Planning on replacing tankless coil in WM 468V boiler

Dave P

Hi,
I am thinking about replacing the tankless coil in my weil mclean 468V boiler. The reasoning for this is that I need to install a mixing valve (there never was one there, apparently) and also it seems to be leaking slowly around the bottom of the flange area.

I had planned on just replacing the gasket, but the supply guy told me they only have a replacement kit which has everything and is only $130.

So I just unbolt this, slide it out, and slide the new one in, right? Of course I will be shutting down and draining the boiler and unsoldering all the fittings first.
Is there anything else I need to look out for? I guess I could install union connectors and just install my valve for now, but it doesn't look too difficult to me ...

Al Letellier

coil replacement

Why replace the coil? The 68 isn't that old a series boiler and the coil gasket should be readily available. I thing your supply guy wants to sell a coil. If the coil is producing ok and you have no other operational problems, you can just replace the gasket. If you can't find one, make one. A piece of red rubber sheet gasket can be purchased anywhere and is easy to cut into shape....You've got the process right...be careful and replace the gasket if the flange is OK. Use some never-seize on the bolts and a thin coat on the gasket for easier removal next time.

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Dave P

aquastat settings

I decided to wait till the spring to tackle this job. Thanks for the reply, AL. My main concern is breaking the sensor (bulb?) for the aquastat. Anyway this leads to another related question:

After reading posts from this group and watching the temperature guage on my boiler, I noticed that they seem out of whack. The aquastat is a L8124C with settings of Hi-180, low-160, Diff-10. When I watch the temp guage I see the boiler on from 200-210 when there is a call for heat, and on from 170-180 when DHW runs. Seems like everything is off by 20 degrees.

My plan is to change to Hi-160, Low-140, Diff-20, and see how that runs. Should be safe as I am moving down in temp, right?

heatmakersheating Alton NH

chances of breaking the bulb are slim, breaking the coil bolts is more of a problem. stick with 160-180 on the aquastat 15 diff is good too.

Mark Wolff

Thermometer

The boiler temp/pressure gauge could be off. I would trust the triple aquastat relay more than the gauge. 160/180 with a 10 or 15 degree differential is fine. Don't be too concerned about it seeming to run hot. If you really want to know, you could replace the temp/pressure gauge, or use a laser thermometer to verify the actual temp (flat black spray paint works on copper pipe to get an accurate reading).

Al Letellier

Gauge

I agree with the post about the gauge being off. I love Weil Boilers but the gauges they used on that series were poor at best. Trust the aquastat and change the gauge when you drain the boiler to replace the coil gasket.

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Bob Gagnon plumbing and heating

did you try

to just tighten the bolts? bob

bob young

snapped studs

that would be way too simple. if you are doing this operation in the winter,better get a drill & tap ready and a new set of studs.