Hydronic baseboard boiler maintenance

[cgrutt]

Sorry this is home system not garage but I know you guys will steer me in right direction. Concerned about gas fired boiler probably hasn't been serviced properly since it was installed (probably 20+ years ago) and I see some troubling signs just wanted to get your input.

1. Corrosion under expansion tank. OK to just wire brush this? Assuming it had a leak at one point that caused the corrosion concerned if I brush off may start leak again.



2. Rust on black pipe main and return. Hopefully just from external oxidation. OK to wire brush and paint (thinking high temp flat black).



3. Rust on circulator pump. Same question as above but is this something that should be preemptively replaced for routine maintenance? It's running fine no issues besides the Rust.



4. Should water main valve be left opened or closed? I assumed it would be closed because its a closed loop but valve has been left opened. Should I do anything to test/maintain pressure reducer?



5. Airbleed/pressure vent. Should this be opened up and inspected/cleaned?



6. Burners - I opened bottom panel and vacuumed under burners. There was a whole lot of dust bunnies underneath but tops of burners look good. Thinking about pulling these out and deep cleaning this Spring is that a bad idea?

7. Main tank/pressure vessel. Can anything be done as far as routine service to extend life? I have to pull panels off to actually see it. Looked underneath and it seemed in good condition from exterior. Should system be drained and flushed after heating season? If so do you add anything to system or just run clean water?

I spent alot of time looking for videos etc but most of what I've found deals with steam boilers not much on forced water (surprisingly). Any good resources/books etc as far as routine maintenance?

Many thanks.

 

[American Locomotive]

1.,2.,3.; The green copper corrosion/build up and the rust on the circulator are ugly, but inconsequential. There is no need to wire brush, clean and paint unless it makes you feel better.

4.; IF the system is completely tight without leaks, you would be correct. You could close the water supply, and the system should operate for years and years without issue. However your system is not tight, and is leaking ...hence the rust and copper corrosion. Just make sure the dial on the boiler says it has like 8-15 PSI of water pressure in it, and you should be good. You can give the water feed a little flick to make sure it's not stuck. Those connections don't appear to be leaking right now, but they definitely were in the past. They might leak in the summer when the boiler is cold.

5.; Don't mess with it unless you have air in the system.

6.; The only maintenance a gas boiler needs is the occasional burner rack cleaning and air band/gas adjustment to make sure it's still burning clean. You can't do this by eye, you will need someone with a flue gas analyzer (or get one yourself and learn how to use it)

7.; Do not flush and drain - that actually reduces the life of the boiler. All iron/steel boilers corrode, but at some point most of the oxygen in the water gets used up, and no more iron can be oxidized. Adding fresh water will bring in dissolved oxygen that will allow more steel to corrode.

 

[Bert_]

Do nothing about most of that. Clean the burners if there is rust in them. I leave the fill valve closed. If there is a leak I want to know. Normally add a little water once a year. More often is a concern

 

[cgrutt]

Thanks! So flu gas analyzer... that's something I don't have....

Good point on O2 in water hadn't thought of that.

My real concern is the circulator pump and cleaning burners, etc.

I think I learned a lot about boiler and Aquastat today but still trying to figure out how this system is actually wired. They are not using the TV terminal to trip relay and Z/W are not jumped but connected separately. There appears to be a separate transformer (external to Aquastat) that the thermostats are connected to. I see the relay closing and circulator starts working but trying to figure out how the system is wired to make the relay inside Aquastat to trip. Thought that would happen when TV is supplied 24V but TV is not attached to anything. Probably activated with the external transformer. Going to try to map this all out so if anything fails I know how to test it.

Thanks for help, much appreciated.

 

[Torque&Recoil]

I'm not an HVAC professional, but I did own a house with hydronic heat for 25 years. These systems are mostly maintenance free. American Locomotive and Bert have good, solid advice. In 25 years, I did have to replace some zone valves (you have only one and it looks new - I had four), and the spring drive coupling on my circulator pump wore out (different style than yours). I did leave my take-up valve open continuously, but probably no need. I never utilized a flue-gas analyzer. Your air bleed looks good to me and fairly new (if it leaks, you will see deposits on top). Basically, I think you should just let it run ! If you are a ******** DIY guy like me, you might want to think of "spares". Depending upon where you live, hydronic parts may not be easily available. I usually had to order stuff from the Internet and 2 day delivery was typical. If you had a spare circulator pump sitting on the shelf, it wouldn't be the end of the world... I see no need for spares for anything else.

