Temperature sensors on each rad, wifi

Todd_33

I've been in another thread about cold radiators. It was suggested that some rads were vented too much, causing others to no heat. 9 unit apartment building, 5 rads per apartment. I've been mucking with heat balance since buying the building 17years ago. Thinking battery operated, wifi, cheap, individual temperature sensors on each rad would go a long way toward fixing. That's about 50 sensors.  I've used tempstick stand alone but cost is now $145 each. I'd like a sensor right on each rad, so has to handle 212+ degrees.  Has anybody tried this and does it work? Thanks.
Todd

ethicalpaul

I've used the Govee sensors. They are like $35. They are OK, but not for remote live monitoring...but would work for looking at temperature over time after the fact (see below). You put one on your main near your boiler to be the reference point for the start of a call for heat. By the way, how do you determine when to call for heat? Just a timer based on the outside temperature? But I digress.

- They aren't really rated for steam temps but they worked fine and were not damaged by the temps. You can always put a consistent amount of insulation between them and the radiator/pipe, and then with observation you can tell "when is the steam there". But I just set it on my radiator, it was fine.

But you have some problems that I don't:

1. These cheap wifi/bluetooth devices require you to be on site on the same network or within bluetooth range. The devices store/log the temperature over time and then when you want, you connect to them with the app and it downloads the logged data to your phone. Your units are probably not all within range. But maybe you have a public hallway from which you can grab the data.
2. The batteries last for a year or two max, then you'd have to go around to all the sensors and replace them.
3. You have a lot of radiators, so a lot of sensors, and will drown in data and device management. I would say don't measure every radiator, but just the main one or two in each unit.

Others who have experience with real commercial solutions will add their experiences probably but expect $$$

Todd_33

I did finally go with one sensor in the main living space of each apartment. I used yolink brand and it's been a real help in balancing the apartments.. thanks for the input..

leaking

I bought cheap room sensors , two different brands for about 250 for 12 units . First they are cheap and were not calibrated. One set I can not calibrate , the other yes. I also bought 12 cheap Taylor thermometers, and one 40$ certified glass thermometer from Grainger . What ever you buy like Taylor might say “ calibrated “ but this is bs. They are up to 2+ 2-. I loosened the glass mercury tube so it could slide up down. Put them all on a table and the certified unit. Then adjusted them all to match the certified unit . Then glued them down. First you need to know the real temp. All iR thermometers are printed as inaccurate on their specs ! So that’s not 100% accurate. Why why measure a radiator? That sounds wrong . You need to start with accurate room temps , not radiators . Then pitch radiators , check for leaking valves - repack. Remove vents that don’t open or never close. Check basement mains for pitch. Boiler for closing vents. Then start to balance with different vent sizes . And that’s a whole different job . But hot apartments get cut. Cold opened up .
Yesterday I just taped up clear plastic over my pipes and the fiberglass batts I put on them . I had many areas that did not have tight seams . Today that area is 1f hotter , then I found a pipe over pitched and as it went 90 degrees zero pitch . I raised a part to give pitch to the run . Tenant texted it’s finally getting warmer . A lot of things need checking on old buildings.

KarlW

If you really want to go smart, for a multi-family building you can go with TRVs and Meross valves (there's a couple others on the American Market as well.

https://shop.meross.com/collections/smart-thermostat/products/meross-smart-radiator-thermostat

These open and closed based on the digital temperature reading temperature of the valve. You can also buy remote sensors for the system - Meross makes a sensor like Govee that can control the valve instead of the valve's sensor. For a multi-family unit where the boiler operates independent of room thermostats (or district heat in those extremely rare locations), this could be the answer you are looking for. The big problem is you'd have to be technically savy to use these.

A simpler version of these for TRVs is the Honeywell HR90:

https://www.resideo.com/emea/en/products/comfort/radiator-valves-and-thermostats/radiator-thermostats/hr90-therapro-electronic-radiator-controller-hr90/

These are dumber controls that are about as easy to program as a 1990s VCR, but do the same thing. Unfortunately, you wouldn't get any feedback from them except your tenant's complaints.

In Europe, Honeywell sells the HR92 - this, like the Meross, allows programming and synchronization. The problem with the HR92, along with iPhone-era fully smart systems like Netatmo, Tado, and Eve is that they broadcast over a frequency that is a no-no in the USA.

I have self-imported a European smart valve system, I can elaborate on it and it does have problems, but I think most of my problems are solved as your boiler feeds 45 radiators instead of my 14.

rynoheat

I spent a ton trying different wireless sensors for my home automation system and most smart home temp sensors suck. They're poorly calibrated out of the box, and even if you can program temperature offsets the error is not always linear. Also any wifi sensors either get poor battery life or don't update often enough.

What I found that works well is Acurite 06002M 433mhz sensors. ~$17 each, good calibration out of the box and they last ages on 2 AA batteries. You do need some other hardware to get readings from them, but a cheap SDR stick can read from them with good range and can be integrated into a lot of different software.

Bodycount

I recently purchased the Govee temp sensors and main unit.

they connect via WiFi and do an adequate job.

Initially I thought I would be able to monitor off-site (remotely) but basically it data logs the temps and it can be uploaded when in proximity of the main unit.

Todd_33

I've had pretty good luck with the yolink brand system for temperature sensors on WiFi. The app works good too. I looked into the meross system but I think it not for steam.. I'd like to find a steam radiator vent or valve that works with WiFi...Thanks everyone for your input.

KarlW

To elaborate further, the Meross solution is quite doable. TRVs and smart valves are your best bet. I’ll give my story and give you a way to make it work at the end.

I have a two-pipe system with smart valves TRVs on 11 of my valves and TRVs with dial knobs on 3 more radiators, and traditional screw valves on an additional 3(?) radiatiors. Here’s my a radiator valve and the smart app for my setup.

Right now, I am using a Netatmo system. the great news about the Netatmo (along with Tado and others) system is that have an integrated thermostat that can activate the relay and create steam on demand when a valve calls for it, not just when the thermostat room (not close my coldest room) loses temperature.

Unfortunately Netatmo is one of many systems that use the European 868mhz system (common for proprietary HVAC) to control the valves. This frequency isn’t allowed in the US - we use 915 mhz or so for the same things. This combined with our small market is the main reason why smart valves are largely a European thing. For this and other reasons: getting off the cloud, lack of sensors to control the room (only temp measured is at the radiator), and the difficulty in acquiring additional valves I am looking for a new system.

I get a vague sense that the steam in your apartment is one-pipe. If that’s the case then you need the one pipe TRVs at the steam vent, not a standard one for water or two-pipe steam.

Here’s and example: https://www.supplyhouse.com/Danfoss-013G0140-Thermostatic-Rad-Valve-w-Vac-Breaker-1-Pipe-Steam-5551000-p?srsltid=AfmBOop-8r0Uw5Qw8QRCyiRioQUDHdLsG4vTsZCM6iHLwCcHl8_rqp_b

The real problem is that you need to do it on each radiator, and it adds up to big $$$, hence why I still have radiators without TRVs.

You’ll also need a pressure control - when you heat an EDR of 100 instead of 500, your boiler is massively oversized and a pressure control is how you avoid over-pressuring and in my case, massive water hammer.