Reconfigured some Radiators, is there anything I need to do to ensure they don't leak?
I picked up 3 Richmond radiators on Craigs List, but they were in sizes I didn't need, 1 3 column, 1, 4 column, and 1 13 column. So I took them apart and re-configured them. I still haven't bolted them back together yet. The next step for these is off to the powder coater. Before I do that I have three questions:
- How do I make sure that the push nipples are properly sealed?
- Can I use all thread instead of the tie rod that they came with as that's the wrong size now.
- How tight should I tighten the tie rods?
In Progress:
Final Result, 2 6 column rads and 1 8 column rad, I've not yet bolted them back together.
Comments
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Push nipples and their seats. Make sure they are completely clean and free of any scratches. They don't have to shine like fine silver, but… no visible or feelable scratches. Use your fingernails. Both the nipples and their seats.
Then, when powder coating, be absolutely certain that those seats — full depth — are completely clear of powder coat. If the radiator is disassembled, they must be carefully masked off and sealed.
Tie rods. You can certainly use threaded rod. No harm there, except it will be harder to keep clean down the road.
How tight? Do not use the tie rods to pull the sections together! Use pipe clamps or something of the sort, top and bottom, to evenly pull them together. Then thread the rods in, bring them up finger tight on clean threads cold, and then about a half turn of the nut. No more than that.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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Assemble the rads before powder-coating them. Then pressure-test them by filling them with water to 30 PSI. If they hold that pressure for 15 minutes they should be OK.
We like to use some red high-temp RTV silicone caulk on the push-nipples. This makes them go together more easily and, after it dries, helps to seal them.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting
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@Steamhead are you mentioning something like this? Or is there something else which would be better?
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That should work.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting0 -
We pressure test with air, a compressor, and a 5 psi gauge.
The problem with powder coating is the very high temperature, which sometimes can result in leaks. If you powder coat, test again afterwards before installing.
We prefer 2-part epoxy paint.
New England SteamWorks
Service, Installation, & Restoration of Steam Heating Systems
newenglandsteamworks.com
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I love powdercoat as a radiator finish but have experienced leaks on rads (both with threaded and push nipples) after the fact due to, I believe the high heat as others mentioned.
I have come to really appreciate DIY "bronzing" as an attractive, easy, inexpensive option that avoids that risk.
A few years ago I shortened a radiator with push nipples and utilized a bead of silicone on the inside boss of one of the mating sections. Essentially invisible after assembly. May not have been necessary but I am glad I did it- no leaks. Paint or bronzing afterwards would be an option here but powdercoating would not.Good luck!
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At Castrads, we test all of our new and refurbished radiators to 8 bar (115 psi) of pressure, on a water test.
Testing at these pressures provide peace of mind, knowing that the unit doesn't leak at well above standard operating pressures (25-30 psi on a hydronic system).
If this is a DIY job, I would recommend getting yourself one of these.
They are easy to use, other than a little effort pumping the lever, and, as mentioned, provide great peace of mind knowing that you're hooking up a radiator that doesn't leak, especially if it's a hot water radiator!
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We prefer using water rather than air. Since water is a non-compressible fluid, if something lets go there is much less chance of the broken piece flying through the air and hurting someone.
Also, 5 PSI might be OK for testing a steam radiator, but for hot-water 30 PSI is much better, This is the pressure at which the safety valve on a hot-water boiler will open.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting
1 -
I would do as you planned, leave the rads apart and have sections individually powder-coated being careful to protect the waterways from the process. Assemble the sections, hopefully you have access to an assembly tool specifically for cast rads like the Burnham #6054001, check with local supply houses as they sometimes offer them for rent. Use Loc-Tite #592 on the push nipples and of course pressure test before installing, as mentioned earlier if this is a water system test to 30psi., most water systems operate around 15-20psi.
PS - Watch your back and toes!!
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Another way to do a hydrostatic test on a pressure vessel is with a grease gun. Fill the vessel with water, install a zerk and pressure guage in some piping, then bring up the pressure to your desired test psi.
Don't get carried away. Grease guns can generate thousands of psi.
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When reassembling radiators its important to sand the ridge off the socket. I was taught to use plumbers cloth and polish the push nipple and socket until shiny, assemble dry, and tap together with a hammer on a hard wood block, never hit the cast iron with the hammer, be careful with alignment, and help pull gently with the rods and leave them the rods snug. I remember some casting defects leaking but never the push nipple joints. wafer test to 30 psi
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I recently took some large radiators installed in a (late 1800's) 5 family and reduced them to about 1/3 their original size, recalculated the heating load after adding spray foam and switching to thermal glazed windows, needless to say the original bolts were too big, and, being threaded on only the last 2", could not be cut down. I used threaded rod in their place, so I could cut to the exact size I needed; I polished the nipples best I could but ended up with some leaks… BUT… after one heating season the leaks disappeared; I am guessing the expansion and contraction of the CI, coupled with the tension on the bolts worked the sections back tightly together.
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Why wouldn't you just cut and tap the old rods to the new size?
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or buy steed rod cut and thread to the length you need.
You can buy brass or stainless rod also.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream2 -
Old school joint sealer I have used on push nipples and questionable threads. Is boiled linseed oil and Portland cement. Mixed to a brush able consistency. The oil allows slip , the Portland fills gaps and dries hard. Thoughts?
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