How to manually increase boiler pressure?

Users who are viewing this thread

ghoustro

New Member
Messages
2
Reaction score
0
Points
1
Location
Minnesota
I have a fairly typical hot water heating system, the main difference being there is a separate boiler for the 1st and 2nd floors of the house (used to be a duplex.) My question is, there is one radiator on the main floor (they're standard old school cast-iron fin radiators) that is fairly cool throughout the top 2/3 of its height. I attempted to bleed it, and air whooshed out for quite awhile, probably almost a minute, with no water coming out. This seemed odd to me so I went downstairs to check on the boiler, and noticed that the PSI had dropped quite a bit. After doing a little research I decided I needed to add more water to the system. I located the valves that connect the boiler to the city water supply and opened them... but nothing happened. One of the valves on the 1st floor boiler was a corroded old screw-type, whereas the valves connecting the 2nd floor boiler to the city water supply were both newer quarter turn (both had two valves with a back flow preventer in between). When I opened the valves to the 2nd floor system, the needle on the PSI gauge jumped, and I could hear the water coming in. So, I'm thinking that the valve that lets new water into my 1st floor boiler is corroded shut.

My question is, is there any way to manually add water to the system to get the PSI back up? The radiators still seem to be heating up OK, but the PSI gauge reads near zero. I'm guessing there is a leak somewhere between the boiler and the cold radiator that I will have to deal with at some point, but for now I just want to make sure the system is going to run OK for the rest of the winter.

Any insight into this situation would be appreciated.
 

Dana

In the trades
Messages
7,889
Reaction score
509
Points
113
Location
01609
By "...manually add water to the system..." do you mean something other than replacing the corroded closed valve so that you can use it, but instead feeding in water at some other point on the system?
 

ghoustro

New Member
Messages
2
Reaction score
0
Points
1
Location
Minnesota
By "...manually add water to the system..." do you mean something other than replacing the corroded closed valve so that you can use it, but instead feeding in water at some other point on the system?

Yes, that was what I had in mind. Maybe running a hose from the utility sink and hooking that up somewhere? Thanks for your reply.
 

Dana

In the trades
Messages
7,889
Reaction score
509
Points
113
Location
01609
The best thing do do would be to replace the defective frozen-closed filler valve with a ball valve.

Short of that, if there is a valve on the system somewhere for draining the system it will usually be a standard hose connection, and you can then run a hose between another hose spigot over to the drain valve. To avoid injecting a lot of air into the system fill the hose with water before hooking it up to the heating system valve. Then, hook up the valve (leaving it the drain valve closed), then pressurize the hose by opening your spigot valve, then carefully open the drain valve while watching the pressure gauge (assuming you can see it.) Pressurize to 12psi, not more, and hopefully you'll be good. Turn the valve off, but leave the hose hooked up.

If there is still air in your radiators you may want to leave the radiator bleeders open as you pressurize the system.

Run the heating sytem for a full cycle and make sure it's pumping well. It will probably have at least some air in the system from your garden-hose filling procedure, but hopefully not enough air to form air locks, preventing flow. If it's not flowing you may have to open up the radiator bleeders and run water into the system from the hose again (which is why you left it hooked up.) As long as it's running 12psi cold, and not more than 25 psi when the system is hot it should work just fine, and eventually the air will purge via the system vents.

While the system is de-pressurized it's a good time to check the pre-charge on the expansion tank, which you should pump up to 12psi (tested with a tire pressure gauge) prior to pressurizing the system.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks