Burner will not shutoff

mike4478

Hello,
I have a strange issue with my heating system (hot water heating system from natural gas). My burner will not shut-off even when the guage is showing 200F. The starting pressure is 20 PSI in the guage and it rises to 30 PSI as the burner keeps going to 200F. The controls is through Honeywell Aquastat Relay L8148E. The system shuts down when thermostat turn-off heat or if I manually turn it off. There is no clicking sound from the Aquastat to turn off the burner.

My 2nd floor neighbor has exact same unit and is installed next to mine. Their burner stops when the guage shows temperature reaching around 140F and the pump continues to run.
I would greatly appreciate any suggestion or guidance.
Thanks
Mike

EBEBRATT-Ed

Shut the power down and take the cover off the L4184E and look for the high limit adjustment. It should be set in the 180-190 degree area. If you start the boiler and the burner is running and you turn this setting down below the water temperature in the boiler the burner should shutdown.

If it does not shut down kill the power and call for service. Do not leave it run unattended.

You cold also have a defective pressure/temperature gauge

mike4478

Thank you EBEBRATT-ED for your response.
I reduced the high limit to 190 but still burner is not shutting off. Do you think it could be a bad sensing bulb issue?

EBEBRATT-Ed

@mike4478

Turn the thermostat up so the boiler will run. While it is running turn the high limit control down and see if it shuts the boiler off. It should.

The temp it shuts off at shoud be the same as the temp on the boilers thermometer (within 10 degrees or so is ok)

mike4478

@EBEBRATT-Ed
I did what you suggested. I lowered the high limit control to 180 degrees and the burner shuts off when the guage is showing around 180 degreed with pump running. However, the burner is kicking back on within 30-45 seconds. The burners runs for another 3-4 minutes and then turns off and kicks back again within 30-45 seconds.

EBEBRATT-Ed

@mike4478

You posted that the boiler shuts down when the thermostat is satisfied and you also proved that the high limit works.

So we have to define the problem.

Is the house not heating or heating poorly?

Is it just that you notice the boiler cycling on & off?

Is all your radiation close to being as hot as the supply pipe leaving the boiler?

Circulating pump running?

What is the boiler pressure?

could be air bound radiation if thy are cold or lukewarm

What type of thermostat do you have?

mike4478

@EBEBRATT-Ed
First of all thank you so much for helping me with this.
Correct, that the boiler shuts down when the thermostat is satisfied and the burner turns-off when the guage reaches the same temperature as set on the high limit switch (180 degrees).
I am concerned about the boiler cycling on & off constantly. The burner kicks-in within 30-45 seconds even when the water is still hot (180 degrees showing in the guage). The burner should kick-in after about 30 minutes until after the water temperature goes down to 170 or 160? The controls are through Honeywell Aquastat Relay L8148E which I wonder is faulty.
The house heating fine when the boiler is running. And the radiators in the house are hot.
The circulating pump is running.
The pressure in the guage is 20PSI but it rises to 30PSI when the temperature rises to 180 degrees and then when I turnoff the system it goes back to 20 PSI.
I have Hunter programmable thermostat model 44155C
I hope I answered all the questions.
Attached are the images of the guage (before and after).