My steam boiler is short cycling, this weeks video

RayWohlfarth

This weeks video discusses how to know if the boiler is short cycling and if it is, the possible causes. Have a great weekend.

https://www.youtube.com/watch?v=x-MCpzNkrPE

Jamie Hall

Nice summary, @RayWohlfarth . Now if people will watch it…

RayWohlfarth

@Jamie Hall LOL thanks

MarkMurf

In the drawing, where's the Hartford loop? Was that a packaged boiler ? Is your boiler water priming and surging in yer gauge glass ? This prehaps causing that #67's float to join the dance ? How about the differential setting on your pressuretrol ? Too tight ? And are you blowing the boiler down quite often enough ? And that clogged control manifold ? Prehaps a blowdown valve on that would alleviate mineral build-up. And if your boiler water is priming and surging in the glass, some tri-sodium phosphate added to the boiler and a surface blow down would help. There are many different possible causes. And as with ANY steam boiler, "Without proper maintenance, there is no civilization !"

NickT

Excellent explanation, Ray! Simple and quick.

All lessons are highly appreciated. Thanks for sharing your experiences!!

RayWohlfarth

@MarkMurf Yes sir Maintenance reduces the chance of a boiler accident by almost 80% I appreciate your feedback

@NickT Appreciate the comments and feedback

Robert_T

Having worked on numerous 1 pipe and 2 pipe systems for over fifty years, I have found the biggest influencing factor with cycle length is the anticipator and its setting for longer or shorter cycles. I know most newer thermostats give you a one-size-fits-all with dip switches (no good) but it turns White Rodgers still makes stats with adjustable anticipators, and there is the good old Honeywell in the round too. Of course, the other points you mention can contribute as well, but I have found them to happen very rarely. I find it odd that the Master Houlihan doesn't even seem to ever mention this function. (haven't seen it anyway in his publications)

Bob Terry

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RayWohlfarth

@Robert_T I havent seen that as much as I work on commercial systems Thanks for your input

Ray

PEvans

A good summary.

I wish there was more on whether short-cycling is a big deal. For example, if the boiler is oversized, remedying that would major surgery. Is it best just to live with it? Or set the pressure control cut-out higher so the system gets closer to satisfying the thermostat on each cycle?

My steam system has two zone valves that divide the EDR roughly 2/3 (Zone 1) and 1/3 (Zone 2). So if the boiler is sized for both zones (3/3) on a very cold day, it is going to be way oversized to serve just Zone 2. At the low pressure settings we advocate here it is going to short cycle on Zone 2, and it does. Should I care?

RayWohlfarth

@PEvans You are limited with an on off residential burner. I have seen people try to convert the on off burner to two stage and haven't seen one I trust or that worked. Some of the older commercial atmospheric boilers used to use two gas trains. You have to be careful that the flue gases do not condense when underfiring a boiler. Perhaps a time delay relay will slow the cycling and delay the start of the boiler. You would have a longer run time. Good luck

Steamhead

https://forum.heatinghelp.com/discussion/comment/1857293#Comment_1857293

Most of us know this- but, here is what can happen when a boiler is not properly maintained. This video, starring @Gordo, shows a W-M LGB-5 that did not even have blowdowns on the low-water cutoffs:

https://www.youtube.com/watch?v=cNxF_XOv5HM

We're going back with a W-M 4-80 and a Carlin gas burner, and we will use probe-type LWCOs installed directly into the boiler sections. Both models have nearly the same ratings.

Side note- According to W-M's own published specs, the LGB-5 steamer has a water content of 28.9 gallons when filled to the waterline, whereas the 4-80 has 36. This means it's more forgiving.

RayWohlfarth

@Steamhead Great video Thanks