Flushing out radiators

Koan

Had to remove a radiator to move some pipes to replace a joist. The water coming out was really dark and rusty. Does it make any sense to hook up a hose and try to rise it out, or is this a complete waste of time. What about flushing either the steam or return lines - is this ever a good thing? Thanks

Fred

A steam radiator shouldn't have much water in it. When you re-install it, make sure the radiator has some pitch towards the supply pipe (if this is a one pipe steam system) or towards the outlet side (if this is a 2 pipe system). While you have it loose, if it has a lot of crud/dirt in it, it is a good idea to hose it out. Also, the wet returns on the system should be flushed annually if at all possible. Mains should not need flushing.

Koan

@Fred wasn't much water in it. When I broke it loose about a quarter cup of clean water came out, then about a quarter cup of really rusty water came out when i tilted it toward the outlet (2 pipe). I'll flush it out. Sorry if this seems stupid, but by the mains do you mean the steam supply? when flushing the wet returns do I just hook up a hose and use the boiler blowdown or boiler drain valve? I apologize for my lack of knowledge.

Fred

@Koan , Yes, the mains are the larger steam supply pipes that feed steamto all of your radiators, by way of run-out pipes. Hopefully you have some drain valves at the end of the wet returns that you can hook a hose to and flush them out through another drain valve at the opposite end of the wet return(s). There will likely be a lot of crud in those pipes (below the boiler water line and you would be much better off using valves at the end of those lines (or having some installed at the ends) than to push all that crud into the boiler.

ChrisJ

Fred said:

A steam radiator shouldn't have much water in it. When you re-install it, make sure the radiator has some pitch towards the supply pipe (if this is a one pipe steam system) or towards the outlet side (if this is a 2 pipe system). While you have it loose, if it has a lot of crud/dirt in it, it is a good idea to hose it out. Also, the wet returns on the system should be flushed annually if at all possible. Mains should not need flushing.

My radiators all hold a good amount of water.
Some of them I'd say have close to a quart due to the design of the radiator and the fact they're bushed down.

Koan

@Fred Got it - thanks - Ill look for valves on the wet return prior to the boiler. If they don't exist I will work on putting them in. Really helpful - thank you!

vaporvac

If they're really clogged, does anyone here use a snake? I would think that might help with the hard mineralized debris.

Jamie Hall

vaporvac said:

If they're really clogged, does anyone here use a snake? I would think that might help with the hard mineralized debris.

Ye gods. I think if I ran into a wet return which was that clogged, I'd be mightily tempted to just replace the thing.

Koan

@Jamie Hall - the system is not clogged anywhere, but this summer we are thinking of removing the radiators, dipping and painting them. Figured that would be a good time to flush them out a bit as well as the wet returns.

Jamie Hall

Koan said:

@Jamie Hall - the system is not clogged anywhere, but this summer we are thinking of removing the radiators, dipping and painting them. Figured that would be a good time to flush them out a bit as well as the wet returns.

Why not, since you will have them out. Shouldn't hurt anything.

But while you are doing it -- don't forget that the unions between the valves or traps on the radiators and the runouts or feeds are matched -- don't go swapping radiators around from place to place!

Koan

good point. I will have to identify each somehow. maybe a small engraver and give each a number or letter.

STEAM DOCTOR

Careful with the wet returns. Flushing wet returns may expose leaks that were previously sealed with the sludge. Not saying that you shouldn't flush. Just be prepared to replace the returns.

Koan

Thank you @STEAM DOCTOR I did remove one radiator and the horizontal and vertical feeds had a little rust in them, like a dried brownish red powder, but nothing serious. The others might not be so well-off though.

Paul48

You might want to pressure test those radiators before you start the re-finishing process.

Koan

@Paul48 How much psi would you use??

Paul48

I'd use 10 psi. They won't see that in operation, obviously, but it will let you know if something is wrong.

Hap_Hazzard

Don't get too crazy about cleaning the inside of a radiator. The good thing about surface rust is that it protects the surface, because it can't oxidize any further.

I do think it's worthwhile to take out the bushings on any radiators that have them whenever you need to move them or replace the valve anyway. If you use a larger nipple and a larger valve and bush the bottom of the valve, there's less room for water to collect.

Koan

@Paul48 , @STEAM DOCTOR , @Hap_Hazzard, @Fred, @Fred, @Jamie Hall, @ChrisJ , @vaporvac :

Flushed all but one radiator in preparation for refinishing. Used a hose on the steam feed, and just let it run until clear. Didn't take very long. One larger radiator seemed to have a blockage... the water did not flow out at the force of the others and I could feel air back pressure when filling. I plugged the outlet and filled it completely then once full released the plug. After two times of this the filling back pressure was gone and the unit flowed well... a rust flake I assume. I repeated this on all the units and got more crud out of them. The trick was to use a conical nozzle on the inlet while plugging the outlet so air could escape around the feed...otherwise the air pressure keeps it from filling, but provided a simple low pressure test for any obvious leaks... none so far.

