic water side at 40 or 50 or more psi.   

However, if you get a leak and Murphy is really lurking, you don't want to be sipping auto antifreeze.

Good Luck!    73, Bill  N2BC

Good thinking on the antifreeze risks, Bill.   Yes, if the dog got some, it doesn't take much.

I decided to buy one of these digital light timers. Not bad for $16. It will take detailed programming up to 120 entries, so this should handle a long list of on/off commands to keep the circulator going every hour or so, depending on outside temperature.

It will key a 120V relay and then key the two circulator zones for 5 minutes each cycle.

I'll hold off on the glycol for now. I think running the circulator at least every hour will keep the pipes safe. I mean, WTF.


T

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Wow. There's a lot to sort out here. First off, do yourself a favor and try to keep the antifreeze out of the system. Propylene glycol (pink stuff) should only be used where there is no other choice to avoid pipe freeze up. It'll harden up any seals it comes in contact with like flo-checks, domestic coil gaskets, circ shaft seals, etc... To get the proper mix into a system, the preferred method is two hoses, a pump, and a bucket. The reason they want 3 bills to do it is because it takes about 2 hours to do it right, and a 5gal bucket of NoFreeze is about $75.

I think jogging the circulator is a bad idea. Hot water freezes faster than cold water. I had a call a while back in which I was bleeding out a system that had one leg of copper in an attic. I knew about it, so in the time it took me to go out to the truck and grab a bucket of the crap and come back in, that pipe froze. We're talking not even 10 minutes and the returns were coming back hot before I went outside. It was down around 5° when this happened. The fix was to put a 500w halogen on it, rebleed the zone and get some NoFreeze into the system. In your case, jogging the circ would just heat the pipe momentarily and not provide any heat to the surrounding area to keep things warm during the off cycle.   

The better idea would be to determine exactly where the freeze up happened and address the problem at the cause. Is the frozen pipe in the basement? The most common freeze up point in basement piping is where the pipe's run near the rim joist and stub up for each radiator. Make sure the pockets above the sill plate are all filled in with insulation. In other words, if it's a cold air infiltration problem causing the pipe to freeze, then I would address it there.

All that said, it's impossible for me to know what you have going on out there. Installations vary widely and it has nothing at all to do with the house itself. I've seen the nicest most expensive houses have the most embarrassing hack job installs, and I've seen regular every day homes have the cleanest nicest installs ever. Every system is different, and it totally depends on how your system is set up and planned out if crutches like antifreeze and heat tape are needed. I say try to figure out where it froze and see if there's a way to correct it. Once those options are exhausted, then put the pink bile of death into the system.

J     

hey Jared,
I think I read that Tom has one(?) inaccessible area that is prone to freezing.
And right on to hot water freezing faster......it was a school homework assignment I did with a high schooler. Unbelievable!
I was thinking for Tom to keep both systems on and they assist each other.
sorry if this is hijacking the thread::::::::
I have tri-level house. And I need to heat the upper floors with pellet stove. 73 is much nicer than  68 degrees,,,,,,,,,ya I'm spoilt.
In the past I would shut the entire heating plant off and only heat with pellets. The family room would be 55 degrees. And turning on expensive space heaters to make it comfortable doesn't work. The furniture and walls are still cold and we are never comfortable. By keeping the main heat on, hopefully keeps the lower levels comfy and will "assist" the pellets.
I ordered a wireless thermostat. ( A good Honewell unit) I'll install it in this "family Room" and will keep the main heat system on at 66 degrees,,,,,close all the supply vents UPSTAIRS except my son's room,,,coz it gets a little cool in his room, when we heat with pellets, and see what happens this season. I'm afraid to see the gas bill for the last month.
I have been hanging those digital thermometers all over the place the last two weeks and I think I have it figgered out
FRED

Hi Fred. What is your system exactly. Is it a straight air furnace, or hydroair fed with a boiler? Reason I'm asking is because if it's a straight air furnace, then closing off supplies (more than one or two anyway) will cause the furnace to cycle on the high limit. The lack of airflow overheats the heat exchanger and causes the high limit to cycle the burner off. This will usually crack the heat exch in a very short time ruining the furnace and introducing a not so nice helping of CO into the living area. Not a good thing. 

Jared, you jumped in here right on cue. I was going to ask where our "Forum Resident HV/AC guy" was hiding........I mean operating.  ;)

Hiya. I try to help out anyway I can. I know that there are some of the best minds on this board and I can pop a radio related question out there and they jump right on it and straighten me out. So my contribution to the hive is my 20+ years experience dealing with hvac/r system design and failure analysis/repair.   

