Hydronic Heating and DHW

Bosun7

I have Triple AQUASTAT relay L8124A Honeywell controller on my hydronic heating boiler. It is setup like this for hot water heater as well. I don't have use it for hot water, I have electric hot water heater. How do I stop it from running the boiler to keep the temp for the hot water. I only want it running to provide heating and operate by room thermostat, by not for hot water.
If I turned down the low to 120 or whatever the lowest is, and Diff as well lowest set, will it eliminated the DHW coil? How it will affect on heating?

Could I, some how, bypass the Lo limit or disconnect wire from sensor?


Can you advise? Thanks!

GBart

Depending on the boiler, more specifics are needed, some boilers do well as cold start, for others it could be the kiss of death, a boiler is a tank of water, when it goes cold it will condensate and could cause rot and blockage of flue passages which could also lead to CO poisoning.

Leave the low low and be happy.

STEVEusaPA

If you leave the low limit turned all the way down, the boiler will still fire to maintain about 100°. I don't recommend a homeowner making any modifications to a safety control.
Better would be to swap it out with a newer electronic aquastat that holds the circulator off when the boiler temp is below 135° (and gives you LWCO). Then you could have cold start and boiler protection for cold water returning to boiler. Hardly any condensation problems.

GBart

STEVEusaPA said:

If you leave the low limit turned all the way down, the boiler will still fire to maintain about 100°. I don't recommend a homeowner making any modifications to a safety control.
Better would be to swap it out with a newer electronic aquastat that holds the circulator off when the boiler temp is below 135° (and gives you LWCO). Then you could have cold start and boiler protection for cold water returning to boiler. Hardly any condensation problems.

something like this

https://hydrolevel.com/fuel-smart-hydrostat-3200-plus3250-plus/

HVACNUT

Are you sure it's not an Aquabooster?
Is there a tan (or green motor with a stainless housing) circulator piped between the coil and electric water heater?

Bosun7

No, it's not Aquabooster, it's L8124A Honeywell, boiler is oil fired. I need some how to keep it run for about one month, till I will make infloor hydronic heating with electric boiler.
Boiler have coil insert for hot water heating, what if I will simple cut this coil and plug it? Will it work just for heating?
And if I cut hot water coil, should I disconect any wire from L8124?

Bosun7

GBart , I'm not at home now, can't tell you exactly what kind of boiler. It's cast iron, oil fired. I will be at home by end of next week, and can tell you model.
Thanks

Tom_133

There is directions on how to do this on this forum, I have done it a couple times in the past. You may need to use the search bar or google it and it may bring up the post.

GBart

For 1 month??? Just turn the low limit down and forgettaboutit. If you are ditching this boiler in 1 month you aren't going to save a dime, you'll burn more fuel from a cold start.

STEVEusaPA

If you're getting rid of the boiler completely in a month, just turn the low limit all the way down, it will still maintain temp of about 100°.

You're not suppose to leave the coil in the boiler, cut and plug both pipes. You have to leave one open to the atmosphere, or remove the entire plate, cut the coil off, replace plate (probably new gasket), then plug both holes.

Yes there is a way to modify your control so you can leave the low limit at 130° to hold the circulator and make the control a cold start. However, I don't believe in modifying a UL listed safety device, because now all the liability is on you.

Replace the aquastat with the one mentioned earlier. If you change the well too you get LWCO.

Bosun7

O boy... It's looks for me so..o.o complicated with this boiler and a lot of headache for me. I probably will sleep in sleeping bag, working fast for install new in floor hydronic system with electric boiler, and use some time fireplace for keep house little warm.
Any way thanks for help guys.

HVACNUT

> @Bosun7 said:
> O boy... It's looks for me so..o.o complicated with this boiler and a lot of headache for me. I probably will sleep in sleeping bag, working fast for install new in floor hydronic system with electric boiler, and use some time fireplace for keep house little warm.
> Any way thanks for help guys.

Why?
Do what @GBart and @STEVEusaPA said. Set the low side all the way down, and raise the differential all the way. Even lower the high to 140 if you're looking to save BIG bucks.

Still do the sleeping bag and fire though. Roast some weenies, cook up a pot o beans and...MmmmmS'mores.