 

[cgrutt]

I'm not an HVAC professional, but I did own a house with hydronic heat for 25 years. These systems are mostly maintenance free. American Locomotive and Bert have good, solid advice. In 25 years, I did have to replace some zone valves (you have only one and it looks new - I had four), and the spring drive coupling on my circulator pump wore out (different style than yours). I did leave my take-up valve open continuously, but probably no need. I never utilized a flue-gas analyzer. Your air bleed looks good to me and fairly new (if it leaks, you will see deposits on top). Basically, I think you should just let it run ! If you are a ******** DIY guy like me, you might want to think of "spares". Depending upon where you live, hydronic parts may not be easily available. I usually had to order stuff from the Internet and 2 day delivery was typical. If you had a spare circulator pump sitting on the shelf, it wouldn't be the end of the world... I see no need for spares for anything else.

Thanks. There are actually three zones and I replaced valve in picture (just the actuator not actual valve) in 2022. System is at least 20 years old, maybe older. FIL and neighbor replaced at same time when they brought gas into neighborhood. Neighbor had to replace boiler this past year which is what got me thinking about it. Just trying to prolong the inevitable...

 

[fitter30]

Light rust on pump and return piping isn't a big deal. Extank needs to be replaced in the spring or early fall. What water temp are you running? A outdoor reset control Would save some money on your gas bill. It varies water temp by outdoor temp. Return water temp minimum needs to be over 135° my personal setting is 140°. Don't see very many valves to isolate the extank system probably would need to be drained down. Good time to add some boiler treatment. Rectorseal makes a 8 way treatment sells for less than $20 for a qt. Pump looks like a cartridge pump doesn't have a coupler. Take a pic of it sideways. Pilot is it lite all the time or cycles with a call for heat?

Amazon.com

 

[cgrutt]

Light rust on pump and return piping isn't a big deal. Extank needs to be replaced in the spring or early fall. What water temp are you running? A outdoor reset control Would save some money on your gas bill. It varies water temp by outdoor temp. Return water temp minimum needs to be over 135° my personal setting is 140°. Don't see very many valves to isolate the extank system probably would need to be drained down. Good time to add some boiler treatment. Rectorseal makes a 8 way treatment sells for less than $20 for a qt. Pump looks like a cartridge pump doesn't have a coupler. Take a pic of it sideways. Pilot is it lite all the time or cycles with a call for heat?

Amazon.com

Gauge on boiler reads 190F and about 16-17 psi.

 

[fitter30]

Gauge on boiler reads 190F and about 16-17 psi.

The 190° is pretty hot. Normal is 180° at 0°. Boiler systems normally design 20° difference between the supply and return. Don't adjust water temp or boiler water pressure now. The expansion tank has a air charge opposite the piping end. It will get set up when tank gets replaced. With water temp under 100° pumps off. 10 lbs is 23.1' height
2.31 per foot that is from the lowest to the highest level plus 2-3 lbs more. Tank get set the same pressure. Tools needed to check air change tire gauge 0-50 and a tire pump. Air compressor use just a very short burst. Bladder doesn't have very much volume.

 

[cgrutt]

The 190° is pretty hot. Normal is 180° at 0°. Boiler systems normally design 20° difference between the supply and return. Don't adjust water temp or boiler water pressure now. The expansion tank has a air charge opposite the piping end. It will get set up when tank gets replaced. With water temp under 100° pumps off. 10 lbs is 23.1' height
2.31 per foot that is from the lowest to the highest level plus 2-3 lbs more. Tank get set the same pressure. Tools needed to check air change tire gauge 0-50 and a tire pump. Air compressor use just a very short burst. Bladder doesn't have very much volume.

So the 190F must have been shortly after burner shut down. It was down to about 135 just a while ago. Heat called on and it seemed to drop below 110 for a short while then climbed to about 195 until burner shut off.

I pulled out my Milwaukee temp gun (laser) just for S&G. And was reading at the black iron elbows at bottom (below circulator) which I'm assuming is return. And st top of boiler which I'm assuming is output/discharge. The readings were sort of all over the place but I tried to record the "average" between no heat/no circulator to burner off with circulator running to no burner no circulator. Hope this makes sense. Here are various readings output (top) / return (bottom).