Thanks for the info, Jared.

Yes, as Fred mentioned, I have a 1' length of copper pipe that goes under an inaccessible crawl space outside (in cold air) before it enters the house addition. No way to get at it for insulation. It has been that way for 25 years with no problems when the furnace ran itself without the coal stove.

But now, the coal stove heats the whole house quite well and except for hotwater, the furnace has no need to come on.  

I'm surprised that the hot water can freeze so quickly. (10 minutes)

I will stay away from the glycol.

The problem is that it is difficult to set the furnace thermostat to any workable back-up level because the coal stove does not have a stable temp range as you know. The coal stove would have to be watched too closely as it goes thru its burn cycle.

Maybe I can drill some holes and snake some insulation around the exposed copper pipe. But I want to try the jog circulator idea too - even if I have to auto-turn it on every 15 minutes during the real cold days.  

T

Jared,  We have to put a glycol based fluid in all boiler systems in Alaska......You made mention of the glycol being tough on some of the components and seals.....Doesn't seem to be a problem for us...The boiler runs year round in most areas....just not as often in the summer month......Steve

Tom,
You would be amazed with the amount of heat you can get from a light bulb.
My two 100 watt bulbs in series will keep the water meter area about 70 when the rest of the basement is 42. If you could get some heat in that area then the problem goes away. I assume this is under the shack area of the house. If you need to get through concrete rent a hilti drill with a 1/2 inch bit.
It should go through a wall in a minute or so. Then blast yourself an access hole.
I worked on a 1811 house that was moved and had an addition added. It had the same problems. We got under it and added insulation around the outside wall.
That was the easy part. Then we had to pour pads and stuff a 16 foot carrier beam down the center to hold up the floor up. Some clown had used 2X8 on a 14 foot span with hardwood floors parallel to the 2X8s. all this through a basement sized window hole.

Running the circulators on a timer is probably only a stop-gap measure. The outside air will freeze the pipes the next time you get a sudden drop.

There are two ways to go here:

• Shut off and drain the pipes that aren't being heated. You can put a couple of shutoff valves in the zone that's prone to freezing, and simply drain it, provided that your coal stove is able to heat those areas past your family's "point of pain"  ;)
• Install an in-line temperature sensor in the pipe, and use it to control the circulator motor. If your boiler is being used for hot water, this may be the only protection you need, although I'd recommend including a timer that fires up the boiler if the inline sensor doesn't detect heat within a few minutes. Sensors are not cheap, and you'd have to place it at the point in the pipe where freezing is most likely, so I'd go with method 1 to get through the winter unless you're willing to run the pumps 24/7, and when the warm weather is back, design a permanent solution.

The long term solution is to insulate or move the pipes that are prone to freezing, assuming that you'll keep the existing radiators, but before you do, it's a good idea to step back and think about other ways to accomplish the goal.

• There are a lot of "single room" heaters available, and removing or abandoning the pipes that freeze may be your best long-term choice. Newer models will rival or exceed the efficiency of a central heating plant, and are cheap compared to the cost of a single freezing incident repair.
• The offending pipe might be accessible from underneath, or via a vent window, so you may be able to insulate it after all. Don't forget spray-in foam and other insulations that can be delivered via small openings.

HTH.

Bill, W1AC

I got another dumb idea. Find the source and return pipes and connect it to a the secondary of a filament transformer with good solid conductors. Pump a couple hundred amps down the section of pipe to keep it warm. You could use a thermostat and a relay control the primary of the transformer. I seem to rember a homebrew transformer on a variac core that could be pressed into service.

Bill and Frank -

Thanks for some really good ideas!

Bill, I did consider blowing insulation under the room. There is a couple small windows for access, but painful. But it would block the piping underneath. I just looked and realized that the connection between the two baseboard radiators is connected by a length of about 20' of copper pipe that is UNDER this room in the cold!  Gads, no wonder I had a problem.   Frank, yes, this is the ham shack room without a cellar below it. Your idea about putting a couple hundred amps thru it sounds appealing. At 6v thats about 1200w or less on a Variac.  It will put some power thru the rest of the circuit to the furnace, too. That seems to be the only viable idea unless I blow in insulation, and even then, I still need some circulator flow periodically.  Do you see a problem or safety hazard with this idea, Bill?

What I don't understand is this:  If the hot water can freeze in 10 minutes, how did I get away all these years running the normal furnace through this pipe when the furnace would shut off for 30 minutes at times in the deep cold?  At least with the circulator jog idea I will have hot water circulating every 15 mins or whenever. Of course, the circulator runs independently as long as the water is hot enuff - if not, the furnace comes on to heat it up and then shuts off.

