Refill closed loop, hot water boiler/radiators with manual valves


Old 12-09-15, 08:50 AM
Thread Starter
Join Date: Dec 2015
Posts: 4
Received 0 Votes on 0 Posts
Refill closed loop, hot water boiler/radiators with manual valves

I have an old American Standard boiler from 1969 that works great but will be moving a radiator from one wall to another for a kitchen renovation. In doing so Ill be draining the entire system b/c the whole house is not divided into zones nor do I have any valves to close! The system has a manual fill (no pressure reducing valve), expansion tank will also be drained, two story house with the boiler in the basement so three total. Here are the steps I believe I need to take if somebody could lend their thoughts on if Im making a mistake.... Noobie but have done my homework ( I think...)

1) shut of gas to I can fill the system and turn on pump w/o fear of damaging the boiler if water/pressure gets low

2) with all radiator bleeders CLOSED, open the fill valve and turn on the boiler (with gas off but this will start the pump, I think/hope)

***** in writing this im wondering if this will allow the pressure to build like it would with the gas on so maybe shutting of gas is a bad idea??*******

3) close fill valve when pressure gauge on boiler rises and go to nearest radiator and bleed. IF water comes out, move to the next, if not, add more water and repeat throughout the house.

my other thoughts on this are to turn the gas on, turn the heat up and add water like a mad man and run up and down the steps to bleed the valves, add water, race up again, etc etc.
Sponsored Links
Old 12-09-15, 11:42 AM
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
Turn off the power, turn off the gas and drain the system.

Do your work.

Replace the safety valve on the boiler. This should be done every five years.

Replace the pressure gauge as it is likely not reading correctly.

Refill the system to about 28 psi. Release trapped air but do not allow the pressure to drop below about 12 psi during this stage. It is best if you have two people, one to bleed the air and one to add water as necessary to keep the pressure around 12-15 psi. When you have bled out all the air you should have about 12-15 psi in the system.

Depending on the type of expansion tank you have there are a couple of other items to check. Is your expansion tank similar to a gas barbecue tank or is it a horizontal tank up in between the floor/ceiling joists?

Once the system is full of water turn on the power and run the circulator pump to see/hear if the system is full and most/all of the air has been removed. DO NOT fire the burner during this phase. You may need to go through the bleeding of air stage again.

Only after the air has been removed do you turn the gas on and fire the burner.

Lots, lots more. Pictures of your installation will help. Pictures need to be well lit and in focus. Dark or blurry pictures are useless. Don't need any close ups at this point but wide angle shots from far enough back to see how it all is connected. Ideally, high definition pictures hosted on a photo hosting site with the public URLs posted here.
Old 12-09-15, 12:20 PM
Thread Starter
Join Date: Dec 2015
Posts: 4
Received 0 Votes on 0 Posts
Pictures are of the expansion tank, the valve on the tank, the whole boiler system, the pump and its wiring, etc.
Im not sure how to turn the pump on w/o turning on the whole system. thats why I was suggesting to shut the gas off and turn the system on on the thermostat. I understand to bleed the system and fill as I go but getting the sytem to a point where it can be fired safely is where Im most concerned. Name:  image1 [466933].jpg
Views: 959
Size:  31.5 KBName:  image2 [466934].jpg
Views: 986
Size:  32.5 KBName:  image3 [466935].jpg
Views: 921
Size:  34.9 KBName:  image4 [466936].jpg
Views: 987
Size:  37.6 KBName:  image5 [466937].jpg
Views: 842
Size:  30.9 KBName:  image6 [466938].jpg
Views: 901
Size:  32.6 KBName:  image8 [466940].jpg
Views: 1413
Size:  29.9 KBName:  image9 [466941].jpg
Views: 893
Size:  30.3 KBName:  image10 [466942].jpg
Views: 952
Size:  26.3 KB
Old 12-09-15, 02:28 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,026
Received 42 Votes on 37 Posts
Turn off the gas valve to pilot at the boiler.. Bottom left of boiler here in this pic.. Then run T stat normally. Circ will run but boiler will not fire..

