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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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We have a 100-w boiler and it has always been an issue

Customer Question

We have a 100-w boiler and it has always been an issue with room temperature. It does not seem to match up to what our room thermostats are asking for. i.e. it is 95 f outside and the thermostat in the room is turn down but the furnace is running heat into the room at the same time. What is wrong and how do we fix it?
Submitted: 2 years ago.
Category: HVAC
Customer: replied 2 years ago.
Not sure if this is working or not.
Expert:  Rick replied 2 years ago.
Do you have more than 1 thermostat? What brand boiler?
Customer: replied 2 years ago.
viessmann vitodens 100-W, hot water heating with 3 zones. same issue with all 3
Expert:  Rick replied 2 years ago.
How do you make hot water? do you have pumps/circulators or zone valves for zone control?
Customer: replied 2 years ago.
with have 4 zones, one is for the hot water, they all have zone values. there is one main circulator pump
Customer: replied 2 years ago.
do you have any experience with viessmann boilers?
Expert:  Rick replied 2 years ago.
Yes, but this sounds like a control issue which is beyond the abilities of most homeowners to fix. We can take this as far as you're able to troubleshoot if you want to try a fix yourself. If you do I need to know what brand zone valves you have and if you have a zone control or not
Customer: replied 2 years ago.
no, not a zone issue, is a viessmann boiler controler issue. has something to do with the way they work. please do no more work on this then. thanks.
Expert:  Rick replied 2 years ago.
Ok, but you have a fundamental misunderstanding about how these systems work
Expert:  Phil replied 2 years ago.
Hello, whenever a heating zone valve is open, the hot water pump runs, and that fires the boiler in heating mode. The problem is in with the zone control control module, or one of the thermostats. Let me know a lot about your technical skill sets and if you have a class 2 multi meter or not. If you do and wish to continue with trouble shooting assistance send me a close up well focused photo of the units wiring diagram (glued to the inside of the front cover), and several photo's of the zone controller with its door open, and a close up of the wiring diagram glued to the door, taken from straight on, and I will coach you on a diagnosis. It is tricky business, plan on 2 hours or longer. If none of this is in your bag of tricks, tell me which direction you are from the center of the nearest town or city and I will look for a Viessmann dealer for you... they are common in about 20% of north america, and a bit scarce in the rest of the region. You can use the paper clip icon to attach the picture if you like.
Customer: replied 2 years ago.
ok, there was a mis-understanding. i don't want anymore work done on this. or fees. thks