T

Why not crank down the zone valves for that area to barely open and run the circulator continuously on the super cold nights? The water flow will be minimal and the furnace will still come on when needed to keep warm water flowing in the system.

I ran a wood stove for 12 years at a prior home and had to get creative with the furnace system to keep pipes from freezing.

Hi Steve. I have wondered about that before. It makes me wonder about the variables involved when comparing two applications in two different geographical locations. The seepage I find on some systems always seems to be in the same locations like flo-chek seals, drain/bleeder valve packing's, circ flange gaskets and so forth. These parts always seem to show the same pink powdery crud in the same places. I wonder if it might be because in my area, the zones are turned off of half of the year and the cooled off parts start seeping boiler water. I swapped out a Taco zone valve last week that was leaking around the plunger shaft seal and the inside of it was covered with pink flaky debris.

J

LoL, that's how we used to thaw frozen water mains. I would drop a copper pipe down into the curb box so it touches the street valve and run 2ga up to the house and into the basement and put the clamp on the piping before the meter. I'd have the cust open up a faucet and i'd fire up the Lincoln SA-200 (aka Stinkin Lincoln because it smoked like an SOB). 30 seconds on the pipe at 175A and the water would start moving again.

Anybody that stops by the garage and see's my machine is like "WTF is wrong here?" It has 40ft of triple 'ought' on one side and 250ft on the other side.   

Tom,
Check out Home Depot. They have a new blow in insulation that has some borax in it the keep the varmits out. They also rent the machine to blow it in.
I was talking to a contractor in the store a few weeks ago and he said it is great. He said new houses people have been going to R48 overhead and this new stuff is a lot easier than fiberglass batts.
Man I bet that tile floor is freezing in the morning.

I'll certainly check it out.

Yes, this floor/room is cold in the winter. Plus I suck in air from outside for the big rig blowers... brrr.

I guess the disadvantage is once it's done, there's no access underneath anymore.  If a pipe broke I'd have to run in above floor.

T

Do you know that most baseboards are set up so you can run the return line just above the fins of the radiator. It just takes a special clip that you can make or buy to hang the copper pipe. I did that in my solar room since we are sitting on concrete and rock. The radiant heat wasn't quite enough to heat the room plus the kitchen so I added baseboards with return lines above the fins. This might be a way you could modify the system to eliminate the pipe under the floor. Route it back to the basement where you could make the splice.

We use glycol both hot and cold in alot of our systems at work. Some of its tempered, some of its -20° and we have some that runs 50°C depending on what's needed.

I was just concerned about asthetics, but if the pipe breaks I will certainly run the new ones above floor.

I'll try the 30 minute circulator jog trick since the timer is on its way and go from there.

Thanks for all the info, guys. I have several possible paths to take now.

T

Tom,
You can't see the pipe unless you look inside the baseboard. It doesn't change the looks of it at all. This way you could eliminate the long pipe under the floor begging to split wide open at the worst possible time. You turn the one loop in the shack to two loops on either side of the room. Then run both back to the warm part of the house where you can connect them to complete the loop. The dual pipes in the baseboard will radiate more heat in the shack. Once you get all the pipes out of the crawl space you can fill the cavity and make the floor a lot warmer.

JJ,

Is the long section of pipe straight and do you have any access at either end?  If so if you could use some of the split foam pipe insulation and put the heat tape in the part of the insulation opposite the split.  Then start the process at the accessible area and feed it forward.  The foam is stiff enough it works well to push so that it slides along the pipe.  I would put a wrap of electrical tape every so often as the foam closes together at the starting point.  You would need to go a size or two up to allow for the size of the heat tape (use the narrow strip stuff) and to provide for easy sliding.

I didn't need heat tape but this worked as a good method of getting some insulation around hot water pipes in a difficult to access area.

Also check for air infiltration between the sill plate and foundation at that point.  I don't know about your area but around here there is a thin foam pad between the sill and foundation that is supposed to seal but irregularities let air through.  You can improve this via caulking the accessible outside area if there are leaks.

Thanks Jared for the heads up. It's a forced air system and I understand the situation now. Let me see if I can make a bargain with my system. I'll shut off just three supplies. That would be the living room / dinining room

TOM any way you could blow some of that warm air from your coal heated room down to the exposed pipe area? Somehow get a digital thermomter to monitor the temp around that pipe?
I know a guy who has been using a pellet stove to heat his crawl space to keep it dry and assist his main heating plant. It has been working pretty good.
Fred

I don't know anything about running current through pipes, but if the efficiency figures for electric heat are any guide, you'll spend more than you save.

