Frozen pipe

My downstairs 1/2 bathroom is in an addition that has only a very small crawlspace (about 1 foot high and about 8 x8 feet square) with separate cold and hot water pipes running to the sink. Since the steam boiler hasn't been on, the basement is quite cold (about 45 degrees) and the crawl space even colder. With the very cold air the past couple days, I was good about leaving the cold water spigot dripping but totally flaked on the hot water one and of course, that pipe froze. There is a small steam radiator in the bath. I guess I discovered the one pitfall to using the stoker in my first floor living room - the heat from the oil burner pushing steam around a bunch of pipes isn't there to keep the water moving in very cold weather.

I'm trying to defrost the pipe by running the boiler full steam ahead (pun intended) to warm up the basement some and also have a space heater blowing some hot air into the crawl space area. I took the insulation off the steam pipe going to the radiator in there so it would also give some radiant heating into the space. The hot water spigot is open. It's slowly warming in the crawl space but the pipe remains frozen at this point and it's been several hours since I started.

Sadly, a potential frozen pipe in this space was a known issue to me as pointed out by the plumber who I use and used to service the house with the previous owner. He told me I needed to open up that crawlspace some by knocking out more of the block/cement/rock wall foundation between it and the rest of the house but I never got around to it mostly for lack of the proper tools to do it with. You can bet it will be at the top of my honey-do list for next week

At this point, I don't think the pipe has burst. But if it has, I've located the hot water shut off valve to that part of the house (which will take the hot water out of the kitchen too so that would suck). In the meantime, anything you guys can suggest for speeding the process along? It's only a half inch copper pipe servicing that spigot so I'm amazed it hasn't thawed yet. I'm not sure a blow-dryer would work any better than the space heater because of a lack of accessibility in the space - the opening to it is maybe 6 x 8 inches - just enough to get the three pipes in and the drainage pipe out. I do feel that the cold air is being displaced by warm air I'm forcing in there because I can feel the draft coming out and the floor in the bathroom is nice and warm

Will heat tape work retroactively? I'm not confident I can reach in there far enough for it to do any good however. I wake at 3am for work so bedtime is quickly approaching and I would love to have this unexpected project wrapped up before then and I am not comfortable leaving the space heater on down there while I slumber.

Any ideas other than using an open flame?

2 thoughts<
1) do you have an old clothes iron? maybe you could put it directly under the pipe
2) a little disc furnace - ceramic heater are pretty small but it you already have a space heater it's probably the same difference

Also take the screen off the faucet that way if there is slush in the line it can push through

After you thaw, if you don't use the facility can yo shut the water off and drain the pipes?

One quick way is to use an electric welder. You connect the welder leads such that the frozen pipe is part of the circuit. The pipe electrical resistance becomes a heater element and melts the ice.

Screen just came off. I would never have considered doing that.

Not sure about draining it however. I can empty the hot water heater easily enough - would doing that give backflow to drain the pipes it's feeding?

I don't have a welder so that won't work.

I set up a few candles one time directly under the frozen pipe. About 45 mins later, free of ice. Try it. It's an open flame but you do not have to hold it like you would a torch

My girlfriend, now wife, thought I was nuts. She has seen many more feats of brilliance since but still questions all of my ideas!

I have a friend coming over shortly with proper tools to open the crawl space. Will update soon.

I'm afraid candles may burn too close to the sub-floor above - it is a really small space and every piece of wood in the house is tinderbox dry even with a humidifier running.

Hair dryer works great on thawing pipes and beast part no open flame

Thawed.

Once we got the space opened up I was able to stick the ceramic space heater in there and it thawed some time overnight. No burst pipe

Glad you got it thawed. Hopefully now that it's opened up some it won't freeze again. Seldom does a copper pipe break on the first freeze. It's a freeze thaw freeze thaw cycle that splits them. Each freeze stretches it a bit more, until it finally splits. About the only time a pipe will break on the first freeze is when it doesn't split, rather it pushes an elbow off the corner.

Yanche wrote:One quick way is to use an electric welder. You connect the welder leads such that the frozen pipe is part of the circuit. The pipe electrical resistance becomes a heater element and melts the ice.

Will that work with a MIG? I would think it would just light off the wire in a hail of sparks & fire..

SMITTY wrote:Will that work with a MIG?

Only if you can clamp it somehow. I'd guess, no.

One thing with using a welder, on iron pipe it works great, but copper pipe has little resistance and will tend to overheat the welder real fast, or trip circuit breakers. If you're going to try it, turn it on for 30 seconds, then off for 2 minutes, then again.

They make a pipe thawing machine that's made for the purpose, they are similar to a welder, but cost more. I think they have more windings, but maybe part of the cost is the directions they come with. When thawing copper pipe you have to calculate the length and size and then use a watch with a second hand. You run it for a certain time and then wait. After some minutes you can do it again. They warn that you can melt the solder out of the fittings if not used per directions. Iron pipe you can just hook on & wait til water flows.

As I was hunting around the intertubes yesterday looking for suggestions on what to do, I came across a day old story in the local bird cage liner that had someone burning their house down after trying to use a heat gun to thaw his pipes. It said the pipe got so hot it ignited the wood next to the pipe rather than the actual heat gun starting the fire.