Taco check valve


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Old 03-18-05, 06:57 PM
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Taco check valve

Hi,I have an old dorad boiler originally for coal using a gas conversion burner with the circ pump at the return end,and sadly no zone valves.This is not used for domestic hot water.

As the water leaves the boiler,part of it loops to re-enter the boiler in front of the circ pump at a gate valve.Should this always be open?and the purpose for the return line?
The rest of the water continues upwards a few inches past the loop line to a very old taco check valve with 3 slider settings,open,closed,normal.Above this valve is the pipe in to my expansion tank.Now closed is obvious,and it has always been set to normal,is this correct?or should it be full open?I tried searching to find a similar one but it must be way to old.

Since last time I did some work a month ago and I am still bleeding air out of my lines since I did not refill it properly,where can I install an air scoop?


Thanks
 

Last edited by flyerfan; 03-18-05 at 06:58 PM. Reason: forgot
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Old 03-18-05, 07:27 PM
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Originally Posted by flyerfan
As the water leaves the boiler,part of it loops to re-enter the boiler in front of the circ pump at a gate valve.Should this always be open?and the purpose for the return line?
Yes the valve should be open & its purpose is to recirculate some of the hot water leaving the boiler back into the return. This helps to prevent "cold shock" to the boiler.

Originally Posted by flyerfan
The rest of the water continues upwards a few inches past the loop line to a very old taco check valve with 3 slider settings,open,closed,normal.Above this valve is the pipe in to my expansion tank.Now closed is obvious,and it has always been set to normal,is this correct?or should it be full open?I tried searching to find a similar one but it must be way to old.
"Normal" is the correct setting.

Originally Posted by flyerfan
Since last time I did some work a month ago and I am still bleeding air out of my lines since I did not refill it properly,where can I install an air scoop?
If you have a conventional expansion tank (one without a bladder), you do not want to install an air scoop.
 
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Old 03-18-05, 07:37 PM
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great thanks,I appreciate it.Out of curiosity since I do indeed have an old non bladder expansion tank,is there any other way except for just bleeding the 2 rads farthest away where the air settles?(i wound up with a lot of air in the system when i accidently snapped a bleeder off and did a rush repair )still bleeding every 3 days about 2 months after the work.


thanks
 
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Old 03-18-05, 07:43 PM
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Radiators

Radiators tend to trap air because of thier design. Something you might want to do is bump up the pressure on the system by a couple of pounds. This often helps to get the air out. With radiators an air scoop would likely be of little help anyway.
 
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Old 03-18-05, 07:54 PM
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K I will try that thanks,sorry used rads as a generic term they are like horizontal finned baseboards but about 5 times as wide,and higher off the floor and mounted in 2 1/2 foot high by about 6 feet long vented boxes, never seen them anywhere else yet,of course they are older than both of us put together.

thanks again
 
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Old 03-18-05, 08:08 PM
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Talking Older? I doubt it

Myself, I'm older than dirt. What you have are called convectors. Because of their box design, they work very well. That box acts like a chimney. Convectors too tend to trap air, just not as bad as radiators. With a bladder type tank, you could install automatic air bleeders on each convector.
 
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Old 03-19-05, 01:26 AM
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Check Valve

flyerfan:

I'm surprised you don't have an indirect hot water heater connected to your system to provide the domestic hot water; these units are a very efficient way of making hot water; you mean you have a separate gas or electric hot water tank?

Regarding the air problem; you should have gotten rid of the air within a week or so; fresh water added to the system will always have some entrained air in it; like Grady says, increasing the pressure slightly will drive the air out (usually to the radiator tops, where it can be vented).

There are 2 basic different ways air is handled in heating systems; the older, non-bladder expansion tanks are designed to "accumulate" air in the system & try to route it to the upper section of the expansion tank; I've seen a number of installs over the years that have an air scoop right after the check valve with a 1/2" copper line to the expansion tank to return any accumulated air to the top of the tank; this doesn't work so well when most of the convectors are ABOVE the expansion tank,(as they usually are when the expansion tank is in the cellar), because air tends to seek the highest point in the system; however, this might work in your case as the least costly thing to try first.

The other option, as Grady indicates is to install a bladder type (Extrol Model 30) expansion tank after the check valve & make sure all the convectors have a bleed valve installed; this is known as an "air elimination" air-handling system & is the 2nd way heating systems eliminate their air; the air scoop is still used, but instead of a copper pipe going to the expansion tank, a manual float-type bleed valve is installed in the top fitting of the scoop, the bladder-type expansion tank is connected to the bottom fitting of the scoop.

It's possible your system contains a lot more gallons of water than the more modern systems, which means you may need a larger than normal bladder expansion tank.
 
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Old 03-19-05, 09:17 AM
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Hi,yes a piece of **** rental from the gas company that combined with the rental conversion burner is killing me every 3 months when I get the bill.My unit does have a lot of water compared to many around here,each convector has an individual feed and an individual return line.I will look into the bladder exp.tanks thanks

Indirect hot water is unusual here ,so are boiler units.Most houses new and old are forced air.

What I have been waiting for is a need for some serious work to be needed before I start any drastic changes,or till the gas companies force the government to deem the conversion burners unsafe as they are trying(right now they refuse to repair any) they try to force the gullible to buy boilers off them.

Then go tankless for both(a friend installs these units in new houses now for cheaper than installing a new boiler)and they can handle the heavy usage.

My boiler now is 3 feet by 3 feet by 4 feet,plus a standard water tank,that is a lot of area to free up and just have it on the wall instead.Up here (southern Ontario)we have both good installers of them and an availability of parts... so seems to me the way to go.


Thanks
 
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Old 04-01-05, 06:16 PM
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follow up

Just a follow up here.I did increase the pressure as suggested.However I am still bleeding about 4 or 5 seconds of air out of the 2 convectors .They are the ones highest and furthest away from the boiler.

Since I also figured all the air should have been gone,would trying to drain my bladderless exp.tank(assuming it is water logged) help?Figured it is safer to ask first then to just jump and wind up doing something harmfull.


Thanks again....
 

Last edited by flyerfan; 04-01-05 at 06:17 PM. Reason: typos
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Old 04-02-05, 10:31 AM
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Air in System

I doubt draining the tank would solve the problem, but it wouldn't hurt anything; if the tank was "waterlogged" you'd be getting ~30 psi water pressure & the PRV valve opening & dumping water on the floor.

If you DO drain the tank, isolate the tank from the system by temporarily closing its shut-off valve & allow the tank to drain COMPLETELY before refilling.
 
 

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