But I see in the pics that your boiler may not have a pilot setting on the gas valve. I see a seperate pilot valve.. So in that case turn the gas valve to off position. Pilot should remain lit AFAIK.


Make sure you drain exp tank completely.

As furd stated fill system to 28 psi. Then go bleed a rad or two.. Youll have to probably raise the psi several times during this process.

When your all done bleeding make sure you set the cold psi to 15..

Then lite pilot and fire her up..

Verify heat at the rads.

Also post how the rads are connected.. Are they in a loop or a mono flo tee system?
Attached Images  
Old 12-09-15, 02:48 PM
Thread Starter
Join Date: Dec 2015
Posts: 4
Received 0 Votes on 0 Posts
OK so my first instinct was correct about shutting off the gas. The gas valve is less than one year old and there is a gas shut off up the line and on the valve itself I can turn it to OFF.

The images are the supply and return to the radiator I will be moving and the radiator as it sits in the room, currently.

I will be draining the tank and boiler with instructions Ive read on this forum about opening the bleeder in the upper most/furthest away radiator and using a garden hose on the spout to the in floor drain.

Any more specifics of the tank or anything else you need or I should be aware of??
Name:  IMG_7594 [477298].jpg
Views: 912
Size:  35.5 KBName:  IMG_7595 [477299].jpg
Views: 929
Size:  39.5 KB
Old 12-10-15, 10:10 AM
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 718
Received 25 Votes on 20 Posts
Looks like you might have asbestos insulation on the pipes. The pipes near the expansion tank certainly look like it. Do not puncture the cover or mess with it yourself. Only a properly trained and licensed asbestos remover should do that work to protect your health and your property. Airborne asbestos fibers are practically invisible and are extremely dangerous to health!!!!!!!

If you do have asbestos it will probably not cost a lot more to have it all removed at the same time due to the setup costs and precautions that must be taken.

You can replace the insulation yourself later with Fiberglass pipe insulation. However there is one school of thought that insulating the pipes in an enclosed basement that is not insulated from the floor above is not necessary. Any heat radiating from the pipes in the basement will help heat the floor above.
Old 12-12-15, 05:40 AM
Thread Starter
Join Date: Dec 2015
Posts: 4
Received 0 Votes on 0 Posts
The reason for doing all of this is to remodel my kitchen, in doing so I needed new windows in that room which led to windows for the entire house. Yeah.... The silver lining is that one of the window installers is a contractor and plumber, he is tackling the moving of the gas and radiator lines on the side and he will be removing the insulation which IS asbestos. He doesnt do HVAC work however and the company that normally services my system wants a ridiculous amount of money to fill and bleed the system ($400-$600, estimated. $50 just to show up and $92/hr for however long it takes to bleed)

The only thing that is still odd to me is if I pressurize the system, after bleeding the lines, with the gas OFF, when I do fire up the boiler its going to expand well beyond the 30psi valve and blow off the excess, which is fine I guess. But to me if I got "close" knowing that my upstairs radiators will have air in them still and turn it on, it seems to be a more gradual approach to where I may not need to expel water out of the valve. Am I being clear? I know I will be adding water and bleeding repeatedly but it seems easier than having loads of hot water on my basement floor!
Old 12-12-15, 12:11 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
Fifty dollar minimum and $92 an hour is not a ridiculous price in my opinion. My local auto repair facility (owned by a tire company) charges $130 an hour for work done in their shop.

You CAN fill and bleed the system just as easily as can anyone else. Start with the expansion tank absolutely empty and you should have no problems with over pressurizing the system IF you follow the instructions I wrote out in the second post. With all the air removed, a minimal amount of water in the expansion tank and the pressure no higher than 15 psi cold you should not have a rise to any more than 25 psi at the highest UNLESS the expansion tank is woefully too small.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: