End of Season Report - How's my boiler doing?

fentonc

@In_New_England - Thanks!

I do not have thermostat data (although I do have the circulator status, which is on if any of the thermostats are calling for heat). I designed my setup to be 'minimally invasive', so I didn't put current transformers on the thermostat lines - just two light sensors clipped onto the boiler control board to monitor the 'circulate' and 'fire' status lights, and then temperature probes on the supply/return pipes for each zone. It would have been nice to collect that data precisely for the whole season, but I have logic in the program that's logging all of the data which can do a pretty good job inferring which zones are active by monitoring the change in temperature while the boiler is firing.

The most surprising part was that it actually ran without issue for 4 straight months!

My initial thought was that maybe the circulator was running too slow or something, but I think the low delta-T disproves that theory - there's no way around the fact that the boiler is just injecting heat way faster than anything can dissipate it.

I had mentioned to the guy that services it every year (and installed it) that it seemed way too overpowered, and he mentioned the possibility of capping off some of the burner tubes (I think this is called 'down-firing'?), but I've read mixed things about whether or not that can cause other problems.

On the bright side, I should be armed with excellent data now for possible replacements.

pedmec

as i said in my post, i try to avoid cast aluminum heat exchangers. that is what Bederus uses. the acidic condensate sheers the aluminum off the block and if not maintained will harden like cement. boiler is, from my experience, pretty much dead.

install a gb142 and customer didn't want to pay for the pm. so for 6-7 years it just sat than an ran until one day the boiler failed. opened it up and I couldn't believe it. looked like a block of concrete. i tried to chisel it off but it was nearly impossible to get it back to new. got it working but it was replaced a short time later. never seen a boiler do this before.

Dont know if anybody has any tricks up there sleeve to clean it at that point. i haven't read or heard of anything that you can do. maybe somebody here does. and the weil mclain ultras had issues with corrosion holes forming on the bottom of their cast aluminum heat exchangers. lots of warranty claims that they had to honor. that's why not all mod/cons are the same.

Robert_25

fentonc said:

I'm just an enthusiastic home owner, but I set about trying to understand and characterize the heating system in my house this winter.

Your data collection is awesome. I have thermostat data from my smart thermostat, but the best I can do for my boiler is reading the hour meter and noting it in a logbook. I would like to find some sort of "counter" that can count the burner motor power cycles.

Jersey2

You can get a digital recorder that has the record when it hears sound function(VOX). It's not the best solution though. I put my recorder near the boiler, and a timex watch that beeps every hour to give me an idea about how many hours pass before it runs. The recorder records the beeps from the watch and I note what is the next hour before starting. Listening to the audio is fun, you hear Beep Beep Beep then the boiler going on, then beep beep :-) The recorder will not record the entire boiler run because it gets used to that sound level and pauses, and records again to the sound of the boiler stopping.

In_New_England

@Jersey2 that is ingenious data logging! I thought about attaching a digital thermometer chip to the in and out boiler pipes, a tap on the thermostat line and current sensors on the circulator pumps.

All of these should be existing inputs to the boiler control board and it would be great if there was some way to use the info from the boiler.

fentonc

Doing this with a microcontroller board like my setup is pretty straightforward if you want to collect a lot of data (I used light sensors to monitor the status LEDs because I had some lying around and it was non-invasive, but adding some relays or current transformers would also be pretty easy), but they make electrically-actuated 'pulse counters' for pretty much this exact purpose in industrial settings. Check out this one, for instance. I think it basically just increments once every time it sees electricity on its input.

t300

fentonc, 2 years later, how has the data from your Boilertron helped to optimize your system? Great job on using inexpensive tech to get all this data. I'm building similar system for my modcon, mostly to satisfy DIY homeowner curiosity

hot_rod

JakeCK said:

The issue with modcons is that they absolutely require yearly pm to continue to operate for decades. Which eats up those fuel savings quickly. 375$ a year in savings is nothing. Now I can do my own yearly pm on my almost 40 year old boiler, the only thing I can't do is a combustion analysis. 

Don't get me wrong I like new technology, but going from a ci to a modcon... Is a stop gap measure at best in my opinion. Keep the ci, install a buffer tank and go the air to water HP route. Now you have a dual energy source heating system that is 3x as efficient than the best modcon. 

I have owned a dozen different mod cons in my properties. I've never serviced them yearly? The Laars Mascot went 16 years with just two services. It really depends on what they breath and the burner being dialed in exactly to spec.

If you open one after one or two years and it is spotless, no need to open it yearly. A handy person with a combustion analyzer could do their own disassembly and cleaning. Maybe better that many pros

The bigger killer of mod cons is crappy fluid. Plugging or coating the HX surfaces takes them out quickly. Here are a few different brands, fairly thin metal .040 wall thickness.

fentonc

@t300 - the biggest impact was me just getting a very good understanding of how it all worked. Comfort-wise, I got a thermostat with a wireless sensor for the 2nd floor and relocated the sensor to one of the smaller bedrooms. This completely stops the overheating in the small bedrooms and lets the main bedroom run a few degrees cooler - it was very easy to install and vastly improved comfort. 

This year I built a PLC thing that sits between the thermostats and the boiler which performs zone synchronization, a limited thermal purge and “de-thunking”, where it halts the circulator before shutting off the zone valves. The de-thunking worked perfectly and we haven’t heard it all season, the thermal purge after a run probably helped a little, but I didn’t quantify it carefully, and the zone sync did work amazingly well at extending burn times, but was tricky to get working in a way that didn’t make the house annoying uncomfortable at times. I wound up disabling or minimizing the setbacks more to get the synchronization to work better, so a lot of the savings were probably eaten up by running the temps warmer than I otherwise would have. I have a much better understanding of why it didn’t really catch on (especially during the shoulder seasons).