The remaining unit is 30 sections, 5 fins or Columns, 26" tall.
Still wondering how to move that one.

FLUSHING WET RETURNS:

NOTE: I see no valves on the wet return, and the only coupling joint is right against the floor. I think I have identified the wet return back up into the boiler - looks like a 2" pipe. Looks like I'd have to brake that pipe and put in two valves - one to prevent the crap from going back to the boiler and one to allow the crap to flow out through a hose. Otherwise I could try to undo the coupling on the floor and attach an adapter to a hose. I worry this would be messier as it would start flowing immediately.

Could someone please guide me on this if I attach some pictures? I have 3 floors of radiators removed so I assume now would be the time to flush the returns.

If the steam traps are still installed, will that prevent backflow or should I plug the lower returns while flushing the upper ones.

Would it be a good idea to remove the steam traps and cap the pipes not being flushed to prevent crud form backing up into the steam traps??

There are two large caps on each side of the boiler/furnace - they look like 3". I think there are the boiler clean outs.

Thanks to everyone!

Koan

@Fred @Fred trying to figure out where to flush the returns. I assume this is the pipe that runs along the floor then back up into the boiler. I also assume that vertical 2' plus pipe going back up to the boiler is where I want to install a ball valve so the crud does not go back up into the boiler, and a ball boiler drain to get the crud out??? Does that sound right?? I just want to make sure I don't flush the crud into a vent of a trap and screw things up.

Fred

The valves should be placed right at the bottom elbow at the bottom of that vertical pipe connects into the wet return (that pipe that runs along the floor) and another valve at the other end of that wet return, where it turns up and becomes your Hartford loop, at the boiler. Many older piping systems didn't have those flush valves so you may need to take the elbows off at each end of the wet return and replace them with Tee's and then add the valve into that Tee. I would but a ball valve in that Hartford loop as well to act as an isolation valve and keep junk out of the boiler when you are flushing the wet returns.

Koan

@Fred @Fred
I think I've got it. I understand the Hartford loop but not sure how to handle the Hoffman differential loop. Looks like the return piping is teed into it and don't want to force crud into it. Do I unscrew the bottom cap on the Hoffman loop as well?? I have some pics I can attach soon. Thanks!!!

Koan

@Fred @Fred
Attached pics showing Hartford loop and Hoffman Differential Loop. Trying to figure how to flush returns without sending crud back through differential loop. Looks like top of differential loop ties into return. Can I still valve off the vertical up to the Hartford loop and then put a drain valve at the base of the vertical?? thanks!!!

Fred

If you valve off the Hartford loop, you wont blow crud into that differential loop.

Koan

@Fred I'm really glad I read this thread over carefully, I was about to flush the system by running a hose into the returns from the radiator with the steam traps out. I read some diagrams to see that is NOT a wet return. So the only returns I will flush are the ones near the floor. I assume this is correct and I don't want to flush out the dry returns??

Fred

There is not likely to be anything in the dry returns. A lot of extra work for nothing. Just flush the wet returns (those that are below the water line of the boiler (may be at floor level or a few inches above the floor) and you should be good to go.

Koan

thanks Fred!

Jamie Hall

@Koan ,I have just looked at this thread in some detail. I see that you mention a Hoffman Differential Loop. May I contribute a few thoughts which have nothing to do with radiators -- but everything to do with that Loop.

First, you need a vapourstat. If you don't have one, get one. It should be set to a cutout no higher than 12 ounces, and probably less. Otherwise, the differential loop will trip and you will get no further heat in you system until things cool off.

Second, the steam mains must be vented into the dry returns through cross over traps. Do not add vents to the steam mains!
Cluster enough vents to vent your entire system at the top of the elbow, or just before it, where the dry return turns down to the differential loop. I repeat: there must be no other vents anywhere else on the system.

Your main vents noted above can be any you like, although Hoffman 75s are best (they reclose at a higher temperature than Gortons) but you would need more of them, as their capacity isn't anywhere near the big Gortons.

Koan

@Jamie Hall Thanks you Jamie for the input. We do have a vapourstat and it is set low, i'll check but I believe it to be less than 12oz. My concern right now is with the pigtails, so I will make sure they are not clogged. Also the mains are vented via two (or three - have to check ) crossovers to the dry returns for sure, then there is an additional main vent to a Gorton no2 right above the boiler at the Hoffman Differential Loop. No other vents are present. @Steamhead has examined the system recently, and worked on it in years past, so I feel confident he would have brought up any piping concerns.
Thanks for your input!!

Koan

@Jamie Hall here is a pic showing the Gorton 2 wrt the Hoffman Differential loop.

Fred

All is well if Steamhead has gone over it!

Koan

Now I see why the wet returns should be flushed each year. I figure the ones on this boiler were not done for about 45 years.