Burner off no heat call 155/125
Heat call circulator on burner off 137/137
Burner on circulator on 156/148
Continuing 175/168, 196/181
Burner off circulator on 195/192
Circulator continuing 216/216 (gauge on boiler at 195)

Hope this makes sense. Seem about right?

 

[cgrutt]

So the wiring has been racking my brain because I was expecting thermostat to be connected to terminals T and TV with terminals Z and W jumped as provided in schematic.



But it appeared terminal TV was not connected, terminals W and Z were not jumped and Thermostat was connected to Z and T. I couldn't figure out how relay was tripping. I think I figured it out but need confirmation that I'm reading schematic right.

Does 1K represent coil on relay with 1K1 and 1K2 representing two separate contacts on that same relay? I believe it does but have never seen a relay depicted that way.

Still, wiring didn't make sense. But I went back again and see that they put a jumper between TV and W. So when thermostat closes and connects Z and T, the coil is basically backfed through W and jumper to T. *** backwards but that's the only way I can see the Aquastat working.

I also see how circulator gets fed 120V and ignitor is supplied 24V through relay (and in case of burner, the high limit temperature switch).

Feel like I learned a lot today but head is spinning lol. Thanks for helping me sort it out.

 

[HoosierBuddy]

Thanks! So flu gas analyzer... that's something I don't have....

As long as your boiler is firing and running OK, you may be good without it. If you have to adjust it....then you need the analyzer. I ran into that earlier this winter on my wall boiler.

https://www.amazon.com/dp/B00B0ZWIEA?tag=atomicindus08-20

Bad news is it's $600

More bad new is it has to be sent in to be recalibrated on a regular basis, so it's not something you probably want to have in your toolbox. I was able to borrow one. While I applaud your DIY approach, in most cases it is going to be worth it to hire a professional who owns one of these if you get to the point it is required (like I did).

With the issue I was fighting, without that unit I never would have been able to track down the problem. Likely would have given up and replaced a boiler that really only needed a $300 part (gas valve).

Regarding the water connection, I leave mine open.

Regarding the expansion tank....most feel like if you get 5 years out of these you've done good. Mine is 19 years old and I bought a replacement to install as soon as heating season is over just on general principal.

 

[cgrutt]

As long as your boiler is firing and running OK, you may be good without it. If you have to adjust it....then you need the analyzer. I ran into that earlier this winter on my wall boiler.

https://www.amazon.com/dp/B00B0ZWIEA?tag=atomicindus08-20

Bad news is it's $600

More bad new is it has to be sent in to be recalibrated on a regular basis, so it's not something you probably want to have in your toolbox. I was able to borrow one. While I applaud your DIY approach, in most cases it is going to be worth it to hire a professional who owns one of these if you get to the point it is required (like I did).

With the issue I was fighting, without that unit I never would have been able to track down the problem. Likely would have given up and replaced a boiler that really only needed a $300 part (gas valve).

Regarding the water connection, I leave mine open.

Regarding the expansion tank....most feel like if you get 5 years out of these you've done good. Mine is 19 years old and I bought a replacement to install as soon as heating season is over just on general principal.

Understood. The burners "look" fine not really something that's needed at least at this point. I'm a tool junkie though so not necessarily put off by cost although currently I have bigger fish to fry so this is definitely back burner (pun intended). I recently completed my Universal 608 and have been toying with idea of doing some maintence type work so it's something I'd definitely consider in the future. Appreciate your comments. Thanks.

 

[fitter30]

So the 190F must have been shortly after burner shut down. It was down to about 135 just a while ago. Heat called on and it seemed to drop below 110 for a short while then climbed to about 195 until burner shut off.

I pulled out my Milwaukee temp gun (laser) just for S&G. And was reading at the black iron elbows at bottom (below circulator) which I'm assuming is return. And st top of boiler which I'm assuming is output/discharge. The readings were sort of all over the place but I tried to record the "average" between no heat/no circulator to burner off with circulator running to no burner no circulator. Hope this makes sense. Here are various readings output (top) / return (bottom).

Burner off no heat call 155/125
Heat call circulator on burner off 137/137
Burner on circulator on 156/148
Continuing 175/168, 196/181
Burner off circulator on 195/192
Circulator continuing 216/216 (gauge on boiler at 195)

Hope this makes sense. Seem about right?

