I have a second home located in Virginia and while the winters are pretty mild, a cold snap can drop the temps to the high teens/low twenties. The house has an unconditioned crawlspace and I recently spent some quality time down there installing heat tape and pipe insulation on a 20’ run of ¾” copper water supply line that leads to the main water shutoff. The heat tape is controlled by a thermostat block (turns on at 35 degrees, off at 45 degrees) powered by an outdoor GE Z-Wave outlet. This all seems to work well enough but there’s currently no way to tell if the heat tape is actually doing anything. Failure of the heat tape or thermostat block is likely to eventually happen so I’m looking for a temp sensor with an external temp probe that I can attach to the surface of the water pipe to confirm that the heat tape is actually doing something. I have a water shutoff access panel in my front hall closet and I’m thinking of adding something like the Qubino ZMNHID3 Thermostat Module with External Temperature Sensor. The Qubino would be installed in an electrical box in the closet and the temp probe fed through a small (sealed) hole in the floor leading to the crawlspace. I’m guessing I can zip tie the probe to the outside of the water pipe and cover the probe with foam pipe insulation. Ultimately, I’d like to create an HE rule that monitors the temp probe and if temp is 32 degrees or lower turn the z-wave outlet on, monitor the temps for say 2 hours and if there isn't a rise in temp send a text alert.
The property is located 600 miles away from our primary residence and we're only down there approx. 6-8 weeks during the winter so I'm looking for something that's reliable and relatively maintenance free. Crawlspaces suck(!!!) and my goal is to limit the need to enter the crawlspace to confirm everything is working. How well does the Qubino ZMNHID3 wotk with HE and is there another device that might be better suited to the task? Are there any other options I may be overlooking?
How about a fibaro door sensor or similar with a temperature probe attached
It the probe cable is long enough then you could place the door sensor in a more accessible place so you can change the battery as needed.
I have a couple of these as normal door sensors with batteries that have, so far, lasted more than a year.
Yeah, I've been looking at these temp sensor cables which are 3 meters long which would be more than enough length. The Door/Window Sensor would likely be a lot cheaper but the Qubino ZMNHID3 is mains powered which would eliminate dead battery issues as a possible point of failure.
In view of the distance involved to get to the property to change a battery (should it fail) I would probably look for a mains powered solution too
BUT... I would probably look at some form of ac/dc converter to run the door sensor
If it was me I think I'd be looking to put a shutoff valve at a better point in the line...that would make me feel like a real plan B.
I have a similar setup in my garage...but it's the garage in the house I live in everyday...so worst case scenario I'm 15min away from home. Also I would have the trigger earlier than 32degrees. Maybe more like 35 to be safe and give you a warning buffer. Also as a complete backup plan in the event of failure. You could string together some incandescent lightbulbs in that area on another mains powered switch. Worst case scenario you start getting some heat around that pipe to give someone time to get down there. (or a second heat strip on a second outlet for backup)
EDIT: after I hit save...that last plan I think is a good one. Have the first strip fire at 35deg and the second strip fire at 32deg and send a text. Pretty simple rules, straightforward and double the heat protection for failure. (also double the cost) coupled with a mains powered temp sensor of course.
Unfortunately, there's no easily accessible "better point in the line". The water line enters from the street at the front of the house and up and into the crawlspace from the ground approx 5 feet from the foundation. The crawlspace access door is at the rear of the house.
I like the second heat tape idea; a belt AND suspenders
It's also worth noting that cold snaps in that area are pretty rare and seldom last for more than a day. And in talking with neighbors and contractors freezing pipes aren't a common occurrence. Nonetheless, better safe than sorry.
Good to hear. As a bonus, I see that the Qubinos support energy monitoring:
The Qubino Flush On/Off thermostat can measure the power consumption of the connected electrical device and itself has an extremely low power consumption of just 0.4 W.
Any idea if this works with HE? If it does it would be an awesome way to determine whether or not the heat tape is actually drawing current and working.
That was one of my first thoughts but just because the heat tape is pulling power doesn't necessarily mean it's working. But yet something else to monitor. I'd like to know if you find out about the qubino working in hubitat also.
While having a mains powered device avoids having to change the batteries, it's a little more common for these kinds of devices to be battery-operated (or have one of each) because it's the times when the power is out that you have the greatest danger of a freeze.