First, I tried to drain the boiler though the boiler drain. That valve would open allowing water to dribble through but would not close. It is toast. I got it out so I can put in a full port and a back up quarter turn boiler drain valve down stream.

In trying to make room for a flush valve and valve off the top of the Hartford loop I found the insides of the vertical Hartford loop pipe were nearly completely occluded. I have attached some pics of where the blockages are as noted in light blue on View One. Using a 3' Ridgid pipe wrench that i had to strike with a hand maul, I heated then removed the two 2&1/2 inch end caps (see View Two) and they were completely filled with crud bottom to top. The wet return from the Hartford loop back to the horizontal wet return was the same way, nearly completely clogged. Oddly enough the long run of the wet return looks to be fairly clear. I broke the 1&1/4 vertical pipe from the Hartford loop back down to the horizontal return header trying to move it enough to check for blockage, probably a good thing though as is was really stuffed up with crud. My real concern is horizontal the return header. Once I scored the broken threads of the 1& 1/4 pipe and heated the reducing tee and got the threads out I could reach in and see the 2" horizontal wet header pipe is half full of crap. I tried to undo the coupling to the right - it appears to be brass - but no joy. I got the two large union nuts to back off, but even with heating the coupling and twisting it with a 3' Ridgid I could not get it to budge.


Any advice on this following point is much appreciated.

My choices now are to try to use a drain snake though the 1&1/4 vertical hole in the reducing tee or to repipe the whole mess. I am thinking the drain snake to start. I will try to clean the horizontal wet header by using a 2 to 2 &1/4 " dowel from the opposite side (right) to fill the left cap area going back to the boiler, then snake out the left section and rinse, then reverse. I want to keep as much of this crap out of the boiler as possible.

Note this boiler is from the late 60's or early 70's so i get that it won't last forever. I understand in trying to clean this out I may expose or create leaks in the piping or in the boiler itself. I get that I may have brought this to a slightly earlier demise just by trying to drain the boiler. I'll try to gently clean it out and reassemble. If it leaks then at least I will know that it is time for the new Slant Fin that @Steamhead is recommending once this American Standard gives up the ghost.

Thanks All

Fred

Snake it out and then run a hose and flush it. After that, try to flush it annually until the boiler needs to be replaced. At that time, replace the wet returns too.

Koan

forgot the pics - sorry

Koan

@Fred @Fred Sounds like good advice!!!!

Koan

@Fred Can the 1&1/4 valve blocking off the top of the Hartford loop be brass?? Should I use stainless or bronze instead or does it not really matter?

Fred

Brass is fine!

Koan

Cool beans. I think I've got it now. Thanks @Fred

Koan

@Sailah , @Fred , @Jamie Hall, @STEAM DOCTOR, @vaporvac , @Steamhead, @ChrisJ, @Hap_Hazzard, @Paul48

Reinstalling ten painted radiators now, waiting to do the 30 section one - guessing it weighs 850 lbs and the re finisher would not dip it because it's too heavy.

They look great - will attach pics next time.

After flushing the radiators I thought it would be a good idea to flush the wet returns and the then the boiler.
I put in a coupe flush valves, and a plug for the wet return on the floor in case it had to be snaked (it was oddly completely clear).

I made a manifold out of PVC that let the water go through the horizontal near-boiler return but not back into the boiler. The PVC fits snugly into 2-1/2 " opening and I pushed it all the way through.

I ran a snake through the near - boiler horizontal wet return. I flushed it out with the make -up feed over and over but still a lot of stuff there. I made a Gerry Gill water wand but used 3/8 tubing and 120 psi street pressure (before the PRV) so I could guide it around turn in the 2-1/2 " tee and got tons of garbage out of the pipe. Just in case I put gate valves on both the Hartford loop and Hoffman differential loop and replaced all the other clogged plumbing in the blue line in the earlier pic.

I used the same wand to flush out the boiler itself ( another ton of crap out) and the new boiler drain flows well. The old boiler drain barely dribbled and once opened disintegrated.

All the pros must be in pretty good shape because this is arduous work. I had to thread four pipes by hand. Taping , doping, counting turns on each joint takes a lot longer than one might think.

I replaced all the steam trap guts on my Hoffman 18 radiator vents. I am replacing the two crossover traps (one Hoffman 18, one Barnes and Jones 122) with new Barnes and Jones BJ 2RC s vents - thank you @Sailah

I re-piped the vaporstat and gauge as both pigtails were closing up.

Once the crossovers are in and the remaining radiators are in place (this week) I'll light the pilot and fire it up with a Steamaster tablet or two. With any luck by this weekend I will finally have heat.

Thank you all for your guidance in dealing with this. I am so grateful to everyone here for helping me learn about this.

Fred

Wow @Koan ! You have been busy! I'm glad you have it all done in time for this heating season. You should see a lot of improvement in system operation and you should be proud of yourself for taking it all on and saving this steam system.

Koan

Thanks @Fred - I appreciate the encouragement!