Ir thermometer don't recommend them for measuring pipe temp. K style electronic thermometer than the sensor can be strap to the pipe and insulated. The tridicator thermometer is in a well surrounded by water. There might be a operating control above burners and a wiring diagram back side of cover take a pic of it and thermostat number.

​

 

[cgrutt]

Ir thermometer don't recommend them for measuring pipe temp. K style electronic thermometer than the sensor can be strap to the pipe and insulated. The tridicator thermometer is in a well surrounded by water. There might be a operating control above burners and a wiring diagram back side of cover take a pic of it and thermostat number.

​

The gauge on boiler is mounted at top of boiler and Im assuming is a direct read. I was just taking measurements with a handheld Milwaukee just to see what was happening. The gauge on boiler tracked the Milwaukee reasonably close at the top (discharge?) elbow. No need to respond I was just trying to figure out how unit operated.

BTW, the controller on boiler is a Honeywell Aquastat. Believe model number was L8148E but I'm just going by memory. The high limit temperature switch is a manual dial. It's physically connected to the top elbow so assuming there is a temperature sender inside pipe.


Thanks.

 

[billconner]

The gauge on boiler is mounted at top of boiler and Im assuming is a direct read. I was just taking measurements with a handheld Milwaukee just to see what was happening. The gauge on boiler tracked the Milwaukee reasonably close at the top (discharge?) elbow. No need to respond I was just trying to figure out how unit operated.

BTW, the controller on boiler is a Honeywell Aquastat. Believe model number was L8148E but I'm just going by memory. The high limit temperature switch is a manual dial. It's physically connected to the top elbow so assuming there is a temperature sender inside pipe.


Thanks.

Just had my aqua stat replaced Wednesday. Mine was original to 1994 install. New one looked almost identical to original Honeywell but another brand since Honeywell dropped that product a while ago.

Helpful thread. Added routine change of expansion tank and consider outside reset for my oil fired boiler. Thanks!

 

[cgrutt]

Light rust on pump and return piping isn't a big deal. Extank needs to be replaced in the spring or early fall. What water temp are you running? A outdoor reset control Would save some money on your gas bill. It varies water temp by outdoor temp. Return water temp minimum needs to be over 135° my personal setting is 140°. Don't see very many valves to isolate the extank system probably would need to be drained down. Good time to add some boiler treatment. Rectorseal makes a 8 way treatment sells for less than $20 for a qt. Pump looks like a cartridge pump doesn't have a coupler. Take a pic of it sideways. Pilot is it lite all the time or cycles with a call for heat?

Amazon.com

Sorry missed your question about pump, yes, its a cartridge type Taco 007-F3

 

[finn]

I think a lot of that “corrosion” is simply the result of high ambient humidity in the boiler room, which is likely in your basement.

The copper pipe turn green when the acid core flux and high humidity react with the copper pipes.

A mild citric acid solution should clean up the copper, and improve the eye appeal. The unprotected iron fittings will require a wire brush and some Rustolium or equivalent paint. Ace hardware is running a two /$5.00 deal on their house brand now.

As for the Taco pumps, my local utility was offering high efficiency retrofit replacements to replace the old energy hogs. The deal required replacement by a license professional, but they pay for the labor. Ended up getting them for free from my hvac guy, since there was enough fat in the offer for him to cover the discounted cost of the pumps and still make money on what the program paid for labor. I think I got five or six updated, low energy Taco pumps for free through the program. Moral of the story is to keep on top of what energy conservation programs are out there through your state and utility company.

 

[brewchief]

Expansion tank you have looks to be a filtrol tank, the fitting the tank is screwed into is actually a fill valve and then there is another fill valve on the feed line. The filtrol tank has a piece that sticks out of the threaded fitting and acuates the fill valve.

In most areas a dual check backflow is required on the fill line to prevent the possibility of boiler water contaminating potable water if the pressure in the potable line drops below the boiler pressure.

 

[Airforce_NavyDAD]

Have a licensed contractor do a complete combustion analysis and burner cleaning. You need to have the flue analyzed for proper combustion. There is NO other way. I would also have the pop valves checked or T&P's. I would advise against shutting down make-up water which can be a code violation as well as running the risk of firing on a partially full water jacket if there's no Aquastat. As mentioned before most of the advise you've received is sound.