Residential Boiler issues, info appreciated!

bigtoons

I have some issues with my hot water boiler. It is a closed system with 3 zones and has antifreeze in it. I have dissected that two of the zone heads need replaced as the valves open but the end switches are shot so I have to replace those and this doesn't look too difficult. The two other items I need to replace are one of the float type air vents directly above the expansion tank and my pressure gauge does not work either (temperature does though). My question is, do I need to drain the entire system to perform these two replacements? I am not sure exactly where I need to shut off all the valves (If I have them in the right places) to perform this. Is it possible to take the air out of the expansion tank, taking the pressure off the system, then make the changes, then fill back up to 12psi? I am not a pro, but love doing things myself instead of paying an arm and a leg for simple service. I know there are times when I need to call the pros, just wondering if this is one of them. I appreciate any and all feedback!

Zman

The answer really depends on how kind the installer was in locating isolation valves.
If you can post a picture we can give you a better idea.

mgdesrochers

You don't have to drain the expansion tank. You do need to drain the boiler to a point below your temp/pressure gauge.
If you have valves in the right spots you should be able to keep the zones pressurized and just drop the pressure on the boiler.

Pictures of your system would allow us to giver you a better answer.

Also if you have anti-freeze in the system you need to capture whatever you remove from the boiler and pump it back in so you maintain the same freeze protection you currently have.(assuming that the anti-freeze isn't diluted beyond the point of no longer providing protection; it needs to be checked annually and recharged occasionally)

bigtoons

Thank you for responding. Here are two pictures that capture what I am dealing with. HVAC guy took some of the antifreeze out and looked at it, felt it and tested it and he said it should be good. Also, should I look into having it piped in to be connected to domestic water source? I would hire that done but I've heard of closed systems evaporating over time and the need for refilling/purging more frequently. Is it worth it to have this done in your opinion? I think the antifreeze was added as the house was foreclosed on and the previous owner stripped it and the bank had it winterized. I appreciate your opinions.

delta T

You may want to get some litmus paper and find out what the Ph of your system water is. If you have any freeze protection fluid in your system, and it has not been checked and charged in the past three years or so, it may have become somewhat acidic. I usually see this manifest early in making things like air vents foul up. Given enoigh time this van eventually lead to substantial system problems. May be fine, just something you may want to check if you are removing water from the system.

Pictures will definitely allow us to help you out. The two items you mentioned are easy to do if you are somewhat handy and have the right valves, and slightly less easy if you don't.

As a side note, why do you have any antifreeze in the system? Antifreeze lowers system efficiency and makes repairs much harder due to having to recover the fluid and reinject it for any repairs, as well as having to maintain the fluid itself.

bigtoons

Thanks for the info Delta. I think I may have been posting the pictures around the same time you commented. Check above for pics and to see why the antifreeze is in there. HVAC guy was in and didn't have any of the strips on him but used a syringe type thing and said the PH looked to be good. Thoughts are appreciated!

Zman

It s hard to tell from the picture but it looks like you are short a few key isolation valves. I think you will have to drain down a portion of your system in order to perform the repairs you are attempting. That means collecting the glycol and then pumping it back in.

Jamie Hall

On connecting to the domestic water system. A hot water heating system should not lose any water (or in this case, coolant). Not to say it won't, but it shouldn't. That said, many if not most are, in fact, connected to the domestic water system through a pressure reducing valve (at the very least) set to maintain heating system pressure -- typically around 15 psi. Opinions -- and codes -- differ on this, but in my opinion, I would like to see the pressure reducing valve followed by a reduced pressure zone backflow preventer. They are a bit of a nuisance -- they need to be tested from time to time, and some jurisdictions require a licensed technician to do that -- but on the other hand drinking glycol is not recommended... and they will prevent any possibility of that!