New Home - First Time With Oil Heating

ThatRadDad

Hi y'all.

I just bought a new home back in July. The heating unit was fairly new, so I didn't have real concerns with it. Now? I have some concerns with it.

I've never had oil heating before, so this is all new to me. I have a Slant/Fin Intrepid model TR-30HP. The biggest issues I have are:

1. One of the 3 zone thermostats in my house just doesn't function. Pretty sure that's just an issue with the face plate - when I swap one out, the other functions normally.
2. The boiler keeps tripping on high temperature.

I plan to call the service company tomorrow to have a technician come out and look at it, but I just wanted to make sure I wasn't missing something really dumb.

Thanks.

LRCCBJ

That boiler has a fixed output of 104,000 BTU/hr.

Since you most likely do not have sufficient radiation in the house to dispense 104,000 BTU/hr, the boiler will climb in temperature until it reaches what we refer to as "high limit". This is typically set at 180F for most residential buildings that have no additional control. At that point, the boiler shuts down until the boiler temperature falls to either 170F or 160F (depending on the control setting). The, it starts back up again and slowly climbs back to 180F.

When the thermostat reaches the setpoint, it opens and the entire heating process ends immediately until the thermostat calls again.

You can limit this behavior significantly if you set the Hydrostat "high limit differential" to 30F. The boiler will fall to 150F until it restarts again. Its cycles will be longer and the number of cycles in a given day will be less. You would need to ensure the "economy" feature is turned off to achieve this setting.

Jamie Hall

A boiler cutting out on high temperature (I presume it starts up again after a while?) is simply because the system can't take heat away from it as fast as the boiler makes it.

Now why that would happen… that's a good question. The first question is how is the boiler sized in relation to the heating system its powering? (Before someone yells about building heat loss and boiler size, yeah, I know. But if it is cycling on the boiler high temperature limit, rather than the thermostat being satisfied, it's not the boiler vs. the building, it's the boiler vs. the installed radiation). One can understand this as the only way that heat can be removed from the boiler (to prevent it tripping on high limit) is to move that heat and release it into the building — and if the boiler is oversize relative to the radiation it can't do that.

The next question is what is the water flow rate through the boiler? Again, if there isn't enough water flowing through the boiler, it can't get rid of the heat it is creating. Now there are two principle ways to pipe a boiler: direct through, in which all the water goes through the boiler and then out to the system and comes back, or primary/secondary, in which there is one loop which goes out of the boiler and around and back, and the rest of the system takes hot water from that loop, runs it through the system, and then puts it back into the loop.

The cure for tripping on high limit, if there is one, is going to depend on how your system is piped — so perhaps a few pictures from further back showing the piping and valves and pumps so we can see where the water is going would help.

ThatRadDad

https://forum.heatinghelp.com/discussion/comment/1816505#Comment_1816505

Thanks, Jamie. You've definitely given me some things to think about. We do have water flow issues with this house (don't get me started…). It does start back up after a while - it's just not getting anywhere near the thermostat temperature. I'll snap a few more pictures.

Could the problem potentially be this thermostat that's malfunctioning? It's piped to go to the 3 different zones, but obviously with this thermostat malfunction - there are 3 different baseboards that aren't getting the heat. I thought about this originally, but again, this is my first experience with oil heating, and I don't necessarily know what "normal" looks like yet.

ThatRadDad

https://forum.heatinghelp.com/discussion/comment/1816504#Comment_1816504

Thanks. This was one of my first thoughts. The malfunctioning thermostat isn't letting the heat get out to 3 baseboards, severely limiting the heat removal. I did make sure the economy setting is turned off, though.

pecmsg

where is this house located? Finding good honest contractors is difficult at best

ThatRadDad

Hopefully these help!

ThatRadDad

Slight update to the situation:

I found a way to make the malfunctioning thermostat work. It at least allows heat to those baseboards now. I also switched over to our well, which provides a lot more pressure than our spring-fed system.

I got similar results. It kicks on, heats until the switch hits 180F, then kicks off. From what I've read - this can sometimes be normal? Especially for a cold start? The house is probably about 55F right now and I just turned it up to 64F, for perspective.

EdTheHeaterMan

What does a typical radiator look like? Pictures please

HVACNUT

On top (side on yours) of the Hydrostat where the lights are is a button. Each press of the button shows a setting. High limit, low limit, economy, etc. What are the settings?

What provides domestic hot water?

ThatRadDad

Thanks for the help everyone! Turns out, all it needed was some time to warm up. Everything is running smoothly now. Appreciate it again.

PC7060

Recommend you a look at the buildup around the pressure relief valve on the boiler. Looks like a possible bad valve (leaky)

Post a picture of the valve from 12” or so so we can get a better idea of the situation.