i need to add another pump to my heating circuit to raise pressure in my system. So far everything works fine. I do not have a buffer vessel so my second pump is installed after the 3-way valve after the hydro unit.
I realized power supply via B7/B8 and a contactor so the second pump only runs when the primary one is running.
Now i need to shut off the second pump when the 3-way valve is in DHW mode. I have the B15/B17 connections that normally powers the 3 way valve (on my board the 3-way valve is connected somewhere else via a plug). Can i use the B15/B17 or B15/B18 connections to power a small standard contactor? The manual says the maximum current is 22mA. I do not want to ruin my controller.
Firstly, a belated welcome to the community, and sorry that nobody has given you a quick response.
I can’t advise anything electrical myself (not qualified), but I have found the Samsung UK Helpdesk to be very helpful with controller connections.
I suggest that you fire off an email to [email protected] explaining exactly what you are trying to do, and you should get a reliable response in a few days.
My contact there is Nick Kirwan.
Good luck, and if you get a response in a form that might be useful to other Samsung owners, please post it on the forum.
PS It sounds like you are effectively putting two pumps in series, something that can have unintended consequences (e.g. flow instability). Are you happy that you have all the angles covered?
Possibly, but I would not guarantee it - because the contactor or power relay would be a nasty inductive load. Much safer (for your Heat Pump) would be an optically isolated solid state relay, something like this:
You need to check that the pump will draw more than the minimum load current required by the relay, which is under Technische Daten: Minimum Load Current (Laststrom min) 150 mA. If the pump draws less current than this, it will not work properly.