COLD START vs WARM START

Rongold

Hi all,

I have a Weil McLain WGO6 boiler---NO tankless hot water coil. When the boiler was new, it came with a Honeywell 8148 control box which is a high limit only and circulator control. The installers recommended that I change the control box to a Honeywell 8124 control box that has a low limit function. I did that a few weeks after I got the boiler. Their reasoning was that the boiler would be much easier to clean if condensation never formed inside, and it would last longer as it would never cycle from dead cold to normal operating temperature. . They said that as the condensation dries, the soot becomes very hard, like cement, and is almost impossible to clean, while keeping it from getting cold would tend to eliminate leaks between the boiler sections. About a year after installing the 8124 box, the circulator relay began chattering, so I replaced it again----and again, and again. I went through about 4 of the 8124 boxes in 6 years due to chattering circulator relays. While I was going through the 8124 boxes, Honeywell came out with the 7224 control box. I figured it's function is the same, but it's electronic, all the relays are more modern, smaller, and enclosed in plastic, so I bought one and it has lasted for at least 12 years until my immersion well started to leak internally and liquid got into the 7224 box and it shorted out. I fixed that, and everything is back and working, but I see no reason to keep the boiler warm & running during the summer, except for the forming of condensation inside. Right now, I have the low limit set to 120 with a 20 degree differential which keeps the boiler temperature cycling between 100 & 120 degrees--just enough to keep condensation from forming. Should I keep it like this for the whole summer, or should I turn it off completely and run the risk of leaks between the sections and the risk of forming cement like soot inside, which would be extremely hard to clean ???

Thanks for your upcoming knowledge & opinions.


RON

STEVEusaPA

Well you’re going to get some vastly different opinions.
Looks like you had this boiler almost 20 years and you went thru 6/7 aquastats?
In 30+ years I’ve never replaced more than one on any boiler.
Chattering relays could’ve been caused by something else-bad low voltage wiring, high moisture/humidity in basement, weak/poor neutral, etc.
Once soot gets to rock hard, cement-like in a pin boiler, it’s usually done.
If the boiler is piped correctly you won’t need to worry about condensation. If not, a modern aquastat with a 'circulator hold off' would be a second line of defense to help prevent condensation.
Don’t underfire the boiler.
Then you could run it as cold start and not have any problems, like probably 10's of thousands of people currently do.

100-120 doesn’t prevent condensation. Only 140+ for oil.

I’d turn it off, see if it leaks. If it leaks, put it back on warm start and start saving for a properly sized, properly installed new boiler, like any triple pass or an EK.

Ctoilman

Your aquastat issue is not the fault of bad aquastats, there's some underlying issue somehow the 7224 overcame....but it's working nonetheless.
I think I'd try cold start on a Weil McLain because it doesn't have steel push rings that typically need heat to seal.
I have run my 33 yr old boiler for years as cold start but it has an indirect tank that calls enough to make the boiler stay warm.
Should you want the very best aquastat, next time install a Hydrostat 3250plus.