Weil McLain with Model 1107-1 Integrated Boiler Controller Always On

waytoohot

I live in a 3rd floor apartment with a Weil McLain boiler in the basement that provides hot water for the kitchen and bathroom and the baseboard heating. The baseboard heater is permanently on and does not respond to the thermostat. (I set the round Honeywell thermostat below the 50 F mark and the baseboard heater temperature max and min values don't change at all.) I am monitoring the baseboard temperature with an accurate digital oven probe and can confirm the thermostat has no effect on the baseboard temperature cycles. On very cold days the apartment has a reasonable ambient temperature, but on warmer days the apartment is way too hot and we have to open the windows or kill the boiler power from the breaker unit. The landlord has made the following changes (at least) to try to fix the problem:

• replaced cartridge for the baseboard heater
• replaced the 3 way valve
• replaced the thermostat

Previously, I recall the round thermostat would have an audible click at the temperature when the commanded temperature exceed the measured ambient temperature and I don't hear it now with either the old or recently replaced thermostat.

Here are some photos of the boiler, including the control boards and wiring.

When the thermostat is "off"

The baseboard heaters still cycle continuously.

I'm hoping to expedite this process by posting on this forum. Any help would be appreciated. If there is any additional information or testing I can provide please let me know.

EdTheHeaterMan

Does each apartment have a thermostat? If yes, then your thermostat does not control the boiler control. your thermostat will control a zone valve or a zone pump. are there any other controls on the wall near the boiler or are that any valves on the pipes that have a motor attached to it with wires coming from that motor?

Your thermostat may not be connected to anything if there are no zone controls in the boiler room.

EBEBRATT-Ed

Could also be a bad flow check valve which would make the boiler over heat the house but it should still shut down.

waytoohot

@EdTheHeaterMan : Each apartment has its own boiler and thermostat. The boiler room in the basement is locked so I can't access it to check other details right now but can do so in the future. There is a pump on the boiler for the baseboard heating circulation and it was replaced several years ago. The previous one was under-specified and not circulating to the 3rd floor properly. I suppose what I care about is that I'm able to use the thermostat to change the baseboard heater temperature. Currently, the thermostat does not have any effect on the saw-tooth min and max values I'm measuring with my probe.

neilc

can you post a wide shot of the boiler, circulator(s), zonevalves(?), and any other control box(s), kinda all n one shot, or from a couple WIDE angles so we see it all in one veiw

HVACNUT

Its got a tankless coil and maintains a minimum temperature, so I would look at the 3 way valve again.

EdTheHeaterMan

It appears that you have the Weil McLain CGt boiler that is equipped with a tankless coil for DHW. Your statement that each apartment has it's own individual boiler that is operated by its own thermostat tells me that you have more than one boiler in the basement. Is that correct?

I can think of several problems that can be the reason for your problem.

• Your thermostat wire has been compromised and is completing the circuit as a result of a staple of nail that is connecting the wires together.
• Your thermostat is connected to the wrong boiler. That means that there is another apartment in your building that is too cold. They have the thermostat connected to your boiler set as high as they can go and are not getting any heat, while your thermostat is set as low as it can go and you are getting too much heat.
• A service technician was testing you boiler using a temporary jumper wire and forgot to remove it before leaving the job. That means that your thermostat is no longer in control of the circulator pump. Ti s just always on.

There are three possibilities. There are others a wider picture of your boiler that shows the connecting pipes and sires may be helpful.