New boiler on gravity system

jakamini

Hello my old boiler from the 30s I think finally died. I now have a crown boiler with a circulator pump and aqua stat with high and low settings. The way everything is set up now is overheating my house. The low setting on the aqua stat is set at 125 so every time the water reaches that temperature the boiler fires for about 5 minutes. The circulating pump is always on. My thermostat is set at 60 right now and the house temperature by the end of the day reaches 70-72. I have to turn off the boiler switch every night so we are not roasting in bed. I have cast iron radiators that hold heat very well. I have 2 questions 1 should the pump always be on or is it only supposed to be on when the thermostat calls for heat. The other is should I just turn off the low setting on the aquastat so the water is only heating when the thermostat calls for heat. The aqua stat is a hydrostat 3250 plus. Thanks for any info

jesmed1

Where does your hot water for kitchen sink and bathroom come from? It sounds like you have a domestic hot water coil installed in the boiler, which would explain the 125 minimum aquastat setting.

But your circulator shouldn't be running all the time. It should only be running when the thermostat calls for heat.

jakamini

separate hot water heater

PeteA

@jakamini

some picture from around your system is really helpful. Make sure to get enough pictures to show all the way around the boiler and the controls and piping, should be about 4-6 photos standing back 4-5 feet from boiler.

jakamini

ok thanks will get some pictures when I get home from work

jesmed1

Are you sure the "separate" water heater has its own heat source (like gas or electric) and isn't an "indirect" tank that gets heated water from the boiler?

Jamie Hall

Whatever the hot water source — the thermostat should turn the circulator on and off. It shouldn't be on all the time. And the aquastat will turn the boiler on and off as needed.

Something isn't wired up properly.

jakamini

ok the plumber temporarily wired it so I would have heat. Electrician should be coming tomorrow to install a new wire from the shut off switch and I will have him check all wiring

jakamini

Yes it’s a gas hot water heater. My boiler is oil fired

Kaos

Check if your boiler controls allow for a heat purge after shutdown, if not the electrician can add an off programmable off delay timer. You want to keep the pump on until the boiler cools down after each firing, this gets you a couple % of extra efficiency for free.

EBEBRATT-Ed

In your case the circulator should not be running when the thermostat is not calling for heat

mattmia2

Did you call the person that installed it? They might have missed a few things while they were trying to get the heat back on like setting it as cold start. Note that on a converted gravity system, unless it has a flow check at the boiler, if it is set up warm start it is very likely to heat the system through gravity flow even if the circulator isn't running. Set the low setting to not fire the boiler.

jakamini

jakamini

https://forum.heatinghelp.com/discussion/comment/1841800#Comment_1841800

yes it does have this feature thanks

jakamini

https://forum.heatinghelp.com/discussion/comment/1841815#Comment_1841815

I will call him tomorrow morning thanks. I was thinking the same thing. Between the pump going and the boiler firing so often I’m burning a ton of fuel

kcopp

That not the way I would have gone about piping that system.

Typically you try to mimic the flow rate. That looks like a 0010 on the piping.

Im not even sure there is any boiler protection there.

Systems Help Center - In category Hot-Water Heating

mattmia2

https://forum.heatinghelp.com/discussion/comment/1842113#Comment_1842113

i think i see a bypass in the back left. nice to have balancing valves between the mains, can't see if those are there or not. piping is probably bigger than it needs to be.

hot_rod

I don’t see any air purger? Also have him support the expansion tank a bit more.

When it fires from a cold start, time how long it takes to get the return to the boiler to 130F. You want that to happen within 10 minutes, ideally