EFM Gasket replace process / thoughts

Hey gents,
Figured I'd make a thread for this on it's own in case anyone else comes up with this type of question. For pictures of what I was working with see the end of this thread
VanWert VA600 to an EFM 520 install

After talking to Scrapper, he's going to be sending me another gasket as it seems to have stumped him as well. Maybe with the combined knowledge here some others my have some ideas. On my EFM 520 DF, new gasket and new rebuild by Scrapper Jr, ran for a month without a hitch, then the gasket started weeping from bolts and mainly along the bottom.. It actually sat full of cold water for 2.5 weeks before firing with about 14 PSI and didn't leak a drop. I have an autofill with a backflow preventer valve by the way. Anyway, I read the forums and everyone said you have to snug them up when new so I had tightened it up, but it seems to stop or start again. Scrapper told me to keep tightening every day and see what happens. He said normally they can weep a bit during the summer when they're cold etc., but it seems like its happening when the boiler temp swings during heat calls. It's not all the time either for whatever reason. I've been tightening, and tightening, one day I think hey it stopped, next nope. Not sure if I'm missing something or if I should completely cool it down, drain it a bit, loosen and readjust the current gasket, or just replace. At least it looks like the nuts and washer are brass or something cause they shine bright yellow under the black paint Makes it easy to not seize in the future I think?

In case it's a settings thing for whatever reason, my hydrostat is on eco level 1, temp set to 160 and I see swings down to 140 on a indirect DHW call or aux heat call. Typically it runs between 160-172, but highest I've seen it up to is 190 after a garden tub bath by the wife. 5 teeth / 4 air really can get the "freight train" rolling when you put a long hard call on it like a garden bathtub. I have a bypass pipe installed and the valve in it is 3/4 open.

Unless anyone has any other thoughts, I guess the next step is to drain it down a bit and loosen things up and see what's up? If you all think that's best, do you have to actually shut the fire off or can I turn everything off, drain it down to below the gasket level, take care of business, then just fill it back up and let it fire since it'll hold fire a long time? I don't have a DHW coil in it, just a block off plate and the gasket since I have an indirect.

Thinking I should have had Scrapper just weld a plate over it but never thought about asking him to do it. Standard way he said it to use a block off plate when not using a coil. Other than that, I sure do love the EFM, it's a heating monster when it needs to be. I haven't put my covers on it because it's nice having warm floors.

Thanks all!
Mike

Rob R. wrote: ↑

Sun. Dec. 12, 2021 2:26 pm

Although you can do this work without losing a fire, I think it would be easier with the boiler at a workable temperature. I suggest shutting the boiler down and letting it cool to <120 degrees before taking anything apart.

If you get it apart and don't see anything amiss, I would suspect the leak is though the threads of the studs or something else you can't see with the naked eye. If it were mine I would skim coat the sealing surfaces with "The Right Stuff" RTV and also put a dab at the base of each stud before you slide the gasket over and put everything back together.

If you want some insurance, you could also add something like this before you put the boiler back into service: https://s3.amazonaws.com/s3.supplyhouse.com/manua ... D_FILE.pdf

Thanks Rob!
Would you skim coat both blocking plate and boiler head, making circles around each hole and stud? Then I can put an extra dab at the base of each stud. I'm going to take your advice and use the boiler sealant anyway cause I like the idea of the insurance just in case no matter what.

Thanks,
Mike

So with this nice weather, I went ahead and shutdown the EFM and switched back over the modcon propane boiler for hot water. Yesterday, I cut power to it at 6:30am and I was shocked it still a very small fire at 12 still. My draft at the rear is typically .04-.05 without firing so this may contribute to it. I was was very surprised how long it took to actually go out, maybe I don't need a timer except for summer? I have the Honeywell Mercury time, but the longest setting is 30 minutes.

I let everything cool down to about 120 before I started to get to work. I have valves on both supply and return sides of the boiler to isolate it, and incase anyone wonders, it takes like 20-25 gallons to get it to drop below the DHW coil line on a full boiled . I was emptying it into 5 gallon buckets since I was curious.

I will post some pictures tomorrow when I can pull them off my phone, but taking the plate and gasket off was easy due to not being rusted, nuts had never seize on them, and the gasket was soft. I'm thinking the original gasket may have not been seated quite right or pinched on the studs. I found there were a few weld spatters on the boiler head under the gasket, and a "rough" spot that all may have contributed to it leaking. It wasn't leaking much and it was only occasionally. There were days it didn't then it did. It seemed to leak if the temp of the boiler was drew down too much.

So to fix what I thought the problems were, I started with a dremel on the couple weld spatters. They cleaned up really nice doing it this way. Figured it was safe using a dremel without risking a gouge or messing up a stud. I then took some 500 grit followed by 1200 grit metal sand paper to all the mounting surfaces the gasket would be touching. This made everything really shine and smooth. I used alcohol on everything to clean it all up before I moved onto RTV. Following your advice Rob, I used RTV on both the boiler head, block off plate, plenty around the stud bases, and even the holes around the studs in the backing plate. I put a real thin coat on everything with a putty knife first, then I did the traditional bead like you would any other gasket, connecting it all. I did this on both the plate and boiler head. I didn't want to take any chances figuring this would take care of the anything I may have missed. I've use this stuff a lot in the past on other projects and I wonder if it would seal it all on it's own without the EFM gasket. Then I put on the new gasket from Scrapper Jr, squished it all back together with fresh never seize on the nuts, and using X patterns to tighten, I torqued the bolts to about 10-12lbs. I let it sit to cure for 24 hours and filled it normal boiler pressure this afternoon. The verdict is that so far so good with no leaks that I can see and that was 7 hours ago. Tomorrow we'll fire up again and hope for the best as I really hated to turn the propane back on, even if it was just for DHW.

Old gasket New gasket As you can see - I spared none of the RTV. So knock on wood, I hasn't leaked a drop since the new gasket + RTV. I did not put the boiler liquid in yet as I wanted to wait and see after firing and a few days passed. I may end up returning the bottle to Lowes at this point.

I've seen it swing from 140 - 195 without issue so I'm pretty confident that the issue is taken care of!

Your going to need to snug the nuts up every now and then. Boilers breathe and work the gasket. Just give them a little tweak, after a week, then a month, then a few months. Don't overtighten, just snug them to where you did originally.

coaledsweat wrote: ↑

Mon. Dec. 20, 2021 1:35 pm

Your going to need to snug the nuts up every now and then. Boilers breathe and work the gasket. Just give them a little tweak, after a week, then a month, then a few months. Don't overtighten, just snug them to where you did originally.

Yep, I figured I'd leave it alone for now and keep an eye on it. If I see it weep I'll snug them up. I wonder if the rtv will make it less likely to need to be snugged up? Anyway, I'm keeping my covers off for now to watch it, but so far no issues! I've been itching to put them on since they're pretty blue and brand new.

I also followed Rob's lead and dropped my temps down to 150 from my 160 since the hydrostat can always push higher if it needs.

Why would you wait until it weeps to snug it?

coaledsweat wrote: ↑

Wed. Dec. 22, 2021 7:27 am

Why would you wait until it weeps to snug it?

Ah - I thought the idea was in general it would weep anyway and you just need to snug them up. My mistake on that one - so snug them up anyway I was worried about breaking seals already made..

Idea is to wait a few days to let it go through temperature swings. It expands and contracts slightly. Then you snug them up. I waited about a week on mine and then checked them a month later. Haven't really touched them since that second time.