Which one has no negative pressure water supply equipment?

Li San claims to be the first person to do negative pressure, and the technology is so advanced, but now there are too many people who can do this, and there is no technical threshold for a long time, they can do it! ! Pandas also say that their products are good, but there are many negative news on the Internet. I wonder what it's like.

Our company used a set of Qingdao Lisan in several buildings here in Wuhan, but it was not used later, mainly because it was not cost-effective. I have also used Shanghai Carrier and Chengdu Hongye, and the operation is stable without any problems. As for which is good, the following points are for reference:

First, it has strong enterprise strength. Now many manual workshops and OEM production have no negative pressure, so they must not be used.

The second is to look at the after-sales service ability.

The third is to look at local performance, and there are some hard qualifications, such as national inspection exemption.

That's about it. I hope I can help you.