hot water radiator system - additives?

JPL

Hi, all… Was hoping to get professional opinions on this. I have a cast iron Weil McClain CGA7 boiler, about 20 years old. The heat emitters are both cast iron radiators and cast iron baseboards. Over the years, the system has been drained and refilled, perhaps 10 times. This was due to replacing/adding heat emitters, changing to a primary/secondary loop, adding zones, etc. Over the last two years, the boiler has started making noise — the hotter and more it is cycling, the noisier it is.

I've purged to make sure it is not air trapped in the heat exchanger, so I think it is probably calcium build up. I've seen additives on the market which are supposed to address this. But think I have heard they are not a good idea and could lead to more problems down the road.

Any thoughts? I'd hate to have to replace a boiler that is otherwise working, but realize that if left unaddressed, the problem could evolve into something more serious in the future.

Thanks!

hot_rod

Noise can be caused by limescale build up on the boiler castings. This is not uncommon when water is changed often. How hard is the water you fill with?

Anything over 7-10 GPG is too hard for boiler fill water. Check the boiler manual for water spec.

I would use an acid based cleaner for what you describe. The basic detergent boiler cleaners are not so good if you have hard water scale build up.

This is a good % citrus acid based boiler cleaner. I would mix it at 20%.

After cleaning refill through a DM cartridge

I've used Hercules Sizzle, it is a strong hydrochloric acid and needs to be handled carefully.

JPL

Thanks, Hot_Rod! I really appreciate your help!!

I am not sure what the GPG of the city water is but suffice it to say the water is relatively hard based on deposits that build up on plumbing fixtures (i.e., toilet rims). I am curious to know now, so will follow up with the City to see if they have documentation, and also try to find the boiler spec.

I'll get the Axi-Therm cleaner and PuroPal cartridge. Sounds like a great plan. I do have one follow up question, though. Should I clean the entire system - circulating the cleaner through all the radiators? Or should I isolate the heating circuits and clean just the boiler? Since it is primary/secondary loop piping, I could isolate the loops and just run the primary circulator.

Thanks, again. Your help is very much appreciated.

hot_rod

if you csn isolate the boiler you will beed a lot less cleaner

the boiler probably has a drain on the bottom, so you heed a connection near the top

Pump cleaner in top circulate through boiler flush out the bottom

A kit like this has hoses , pump, acid, and bucket to make it a simple task. They are fir tankless water heaters, same cleaner

Plumbing supply, hardware stores, box store , harbor frieght, Amazon has them

Send a pic of the boiler piping, maybe there is an easy connection on top, at the air sep or purge valve

kcopp

I Seriously doubt that it is calcium build up in a closed system.

Its probably just some sediment. Best option is to flush it out w a hose and some water pressure A cleaner MAY help loosen it up but physical pressure it really the only way to loosen it up.

JPL

There is a purge valve at the top of the boiler and the drain valve at the bottom, so this should be relatively easy. I can isolate the boiler (which holds 3.7 gallons), add the cleaner from the top, circulate for some period of time by energizing the primary pump, and then flush out with some back pressure using a hose connected to a nearby utility sink faucet that has a hose thread. I'm thinking after all that, it might make sense to drain the entire system and refill using the PuroPal cartridge to make sure all the water in the system is demineralized. I think I have a plan!

Thanks for your help!! Much appreciated.

hot_rod

I would put the cleaner in, circulate, let it sit for a few hours, circulate some more, then flush with good pressure from a hose.

Fill thru the cartridge, purge and add conditioner

JPL

Picture attached

boiler piping.jpg

hot_rod

Isolate the secondary pumps at the iso valves.

Turn off the fill valve

Drain off the pressure at the boiler drain

Open the top of the air purger and dump in cleaner.

Maybe remove the vent on top of the boiler add another hose valve there, use a ball valve type hose valve.

Circulate the cleaner for an hour or more

Drain the cleaner, connect a garden hose to the top valve you added, power flush out the bottom boiler drain. Keep pressure under 30 psi or the relief will pop.

Looks like a y strainer by the yellow boiler drain. You need to disassemble that after the purge, gunk will be collected there. Take the basket out on the large nut, if you can.

JPL

I checked with the City and they said the hardness rating is consistently 8-9 GPG, so probably borderline. I'll clean and refill through the PuroPal. Does anyone know where I can source the Axi-Therm Clean Boiler? I can easily get the Axitherm 5 or 10, but having trouble finding a source for the Clean, which looks like it might be a stronger cleaner.

4GenPlumber

I have used Sentinel products with great success. You can get them at supplyhouse.com. There are multiple formulations for different applications, so look up what each does (sorry I forget which I've used). There is one to dissolve any build up. You add it to a boiler drain from its pressurized can after bring pressure to zero. Run it for a day of heating, then drain and purge all lines. Then there is another different formulation to add to maintain.