A new heating system was installed in my duplex.
Our main floor has a hot water 20 Kw Electric Hydra boiler and our second floor is only electric baseboards.
We originally had hot water oil furnace.
The problem is from our main floor with the hot water electric boiler. Every time it turns on there's this loud bang that comes from the pipes of the baseboards.
What can be the problem? Is this safe? We already called the technician.