Removing Cast Iron Radiator

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  #1  
Old 05-29-19, 03:26 PM
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Removing Cast Iron Radiator

Hey everyone,

First post here, super awesome site with lots of info. Looking forward to using it while we reno our house room by room. Ok, our issue, which I am pretty sure I know the answer too, but want to verify.

We have a hot water radiator system in our house with old cast iron radiators. We need to repair a wall behind the radiator and want to remove it for a short temporary time. Now, our system has one hot supply and one cold return going to one side of the house and another going to the other side of the house. They also go to the second floor of the house to supply the two upper bedrooms. Each radiator has one valve on the supply and nothing on the return pipe which is on the other side of the radiator. Yes, I will attach some photos.

Now, I have read that a lot of the old valves most likely will not turn off the water fully, which might be the case with this one as when we tried to turn it off during the winter at a fully turned position the radiator squealed which leads me to think that it does not fully close. Oh, and each radiator does NOT have an additional valve coming off the supply in the basement, just the one next to it on the supply.

Now with this situation I am thinking I need to turn off the main supply valve to the boiler, then begin to drain the system and open the bleed valve on the radiators from top to bottom until I reach the level of the subject radiator in order to remove it, would that sound correct?

Also, while it is off, would you recommend the valve for the room be replaced?

The other thing I am now concerned with is that I read the sticky about not flushing your system every year as to not introduce fresh water with more oxygen and minerals, so should I add inhibitor when I refill it and where should that be introduced?

Thanks in advance!

David and Daniela

(The photo of the back of the boiler, the pipe in the foreground is the cold return and on the bottom, the other side of the pump, is a drain valve)
 
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  #2  
Old 05-29-19, 03:39 PM
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Welcome to the forums.

I'm not the boiler pro.... they'll be by.

You don't want to make a routine of draining the boiler. It's ok to do when service is needed. You should assess the entire system to check for leaks and other things that may need to be replaced. Do them all at once.... especially when the heating system is down for the summer.

I wouldn't use any additive when refilling the boiler but it will take some time to purge all the air out. I'm not sure I'd change those valves. There really is no need for them to shut off completely during normal use. Make sure to have big wrenches to loosen those nuts. I use a 3' Crescent pipe wrench and sometimes a small sledgehammer to tap it. .
 
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Old 05-29-19, 04:07 PM
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Thanks for the welcome and reply!

Yeah, draining it often is not good, but our biggest problem is we need to live in the house at the same time so doing one room, maybe two at a time is the only option. Maybe the situation would warrant replacing the valves on all the radiators at the same time that way they work for sure and when it is refilled we would only need to eliminate one radiator from the system via valve in order to not drain the system. What do you think?

Also, how long do you guys think it takes to convert the new water to an inert state to reduce corrosion?
 
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Old 05-29-19, 04:14 PM
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You would not only need to replace the old valve..... you'd need to add one to the opposite end so that both sides could be shut off.

I'll let the boiler guys discuss the refill.
 
  #5  
Old 05-29-19, 07:49 PM
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DD,
From your pics it looks like a 2 pipe system which means all of your supply lines come off of 1 pipe and return in the other which would give you some options if you had valves on both sides. With that type of system the water feeds each rad individually so if one started to leak you could shut it off without loosing heat to the others and remove it if it had valves on both sides. The valve only on the supply side is good for shutting it off but not draining it.

To drain the system you can start by shutting the boiler feed off and then draining the boiler and the system will drain from the top, down. Eventually it will pull a vacuum and you will have to open some vents to introduce air so the water will continue to drain. Unfortunately there are no valves anywhere to make it easier.

I cannot tell from your pics but it looks like you have no isolation valves at all and it would be well worth installing some, even on the mains for future maintenance. For example, if you ever had to change your pump with no valves to isolate it you would have to drain the whole system again and on and on and on.

When they installed that near boiler piping with the new boiler they really skimped on things. You have no air elimination devices such as a Srirotherm Air eliminator which would take care of the bulk of the air being introduced with fresh water. They're depending on your rad vents to bleed everything which could be a long process.

Once you make your repairs and are ready to refill you will have some more questions I'm sure. As PJ mentioned, I would forget about chemicals in your case. You have an old system and chemicals would only loosen up anything that's in there and possibly create more leaks. In some cases rust is what's holding these pipes together.

If you decide to change the valve you have to change the piece in the rad also. It is a matched set and can be difficult. You've got a system you can do a lot with if you have any specific questions.

https://www.supplyhouse.com/Air-Eliminators-310000

Hope this helps a little.
 
  #6  
Old 05-30-19, 12:46 PM
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My advice would be to follow @Spotts recommendations, he is pretty much spot on (pardon the pun). If you decide to replace the radiator valves I would contract that out since it a tough job that requires the right tools, a good know-how, and a lot of swearing. One thing you may want to consider would be to replace the valves with or add thermostatic valves at each rad for individual room control. The same site referenced for the auto vent can supply these. Check for "Danfoss at the site or Google "Danfoss" for information. You could drain the system, remove all or most of the rads, and make all the repairs behind all the rads at 1 time so you do not have to drain the system numerous times. Just a thought.
 
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