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Jerry, HVAC Technician
Category: HVAC
Satisfied Customers: 422
Experience:  Epa universal certification, hearth products specialized.
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O am installing a new 242F without utilising the solar panel

Customer Question

O am installing a new 242F without utilising the solar panel yet and it will only run on "test". In normal run mode it doesn't run the pumps.
I have joined the two temperature sensors for the solar system side by side but still no joy.
I wondered if it would benefit form an in house temperature sensor?
Submitted: 4 years ago.
Category: HVAC
Expert:  JamesI replied 4 years ago.
Hi my name is James,

So I understand correctly your installing a Viessmann 242F heating solution, but the pumps wont run, is this correct?

Which pumps are not running the central heating pump to circulate the water, or the solar pump to circulate the heated water?

Can you advise what the Vitotronic 200 control unit is showing on the display?

Assuming this is a Central Heating pump failing to run, its most likely due to the control unit not being wired\programmed correctly, or because there isnt a heat source in place, otherwise you could be in a position where the pump is starting but the water it is pumping around is cooler than the ambient temp.
Customer: replied 4 years ago.

The pump that circulates the hot or heated water into the tank does not run and has no water in it (removing the central pump plug shows it to be dry) . The pump for the central heating is also not running. However it works in "test" mode but gradually the water gets too hot and it trips out.

Expert:  JamesI replied 4 years ago.
Right, why isnt the system pressurised?

There should be one pump circulating water, this takes water from the heat source (solar or boiler) and pumps it around the entire system.

You then have valves which will open and close parts of the system has they demand heat, so the radiators only come on when the thermostat or timer is activated, and the hot water tank only heats water when required (to stop overheating for example).

Have you installed this yourself, or has part of the work been done by someone else, also is this a green field install or an upgrade?