It sounds like you need to add a trapdoor to the crawl space. When professionally installed, they're nearly invisible, and a rug will cover anything that isn't. With that access, you can get down there and install proper insulation around the pipes.

For now, the timer on the circulator pump is a good start, but please do yourself a favor and run the numbers for other possible solutions:

• Add a trapdoor and insulate the existing pipes
• Run new pipes inside the heated area
• Use a "one room" gas or oil heater for the shack, and remove the baseboard radiators entirely

Just keep in mind that it's all about payback: don't spend more than you'll recover during the time you'll be in the home. After all, you have to watch out for the family joules!

Bill, W1AC

My solution worked!!!
Two systems running and they "do not see each other".
I'm sending a thanks to the resident HVAC guy Jared.

Fred

There ya go Fred. Those wireless stats are nice. As long as the main unit doesn't short cycle, there won't be any problems. Shot ya a PM.

Thanks
J

Jared,
         thats funny!! You're the first person that I have heard that actually does that!!
The instruction manwell that comes with the little red church house AC-225 actually tells you that it can do that. Although, IIRC it says to use a lower current setting like 75 or 90 amps (or something similar) 175A could do some serious zorchage if the pipes are badly rusted iron pipes.  We used to use my old SA-200 to fire off balky diesels on brutal cold days  ;D  ;D

A looong while Back with a previous YL.... no water in the house.

The plumber tried the welder trick with the city box/ next door neighbor and our house. He burnt out his welder and the pipes were still frozen. Backhoe time; the city payed not a penny fer the new line.

I was yellafied.

 klc

Very good summary, Bill.  (corrected, tnx, Jared)

The trap door is a good idea too.

I am awaiting the timer for the circulator. If I later pop a pipe, I will probably move everything above-floor and that will solve it all.

Tnx for the expert advice, OM!

T

Yeah ya gotta watch it with the high amperage. A quick look at the water meter where the line comes in will tell you if its copper or brass. Around here, most of these house have 3/4" 'L' copper, so you can have at it. If it's brass, then I knock the amps down a bit. If it's steel, it gets a red tag and i go home.

I love this old Lincoln. I can leave it alone for a few years at a clip. Oil, coolant, and slap a junk battery on it and it'll start every time. It has that F163 bombproof flathead 4cyl. I got it off the side of the road probably 15 years ago for $200 and never did a damn thing to it other than cables. It could use a ring job, but it's so good at keeping the bugquitoes from biting.

I was surprised when I saw ads for the sa-200 where guys were paying pretty good change for them these days. That DC copper wound generator is where it's at. I know it'll lay down 7018 like it's butter rod.  

That was Bill. Blame Bill. :D

We have been using Hercules cryo-tek- 100 anti freeze in our system for 25 years here in New Hampshire.I think we have changed it twice in all those years,it contains additives to prevent corrosion.I think it depends on the mineral count of your water,on how often you need to replace the anti-freeze.We have a low TDS here,places by the ocean our much higher.
dale/ka5who

Update:

I received the programable digital timer today and hooked it to a 120VAC relay. This in turn closes the contacts for both the upstairs and downstairs circulators.  I have it programmed to come on every hour for 5 minutes.

So far the system is working FB as designed. The cellar is also warmer cuz of the pipes radiating some heat. I plan to add a digital thermometer that will sample some outside air and enable the timer whenever it drops below 32 degrees. This way I can forget about turning the timer system on or off according to the WX. After all, automation is a good thang.... ;D

All in all, I am happy with this system and think it will work out OK. The coal stove has been heating the whole house for a month now 24/7 and the oil tank gauge has barely moved a hair.  I just know the Middle East is getting worried.

T

Tom,
All you need is a cheap thermostat. Just put the contacts in series with the relay coil.

Yep, you're right, Frank. Why didn't I think of that? 

The spare one I have here is a standard room thermostat and goes down to only 50 degrees, so will have to take a look on the web for something that works below 30F.

I think most are 24VAC too, so will have to find a 120VAC version to handle the timer circuit or add a second buffer relay.


I'm finding that 5 minutes every hour turn-on rate is too often. The pipes stay warm longer when down around 15F outside. So I will try 3 minutes every 1.5 hours for now. 

T

I think you can still buy high voltage thermostats. they have larger contacts. A LV unit may work since the current is low.