What’s up, guys? So I have an tankless coil in my (Burnham) boiler that I get my hot water from, but I run out of water in about 5 minutes when I’m taking a shower. I had a friend over today and he said it seems like it’s probably a buildup in the coil due to hard water. He said it needs an acid rinse (Muriatic acid?) Has anyone ever done this on their own? Did you get good results? PS: my boiler already has the inlet and outlet faucets on each side of the coil, so it would be easy to isolate the coil. Thanks for any guidance.
…. Find the manual. Most will have cleaning instructions. Once it has built up to that level (assuming you guys are correct in that is the problem) it is hard to get everything clean again.
Do this^^^^ I use a 5% muriatic acid solution to clean calcium from our electric water heater. Not sure if that's a good idea for your tankless.
I work on a bunch of hydronic heating systems and always try to follow cleaning instructions for a particular system. Many times that is not available; lots of info online if you don’t want to hire someone experienced with cleaning them. A few other things that could be causing problems: Something other than build up blocking stuff reducing flow. Boiler not actually running and heating water continuously. I would lean on the buildup side of things but who knows. Once fixed you may want to invest in one of the salt less/chemical free water conditioners. My supply house likes those and the lime juice extract cartridge things.
Thanks, snaple4 . Ok, after some online research, I’m going to buy a submersible pump and flush out the tankless coil with vinegar for about an hour or more. I’ll let you know how that works out. I was going to just replace the coil since that didn’t look too difficult either, but I’ll give the vinegar a try first, since the system is already set up for that. I’ll report back.
Just get a circulator, sweat check valve and 45 gal SuperStor tank from Home Depot which works as another zone on the boiler. I did that and easily get 4 gal/min of piping hot water and it is way more efficient so it save$ money in the long run. https://www.homedepot.com/p/SuperStor-45-Gal-Indirect-Water-Heater-Storage-Tank-SSU-45N/313316154
So, I did the hot water coil flush today. I used 2 gallons of distilled white vinegar. It started out slow, but pretty soon the vinegar was flowing smooth. I let it run for an hour and then switched the hose lines and ran the vinegar thru in reverse for a half hour. Afterwards, I took a shower and didn't run out of hot water. Success! ... I took a video, but I'm not sure how to upload that, so here's a photo.
Upload the video to YouTube and then put the link in here please. It works well, I do it all the time!
That's how I do the maintenance on my Rinnai tankless hot water heater. I used a filter on the hose to catch anything large but didn't see anything huge. I do it every 2 years. Did you see any debris in the bucket when you were done? I would imagine so. Nice job!
No, I didn't see any debris, but the vinegar was pretty black when I was done. I'm going to do it once/year from now on.
