Comparing Two Circulation Pumps: 25-60-180 vs 25-40-180 in Solid Fuel Boiler & Radiator Setup

Hello, I need help. The case looks like this: a solid fuel boiler. The installation is made of steel pipes. A year ago, an installation in the attic was added. Pump 25-60-180 for power supply. The new installation is inserted into the old one, about two meters from the boiler. Exit 5/4 ", then 40 plastic to the ceiling, 2 elbows 45 and passage to 32 to the manifold. From the pex 16 manifold in the floor to 8 radiators, aluminum Krakow aramatura. The installation was still air-tight, once a week it was necessary to vent the radiator and the radiators were hot, lower summer , very summer all along. This year I remodeled and put in a second pump 25-40-180 on a supply about 1.5 m from the manifold. The effect of the installation does not air, the radiators heats the entire surface the same. It is a fairy tale. When the pump is turned on, water overflows in the first and a little in the third radiator, looking from the supply side on the manifold, and some radiators on the lower floor heat up halfway from the top, as if the second pump took heat from the installation and gave everything up. The pumps are connected together with a cable controller - pump on the stove - pump at the manifold Both work on the 2nd range Where the cause of the problem Please help

Try to put the old pump on the 3rd gear, and the new pump on the 1st, maybe 2. Turn off those radiators where the water doesn't overflow and vent the noisy ones.

tryba_max wrote:

some radiators on the lower storey heat up to half of the top, as if the second pump was drawing heat from the installation and giving everything up.

Two pumps in circulation are like two mushrooms in borscht. You have reverse circuits on these heaters - you heat back up.

So how? Because I do not understand. The second pump causes the heater to heat back? But the returns are cold in those heaters

I understood? One pump is pushing water into the other? Pumps should be connected in parallel. Draw a diagram as it is with you.

Yes, one in the other, all in the description in 1 post

tryba_max wrote:

So how? Because I do not understand. The second pump causes the heater to heat back? But the returns are cold in those heaters

It was me who misinterpreted the quote I made - sorry. In these half-warm radiators the circulation is correct, but it may be that it is a bit too small in relation to the needs - it is too cold in the rooms, since you are writing about it.

Pump 2 for lower gear.