ldavisfl
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I am not sure whether this falls under water heating or plumbing. I have read threads on here about hot water recirculators, including RedyTemp units which use the cold line as a return. I am aware of their benefits and drawbacks.
I am considering a RedyTemp pump, but for a slightly more unusual reason. I built a detached garage with a heated guest unit above. There is an exterior 18 foot long freestanding connecting wall between my house to the garage, and through this wall runs my hot and cold CPVC water lines to the garage (along with sewer, electric, etc). It was the only way to run the lines cost effectively.
It doesn't take very long for hot water to reach the sink in the new space, as the run is only about 30 feet (the water heater is right inside my basement where the pipes enter the wall from the house.)
However, I am concerned that in the winter, the 18 feet lengths of hot and cold pipe in the outside wall could freeze. I did insulate the pipes carefully (foam segments + pvc jackets), and the wall is fairly well sealed. I am not concerned about a few hours at freezing temps. I am worried about temps dropping to 15 F after several gloomy days in a row. This happens 1-2X per year here.
The plumbing inspector told me there should be no problem, and this may be the case if the water is regularly drawn through the pipes. But in reality the fixtures in the new space go unused for days at a time. I believe it is completely possible for those lines in the connecting wall to freeze. The damage would be relatively minor (as the burst would not be inside a living space) but it would definitely be a pain.
My idea is to install a RedyTemp unit in the guest unit as a way to ward off off pipe bursting within the wall. I do have a non-switched outlet under the sink.
I imagine I would only operate the pump only in the winter season. Also, I would set the temp to be something like 90F, which would be higher than the room's air temperature, but not excessively high. When the temp drops below 90, a fresh slug of water would be drawn through the wall sections. I think there would be some guessing as to the set point required to ward of freezing.
Another enhancement I have thought about is to open the connecting wall (remove a siding panel... easy) and to strap a fixed set-point thermostat to the cold water pipe, running the thermostat wire back into my house basement. Then, I would use an Insteon (home automation) relay controller to send a signal to an Insteon appliance module controlling the RedyTemp. Thus, every time the temp dropped to near freezing, the RedyTemp pump would come on until the thermostat on the cold pipe warms up.
I realize that some professionals don't like recirculators that use the cold line as a return. However, I think in this limited case, it really makes sense because warming up the cold line is exactly what I want in this case. Besides, right now the cold water is about 40 degrees so a little warming couldn't hurt. I do realize that hot water could briefly come out of the cold taps, but the supply circuit here is quite short so it would cool down quickly.
Any thoughts on this are greatly appreciated. Do you see any downfalls to this solution? Other ideas I've considered include adding a return line, but this wouldn't protect the cold line from freezing and I would have to open all the walls. Another idea is to add pipe heat tape but having such tape enclosed in the connecting wall is simply unacceptable to me due to fire risk.
In any case, I was going to install the aforementioned thermostat first, to see if pipe approaches freezing at all. It's possible that freezing won't be an issue and I won't need to worry about it. The wall is framed from 2X10 pressure treated, with siding and brick on one side and hardee siding on the other.
I am considering a RedyTemp pump, but for a slightly more unusual reason. I built a detached garage with a heated guest unit above. There is an exterior 18 foot long freestanding connecting wall between my house to the garage, and through this wall runs my hot and cold CPVC water lines to the garage (along with sewer, electric, etc). It was the only way to run the lines cost effectively.
It doesn't take very long for hot water to reach the sink in the new space, as the run is only about 30 feet (the water heater is right inside my basement where the pipes enter the wall from the house.)
However, I am concerned that in the winter, the 18 feet lengths of hot and cold pipe in the outside wall could freeze. I did insulate the pipes carefully (foam segments + pvc jackets), and the wall is fairly well sealed. I am not concerned about a few hours at freezing temps. I am worried about temps dropping to 15 F after several gloomy days in a row. This happens 1-2X per year here.
The plumbing inspector told me there should be no problem, and this may be the case if the water is regularly drawn through the pipes. But in reality the fixtures in the new space go unused for days at a time. I believe it is completely possible for those lines in the connecting wall to freeze. The damage would be relatively minor (as the burst would not be inside a living space) but it would definitely be a pain.
My idea is to install a RedyTemp unit in the guest unit as a way to ward off off pipe bursting within the wall. I do have a non-switched outlet under the sink.
I imagine I would only operate the pump only in the winter season. Also, I would set the temp to be something like 90F, which would be higher than the room's air temperature, but not excessively high. When the temp drops below 90, a fresh slug of water would be drawn through the wall sections. I think there would be some guessing as to the set point required to ward of freezing.
Another enhancement I have thought about is to open the connecting wall (remove a siding panel... easy) and to strap a fixed set-point thermostat to the cold water pipe, running the thermostat wire back into my house basement. Then, I would use an Insteon (home automation) relay controller to send a signal to an Insteon appliance module controlling the RedyTemp. Thus, every time the temp dropped to near freezing, the RedyTemp pump would come on until the thermostat on the cold pipe warms up.
I realize that some professionals don't like recirculators that use the cold line as a return. However, I think in this limited case, it really makes sense because warming up the cold line is exactly what I want in this case. Besides, right now the cold water is about 40 degrees so a little warming couldn't hurt. I do realize that hot water could briefly come out of the cold taps, but the supply circuit here is quite short so it would cool down quickly.
Any thoughts on this are greatly appreciated. Do you see any downfalls to this solution? Other ideas I've considered include adding a return line, but this wouldn't protect the cold line from freezing and I would have to open all the walls. Another idea is to add pipe heat tape but having such tape enclosed in the connecting wall is simply unacceptable to me due to fire risk.
In any case, I was going to install the aforementioned thermostat first, to see if pipe approaches freezing at all. It's possible that freezing won't be an issue and I won't need to worry about it. The wall is framed from 2X10 pressure treated, with siding and brick on one side and hardee siding on the other.
