boiler cycling for hot water loop - bad?

skimmer

We all know short cycling is bad for steam boilers.

What about cycling for a basement hot water loop?

It seems on my steam boiler, it cycles off and on to 180 much more frequently and with shorter run times when calling for heat only on the hot water zone.

I can hear it off and on many many times in an hour before the basement tstat is satisified.

Does this shorten the life of the boiler? Contribute to holes above the water line?

LRCCBJ

The hot water zone is tiny. The boiler is huge.

To limit the cycling you need an aquastat with an adjustable differential. If you allow the boiler to drop 30°F before it restarts, you'll cut the cycling by 2/3.

skimmer

Would that affect the heating?

LRCCBJ

Presuming it IS a steam boiler, it would NOT affect the heating. The boiler operates for CH via, typically, the thermostat, which will allow the boiler to actually BOIL. The aquastat does not.

skimmer

yes its steam with a hot water loop. honeywell aquastat with bulb inserted into boiler (not strap on) set to 180. any recommendations for the adjustable.. its wired into the 24 volt

LRCCBJ

This is a typical adjustable.

https://www.supplyhouse.com/Resideo-L4006A2007-High-or-Low-Limit-Aquastat-100-240-DegreeF-range-5-30-DegreeF-Adj-Differential-L4006A2007

The only question is whether the bulb will fit in the piping that you have. Cannot be sure without removing the existing aquastat. You can usually return it if it won't fit and you repackage it carefully as new.

LRCCBJ

You really should look carefully at the existing aquastat or get a model number. It might already have an adjustable differential!

skimmer

I will!!! I looked at the one at supply house, where would the differential be? I dont see it? is it a setting on the inside?

Jamie Hall

As has been said, this is a control issue. It is unlikely in the winter that the boiler will be too cold for the loop to work, but in any event there should be an aquastat to turn it on it it is too cold. Say at around 140 F or thereabouts. And that one — or another — should remove the demand for hot water at around 180 — but that one should not be wired to prevent the boiler from steaming in response to the thermostat.

Pretty simple really.

And, by the way, we don't all accept that short cycling is bad for steam boilers. It depends on just how short the "on' cycle is — and more particularly, how short the "off' cycle is. But that's another topic.

bburd

I think in this case that the cure in the form of spending money on a new aquastat is worse than the disease in the form of additional cycling. Some things just are not worth worrying about. If I owned it I would look to increase the differential if the existing aquastat is adjustable; the adjustment would be inside the cover.

skimmer

Well right now its set for 180. Its the only one.

It only cycles a lot when the basement loop calls for heat and the rest of the house (steam) doesnt. Which is usually on warmer days.

On colder days, when its running for steam upstairs, there is a main that runs thru the basement and helps keep it warm. And also since the boiler is running for steam, the water is generally hotter then 180 anyway if the basement should call for heat after the steaming cycle

EBEBRATT-Ed

Take the cover off the aqustat and look in the middle at the bottom under the wiring terminals. If it has the adj. differential you will see a white wheel with #s on it.

Or post the model # and we can look it up.

It will be a L4006A or a similar #

LRCCBJ

Here you go…………..

https://www.ebay.com/itm/305931833935?_skw=L4006A2007&itmmeta=01JG85WC9SR16QWNSYHWJYX2MA&hash=item473af5524f:g:WKkAAOSwoARnQ9et&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKl9iurg5w1GLaC0lGhk%2F4NeLym4BksKuItFQ5j9akn%2B0ZxG35Gnp5MFbG7LA%2B6FVug%2Fj5T1E3lcOquz0W3o%2BqMMpHQZEsX6I1XL0wXaRYa3F7bZ%2FYvlXHRACcQf6Q4YkE8AckWV--Pj0IC7haeF928Fx5OvnpAfuCIQ08h95uYi2u4nz1qMXnFFshR8lm7V3CNKjzjjJWxknTbIA7%2BOZrkXZISOtTz%2BYYpd1VFAyDRwg9W7UyjL%2B4JpawDOkItnYnIBpC6DtKbjOT0Nc%2BoxJQkY%2Bz7aAv%2BsXdwJk9ifY1uwHA%3D%3D%7Ctkp%3ABk9SR5jF8YWCZQ

skimmer

I dont see a differential wheel. Only a temp setting wheel??

LRCCBJ

The differential wheel is inside the housing. Need to take off the cover. What's the model number of yours? Should be inside the cover.

skimmer

Hard to get to at the moment.. Will check soon and post back.. thanks for the advice and help!

EBEBRATT-Ed

Honeywell L4006A2007 at Supply House.com is what you need.

Or similar model with adjustable differential.

Since it is not used as a safety high limit I would try E-Bay. Might be less $$$$ that Supply House.

skimmer

do you think it will make a difference? I don’t want to over think this.

skimmer

low and behold it does have a setback. It was set to 5 on the dial.

So I changed it to 30

so at the moment. It’s 180 with a differential of 30. That should cut back on the frequent off and on cycling for the basement loop.

It was getting excessive

Jamie Hall

That would have done it…

LRCCBJ

That's a home run. Nothing to purchase……………two minutes of labor👍️

skimmer

yeah really im glad i didnt jump the gun and purchase one..

i wonder how much this save on wear and tear and efficiency