Ideas for a Frozen hot water loop

Steve_95

Hi All,

Fantastic site, I've learned a lot about my single pipe system here.  Also found an excellent Pro here to replace my old boiler (4 years ago).  The steam is great, no problems.

However, I have a hot water baseboard loop on my boiler (piped in 1/2") which hardly worked at all until my Pro tweaked it when he did the boiler install.  He added a spiro-vent and I had heat!

The problem I've had for the past 2 winters is that  on a very cold windy night the pipes freeze somewhere in the loop.

This portion of the house is built over 2 crawl spaces, one has access thru the basement and the other has no access except thru the finished floors above.

At my Pro's suggestion we ran the hot water heat practically 24/7 last winter and it was a bit costly and a waste, but we had no choice.

Now it's the spring and we want to replace the floor with a hardwood and would obviously like to tend to this problem first.

Would foam insulation work?  How about changing to a radiant instead of BBs?

Is this possible/practical? Anything you knowledgeable people can recommend?

Probably have about 40 to 45ft of baseboard, return temp is 140

Thanks

toilburn

hot water loop

Use a heat exchanger for the loop and then you can use anti-freeze in the loop

JStar

?

How much of the 45 feet of baseboard is actual element, with fins on it? He put a spirovent on the loop piping? What temperature did you run the loop at last winter to keep it from freezing?

Steve_95

hope I'm understanding the ?

I estimated 45ft based on the length of the baseboard cabinets.  I know that they all have fins on the piping.

The amount of piping running through the crawlspace(s) would be hard to measure.  There are 3 rooms (addition) heated by the loop and they are stretched across the back of the house and measure approx 300 sq Ft, 140 sq Ft and 70 sq Ft so there is a lot of pipe under these rooms.  When the hot water starts it's run from the boiler it travels about 50 ft to the first BB.

As far as the temp setting, we set the prog. stat for the loop to betwn 70 & 72.

The return water in the pipes is 140 steady and max.  The pressure Gage reads 18 and all BB are on 1st floor. 

As far as anti freeze I'm hesitant for some reason.

Thanks

Steve_95

oh yeah

forgot to add:  Yes the spiro is on the loop at the boiler.

Coany

Freeze stat on the pipe in the coldest spot you can reach

attach it tightly and insulate it well it will kick the circulator just long enough to keep that pipe from freezing.



 is how I would proceed.

The Steam Whisperer (Formerly Boilerpro)

Idea

Adding a full outdoor reset control to the hot water system would probably eliminate the freezing, improve comfort, and save fuel.  If it also had an indoor sensor, that would be even better.  Full reset would keep the water moving constantly through the system at a variable temperature. Freezing could still occur but the liklihood with constant heated water floor is pretty low.  I would insulate and seal air leaks (probably the main problem) and reduce the supply water temperature as low as possble to keep the loop flowing nearly constantly in cold weather.

Steve_95

thanks

Appreciate the replies.

Coany, could you please explain what a "freeze stat" is.  Is it wired back to the boiler?  Might be difficult to get wire run from remote crawl to the boiler room without taking up floor, but willing to do it if it saves oil & $.

Boilerpro, I like the idea of outdoor reset, I've considered that for the steam side, which I currently set back 4-6 degrees with no problem.

The indoor sensor you're talking about, is that related to the "freeze stat" Coany referred to?

How would I reduce the supply water temp?  Mixing valve?

Sorry I'm all over the place.  I've been studying Dan's books but my knowledge is still not too great, but I'm learning-slowly.

I've got a great pro, just not too accessible.  He's busy because he's good.  I'm willing to wait my turn and pay my hard earned $ to get it right.

Thanks again!

Coany

Widely sold for exactly what you are talking about

 a little button of a non-adjustable thermostat that would kick the circulator on when the pipe itself hits 45 degrees, kick it off at 55.(there are ones with other values)  Ideally it would never run long enough for overheating to be an issue. They are not very expensive at all  maybe $40 or so



the trick is putting it in the right (coldest) place along the pipe, attaching it tightly and insulating it well.



Yes, you would have to get a two wire thermostat wire from the freeze-stat back to the boiler and wire it in parallel with the thermostat for that zone( so either turn on the circulator) Don't take up the floor just drill a little hole to snake the wire through. There is always a way.



 they work wonderfully.

Steve_95

great idea!

Coany, sounds like a great way to go and the price is right.  I'm pretty good at snaking wires (done plenty of electrical work) but this one would be tough.  I'd have to fish the wires through blind because the crawlspace where i think the pipes are freezing is completely inaccessible and less than 18 inches high.  And don't know if there ate any obstructions down there. 

Maybe I could go from the pipe to outside, short run (10ft) and then back in to the 2nd (accessible) crawl space to the boiler.  I guess you're right, there's always a way.

Crazy thought, could I wire more than 1 freeze stat if I wanted to cover two different areas of pipe?

Thanks again! Gotta love the WALL!

Paul Fredricks_3

Remember?

Years ago there was a small control with an outdoor sensor. When it got down to 30° it would kick the circulator on for 5 minutes every hour. At 25° it would kick on every 50 or 55 minutes...and so on. I can't remember the name of it, but we put a lot of them in and they solved these problems. Maybe it was a freeze guard?



Of course, the best way is to seal up any gaps in the siding or foundations. That's where the real problem is.