Propane boiler baseboard pipe bursting prevention

Users who are viewing this thread

rfhjr

New Member
Messages
12
Reaction score
0
Points
1
Location
North Carolina
I have a propane boiler and was writing to ask the best way to handle frozen baseboard heating in the case of a power outage. If the baseboard freezes how is the best way to try and keep the baseboard pipes from bursting. Since it is an open system would it be best once the power is restored to not have the hot water circulate and let the baseboard thaw gradually. There is a valve on the baseboard return line near the boiler should that be opened to relieve any pressure. I have gas logs in the house but they may not be enough to keep the baseboard from freezing as it is an old farmhouse which sits on the ground and does not have much of a crawl space. The baseboard is on the ground floor electric is on the second floor.
 

fitter30

Well-Known Member
Messages
2,202
Reaction score
350
Points
83
Location
Peace valley missouri
Best protection is glycol in the system. Has to be made for boiler / chilled water system 30% minimum by volume because of the inhibitor. Don't need to protect to freezing just bursting.
 

Dana

In the trades
Messages
7,889
Reaction score
502
Points
113
Location
01609
Best protection is glycol in the system. Has to be made for boiler / chilled water system 30% minimum by volume because of the inhibitor. Don't need to protect to freezing just bursting.
Can't put glycol in an "...open system...", which I took to mean it's running potable water in the baseboards.

In most of NC it's possible to freeze protect an old farmhouse with systematic upgrades to the building envelope, but it's not cheap. What ZIP code (for weather data and ground temperature purposes)?

The first and most cost-effective thing to do is to air-seal the attic floor and the crawlspace/foundation walls to remove the lion's share of the stack effect outdoor air infiltration drive. When it's warmer inside the house than outside the lighter-warmer air floats out the top of the house, sucking colder-denser air into the crawlspace, presumably where the most vulnerable plumbing lives(?). If there is room to work down there, an inch or two of closed cell polyurethane foam sprayed directly on the foundation walls can be surprisingly effective at "earth coupling" the crawlspace to the ground temperatures, which means with no air being sucked into the crawlspace it's temp won't drop more than 5-10F below the deep subsoil temperatures. The foam needs to start at the subfloor at the top of the band joist and foundation sill, and run all the way down to the floor level. Before spraying there needs to be a heavy ground vapor barrier installed, lapping up a few inches onto the foundation, with the foam then coming down over the top of the vapor barrier to make a nearly perfect air seal. That prevents radon & other soil gases from getting sucked into the house from stack effect drives.

If there is NOT enough room in there it can be done from the exterior (possibly with sheet foam rather than spray), but it's more complicated, wtih a lot of details to get right, and may require some digging.

With the top & bottom of the "stack" air sealed and insulated the first 90% of the problem, but air sealing and insulating the walls still matter. The construction type and material stackup of the walls will dictate how and if the walls can be safely insulated, and how it's best air sealed.

Contrary to most people's intuition, most of the air leakage from windows isn't the seams or weatherstripping between the sashes & window unit, but rather leakage through the sash weight pockets to the seam between the casings & walls, which are easily caulked. There are inexpensive aftermarket pulley seals that work with most antique single & double hungs. Of course the window & door weatherstripping matters too, but that's the more obvious air leak.

If you have single pane windows without storm windows, exterior low-E storm windows can do a lot for tightening up window leakage too, while cutting direct heat losses by more than half, making the window a net heat-gainer in winter. During the cooling season the hard coat low-E coating on the interior facing side of the storm window also cuts the unwanted solar gain by about half. Even though the glass is more expensive than clear glass, in most markets low-E storm windows have a very quick payback on heating/cooling energy use- about 5 years vs. 10 for the cheaper clear glass storms of similar quality.
 

John Gayewski

In the Trades
Messages
815
Reaction score
203
Points
43
Location
Iowa
A power outage should only effect electricity. A generator would cover you it's pretty simple but likely not cheaper than closing your system.

What exactly do you mean by an open system?
 

John Gayewski

In the Trades
Messages
815
Reaction score
203
Points
43
Location
Iowa
DHW runs through fin tube and system feeds faucets.
Hoping that's not what they mean. If it is, bursting pipes isn't the only reason to separate the systems. Besides it being cheapest easiest way to prevent piping freezes its also more hygienic and comfortable.
 
Last edited:
Top