I have a question concerning my hot water boiler/radiator system. I have a leak in a gasket on one of the lines just past the pump. I believe the pipes in the basement here are 2-3″ cast iron. Assuming I can get the bolts loose, would I have any problem repairing this myself? Is there anything to look out for (besides draining the system first!). As always, your thoughts and expertise are appreciated.
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You are talking about a circulator flange gasket, if I have it right.
You might have to clean up the flange surfaces to get a good seal. You would also need to know how to purge the system of air after repairing it. Otherwise, it is a very straight forward repair.
Edited 9/30/2004 4:28 pm ET by csnow
I googled "circulator flange gasket". That sure looks correct.
I know how to bleed the system of air. Would I need to put anything like permatex on the gasket? or does it go on dry?
We used "Neverseeze" for almost all gasket stuff when working a power plant in Greenland for DOD. I love the stuff.
I know how to bleed the system of air. Would I need to put anything like permatex on the gasket? or does it go on dry?
If the surfaces are nice and flat, I think dry is fine. If they are a bit rough, I like Permatex Aviation-form-a gasket or Hercules Block (similar chemically, but thicker- better for this application).
Thanks for the info to all. I plan on breaking into this over the weekend. It's a tight spot, but still accessible. I'll let you know if I run into problems.
If the gasket is constructed of metal with insulation in concentric rings, they can only be used once. Once the gasket has been compressed, it cannot be reused. These gaskets are sometimes called by the brand name Flexatalic.
When installing a gasket between flanges, it's important to draw the flanges together in parallel. After inserting the gasket, tighten all the bolts finger tight. Then tighten bolts in sequence going to the opposite side, not around in a circle. For example, if you had 4 bolts you'd do 1 then 3 then 2 then 4. If you had 8 it would be 1, 5, 3, 7, 2, 6, 4, 8. Tighten just a little at a time, drawing up the flanges evenly. If the gasket is one of the metal ones described above you should only turn each nut one flat (that is, one face of the nut or 1/6 rotation) at a time, then go on to the next (opposite) nut.
Man, talk about your time warp. I haven't heard that term - flexitallic - since leaving the USN sub service 24 years ago. Even at the nuke plant they were not referred to as such. Thanks for the blast from the past.
Incidently, there is usually a rubber gasket in the Taco circ flanges, though I have also seen flat gasket material (like Garlock) in some cases where the flanges are flat-faced instead of grooved for the rubber gasket.
I never met a tool I didn't like!
Wow. I left the Navy 20 years ago (1200 psi superheated steam boilers, 70,000 hp engines). That's where I learned the term. Do civilians call them something else?
Flexitallic is a brand name for a particular type of what you're talking about, which is technically called a "spiral wound gasket". It's made from a vee-shaped strip of thin metal (stainless steel or others) sandwiched with a strip of filler material (expanded graphite, Teflon, ceramic fibre etc.) of about the same width, and either spot welded and wrapped around a form or wrapped around an inner ring. There's usually an outer ring to hold the whole thing together too.
I was in operations, but worked with the maintenance dept quite a bit. They only referred to them as gaskets, but to be honest, in the 15 years I worked the nuke plant, I can remember seeing a flex on a job just a few times; though I spent a lot of my latter days in the control room, so who knows. Most of the valves are welded in to minimize leakage, those that aren't were in LP systems were flex's aren't appropriate. Pumps were also welded into the system. A lot of machined surface seating torqued to some serious specs. The philosophy was to weld it and forget it.
If maintenance was required and the equipment needed to come out, there was plenty of space and qualified people to do it. No flanges equates to fewer leaks, except for the through-wall variety, which I know plenty about; I got blown out of the turbine bldg Dec 31, 1991, 1631 in the pm. A drain pump line to the suction of the feed pumps blew, destroying the second line with it. Quarter of a million gallons of water got dumped in the building sump, not including all the steam that went out the vents at the top of the bldg. Blew two 4160/480 volt transformer/load centers as I ran by. Got in the CR just in time to tell them to dump it. I became the "expert" on erosion/corrosion. My wife still has the shirt I wore that day, sealed in plastic. I was about 25 feet directly below the two lines that ruptured. Got covered with all kinds of neat stuff.
I changed my occupation a few years later.
I never met a tool I didn't like!
How about automotive gasket sealer in a tube? I used some blue stuff from an aouto parts store on a hot water boiler circulator and it worked quite well.
Al Mollitor, Sharon MA
Are you suggesting I use it WITH the gasket or INSTEAD of the gasket?
As I recall, the seats for the gasket on my boiler were slightly pitted and I couldn't get a good seal with the cardboard-like gasket, so I used the form-a-gasket stuff without the fiber gasket. I let it cure overnight before I turned the water back on.
This was 3 years ago and the circulator seals are due to wear out any day now, so I may have more current experience to refer to soon!
Al Mollitor, Sharon, MA