# Draining & Filling Boilers



## mattd860 (Feb 24, 2011)

I really want to save some money with the install of my wood boiler to my oil boiler. I have plenty of plumbing experience (sweating pipe, etc) so I'm running all the copper between the two boilers, hooking up the new circulator, and a few other odds and ends. However, since I have NO experience with draining and filling a boiler, I wanted a plumber to make the tie-in's to my existing boiler for me and have him drain/fill/bleed the system. After all - we're still in the middle of winter and I have a wife and baby in the house....

With that said... I'm still thinking about making the tie-in's myself since it will save me about $400 bucks and looks easy to me. Adding the Tee's (tie-in's) to the existing piping is a no-brainer for me but how difficult is it to fill and bleed the system when I'm done?? Do I just open the air vent over the expansion tank???? Should I open the pressure blow off valve and maybe even the check valves too?? My worse fear is getting it all back together and getting air locked or something that prevents the system from re-heating the home!

Any advice will be greatly appreciated. I've provided some pictures below so you can get a better idea of what I'm working with.

*Burnham Boiler / Becket Burner*


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## coal boiler (Feb 26, 2011)

go on you tube under bodyshop18336 and see how i plumbed mine i have a d.s.boiler .excellant quality workmanship and just plain simple


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## Willman (Feb 26, 2011)

Can't really tell from your pics but if there are isolation valves on the supply and return lines by the boiler you can shut them down and just drain the boiler enough to tie into the existing pipe. Refill the boiler while venting air from the blow off valve and then you will have to open the side where the air scoop is and vent there. There might be some other venting spots you might be able to use depending on how it was piped.this leaves the return side to bleed. If you cant find any other bleed spots then you will have to open the return valve and keep trying to vent out the scoop vent. Looks rusty though you might need a new valve. I have loosened the air valve and bled from there on occasion. After all this you will have to bleed your baseboard closet to the boiler. Hopefully you have bleeders on those.

If there aren't valves on the boiler then all bets are off, the entire system will have to be drained. I would then put in ball valves for proper isolation. There are isolation ball valves with purge/drain ports in them that can be mounted with your circulator.This would, take care of purging the return side if you ever have to service again.

Will


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## mattd860 (Feb 27, 2011)

Drained the boiler, added the tie-ins for the new wood boiler, and filled it back up. It was cake! I even added a drain valve since there was non, a purge valve, larger expansion tank, and zone shutoff valves. Previously, there were only shutoff valves on the return of the zones, just above the circulators. 

I have a question about boiler pressure. Before I started the work, I noted the pressure was 30psi which is what the boiler has been operating at since I've owned the home (6 months). The boiler manual says to fill the boiler until 12psi and then it goes right into saying not to exceed the maximum psi as noted on the boiler nameplate. The boiler nameplate reads 50psi max. So I ended up filling it initially to 12psi as stated, purged the system, and then continued to fill it back to 30psi. After about 12 hours of operation, the boiler is still operating at 30psi so it's running normally. However, forgive the noob question - since the max is 50psi, should I increase psi higher than 30psi? Will there be any performance increase if I increase the operating psi?

Take a look at the pics:

*Boiler Pressure - Burnham V8 model W83 installed in 2006:*






*BEFORE*






*AFTER*





Pipe with 3-speed circulator sending return water wood boiler return (wood boiler located in garage)






Supply with check valve from wood boiler. Also note the purge valve.





New drain valve. I had to stick a wet-vac hose down the 1-1/2" return pipe to drain the boiler since this valve was not previously installed.


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## ohbie1 (Feb 27, 2011)

Amazing! I have the same oil burner & boiler.  My setup looks almost exactly like yours.   If you look at the tag on your pressure reducing valve, it will tell you what it's set at.  This is the min. pressure that the valve will keep your system at.  Mine is 12-15.  From what I have seen they are usually around 15 psi give or take a bit.  More pressure should not result in more efficiency.  I would think your safety pressure relief valve is rated around 30 psi. So if your system is pressurized above that, the safety valve should discharge until your sys. drops back below the discharge valve's rated pressure.


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## Willman (Feb 28, 2011)

Your gauge might be off or your PRV would be releasing the pressure. 28 or so pounds is about right. When boiler cools it goes a little lower. The pressure should not be raised. The way to lower it is with the fill valve. With a properly working x tank and water pressure at the fill valve set you should be fine running at 28-29 lbs. 30ish there should be a blow off. 

Decent piping job your on your way.

Will


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## Poodleheadmikey (Mar 1, 2011)

Boiler Fill Pressure - 

Water weighs one lb. for every 2.34 feet of height.

Or:  one lb. of water pressure will support a column of water 2.34 feet high.

What is the relief valve rating on this boiler?

Almost certainly 30 lbs working pressure is far too high.

You want the least pressure which will provide proper operation.

Measure in feet from the pressure gauge to the highest point of the hot water heating piping.

Divide that number of feet by 2.34.  This will give you the proper working pressure for your system.

Let's say that you measure and the height is 23.4 feet - so in that case you would need / want a boiler pressure showing on the pressure gauge of ten lbs.  Twelve lbs would be fine and allow something for gauge inaccuracy.

PHM
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				mattd860 said:
			
		

> I really want to save some money with the install of my wood boiler to my oil boiler. I have plenty of plumbing experience (sweating pipe, etc) so I'm running all the copper between the two boilers, hooking up the new circulator, and a few other odds and ends. However, since I have NO experience with draining and filling a boiler, I wanted a plumber to make the tie-in's to my existing boiler for me and have him drain/fill/bleed the system. After all - we're still in the middle of winter and I have a wife and baby in the house....
> 
> With that said... I'm still thinking about making the tie-in's myself since it will save me about $400 bucks and looks easy to me. Adding the Tee's (tie-in's) to the existing piping is a no-brainer for me but how difficult is it to fill and bleed the system when I'm done?? Do I just open the air vent over the expansion tank???? Should I open the pressure blow off valve and maybe even the check valves too?? My worse fear is getting it all back together and getting air locked or something that prevents the system from re-heating the home!
> 
> ...


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