New boiler on gravity system
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
Comments
-
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.
0 -
separate hot water heater
0 -
ok thanks will get some pictures when I get home from work
1 -
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?
0 -
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.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
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
0 -
Yes it’s a gas hot water heater. My boiler is oil fired
0 -
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.
1 -
In your case the circulator should not be running when the thermostat is not calling for heat
2 -
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.
1 -
0 -
yes it does have this feature thanks
0 -
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
0 -
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.
0 -
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.
0 -
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
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
yes he put valves on the returns and risers
0 -
where would the purger be located? It doesn’t fire from a cold start the low setting on aqua stat is 130.
0 -
an air purger would be best right at the boiler on the supply piping. For best heat transfer in the boiler, and in the radiators you want a completely air free system, micro bubbles and big bubbles.
Most often the boiler fires only when a thermostat call for heat. It would drop to room temperature if it is off for periods of time.
If it is running all the time, maintaining 130f, you may be wasting some fuel dollars up the flue.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
I bet he is using the boiler aquastat as a low limit to help prevent the boiler from condensing. Not ideal but it will help. Thats better than nothing.
That may also explain the ghost flow out to the system and the overheating… especially w/ the cast iron rads.
1 -
what would be ideal to prevent condensing?
0 -
are either of these air purgers?
0 -
the brass on the left is your backflow prevention and reduced pressure fill valve,
the brass on the right is an auto air vent, let us see how it's piped to that riser, where it should be piped on the top where that cap is, the boiler itself has a baffle under there and sends air up that riser,
let's see a wider view floor to ceiling showing circs, another air sep might be hiding
known to beat dead horses0
Categories
- All Categories
- 86.6K THE MAIN WALL
- 3.1K A-C, Heat Pumps & Refrigeration
- 54 Biomass
- 423 Carbon Monoxide Awareness
- 100 Chimneys & Flues
- 2K Domestic Hot Water
- 5.6K Gas Heating
- 101 Geothermal
- 158 Indoor-Air Quality
- 3.5K Oil Heating
- 66 Pipe Deterioration
- 934 Plumbing
- 6.2K Radiant Heating
- 384 Solar
- 15.2K Strictly Steam
- 3.3K Thermostats and Controls
- 54 Water Quality
- 43 Industry Classes
- 48 Job Opportunities
- 17 Recall Announcements