Of course then you have to check every action step along the way to make sure that you'll actually be able to check on the temperature (or maybe get a notification from the battery device), and there are a lot of points to check, but it's just something to consider.
We're at the property approx 8 times a year for maybe a total of 10 to 12 weeks out of the year. The winter climate is generally mild with daytime highs in the low to mid 50s and night time lows in the mid to high 30s. The occasional cold spell can drop night time temps to the 20s but even then, the daytime temps are seldom at or below freezing so we're not talking long term low temps.
The pipe freeze risk is pretty low and this exercise is more of a precaution. Also, the more likely failure scenario is having a battery powered temp sensor go offline because the battery died while we were back home. Besides, if I lose power my hub will be off line as will be my cable modem, router, etc., so no internet access and no means of sending alerts. At that point the entire system is down and having a battery powered temp sensor probably isn't going to do much good
Agreed. But I think the best case I could hope for here is an alert that the power has gone out. The pipes are insulated. If it was cold enough to turn on the heat tape before the power went out it could be many hours before the pipe temps are at the alert threshold. At that point the UPS batteries would likely have depleted.
Also, assuming I had the UPS powering the hub, my cable modem and router, could I expect that my broadband cable service would still be operating? I don't know the answer to that question but suspect that the cable company equipment would also be out of service.
It has worked out quite well. I'm using this heat tape which has the benefit of being able to be cut to length and terminated.
I ditched the plug-in thermostat plug and am doing everything using an RM rule. The rule turns on the heat tape if the crawlspace temp (measured by a second Quibino dual relay device with a temp probe in the crawlspace) drops below freezing. The rule also sends a Pushover notification when crawlspace temp drops below freezing and when it returns to above freezing. As a point of reference it's currently 32 degrees outside and the crawlspace temp is 43 degrees and the pipe temp is currently 58.9 degrees
As I mentioned in an earlier post winters here are typically pretty mild and the system hasn't needed to turn on the heat tape since I started monitoring the crawlspace temps approx 2 years ago.
Of course, the current situation in Texas, Oklahoma, Louisiana and Arkansas is a shocking reminder of how "typically warm" temps can become atypically cold. But at the end of the day, I have hundreds of feet of uninsulated PEX pipe in the crawlspace and the only thing I'm protecting here is the 3/4" copper coming in from the street to the shutoff located in the house. The main goal was to prevent a cracked/split pipe before the inside shut off which would cause an undetected flood in the crawlspace when we're 600 miles away.
I have been tuning my approach to keeping an enclosed well pressure tank and manifold assembly from freezing. Started with a more "when hell freezes over" approach using proven temperature sensitive bi-metalic switch technology. This connected to a 150watt shop light has served well so far.
You will see from the study done at U of I that the key aspects to protecting pipes is a) insulation from draft, and b) direct mitigation before the ambient temp around the pipe reaches 20F. I chose to engage heat at around 30F on the assembly above...but in the old house I don't start dripping water until 25F.
So I now have a zigbee humidity & temp sensor by the pressure tank to monitor things. I have been tempted to "HA the solution" as you have...but I keep thinking...this is fairly fail-safe compared to battery operated sensors, zigbee relays or outlets, possible communication problems, etc.
At this point I'm glad to have the HE monitoring to alert me to the light bulb being out. In my case if the confined space the assembly is in reaches 27F I get alerted. There's room for redundancy here....and I've been contemplating that with HA....which is why I resurrected your thread.
P.S. The current water pipe circumstances in TX right now underline how all these powered solutions are fruitless. In your case being remote from this location...if you lost power I think some scenario whereby you could shut the service line and open a valve into a sink (all on UPS power) might be beneficial. I once had a similar remote property situation as yours and I rigged a 12VDC valve to a shower head, set the wall valves to drip when the latter was open, then used the bi-metalic switch discussed to provide the 12VDC when the temp in the attic (where pipes unfortunately ran) reached the risk threshold. This worked great in a circumstance where pipes OFTEN froze without this mitigation. I did have the 12V wall wart on a UPS so this would have worked OK if , and only if, the temp dropped to the threshold before the UPS died in the case of a power outage. Admittedly, this was a pretty kludged solution.
