Will changing my pump setting affect the balancing of my radiators?

[CJCymru]

Sorry for being a newbie with little experience here. Next week, as soon as I've flushed my system to remove X400 I poured in the system last weekend, and refilling the system, I will then be rebalancing all the radiators in my house.

Today, while checking if my water pump needed venting, I noticed the pump was set quite high. It's a Grundfos Alpha2, and it was set on level 3. Does it need to be this high? My house is fairly small with 11 radiators. So I was thinking of dropping this to level 2 to save on the electric bills, or maybe even level 1!? Should I do this before balancing the radiators next week, or wait until after as it might affect the balancing?

 

[cross thread]

Was your system restricted ? Someone may of lifted the pump speed to overcome the issue, start on 1 with the pump

 

[JonathanM]

Do you know which mode it is in? There are three modes, fixed speed, constant pressure and proportional pressure.

 

[CJCymru]

Was your system restricted ? Someone may of lifted the pump speed to overcome the issue, start on 1 with the pump

We've only lived in the house since 2018, so have no idea. The balancing in the house seems awful, at least 2 radiators are mostly stone cold. It's been like this since we moved in. So perhaps the previous owners increased the pump speed due to the poor system balance, it's certainly a possibility. So I think I will try the pump on Speed 1 to begin with when I rebalance the system.

 

[CJCymru]

Do you know which mode it is in? There are three modes, fixed speed, constant pressure and proportional pressure.

According to the manual, it's set on constanst speed.

 

[Harry Bloomfield]

The balancing in the house seems awful, at least 2 radiators are mostly stone cold. It's been like this since we moved in. So perhaps the previous owners increased the pump speed due to the poor system balance, it's certainly a possibility. So I think I will try the pump on Speed 1 to begin with when I rebalance the system.

Before attempting to balance them, start by ensuring they are bled. Another possibility is that they are cooler due to a restriction in the flow to them, either an airlock, or other debris in the pipes or the actual radiators.

 

[Johntheo5]

We've only lived in the house since 2018, so have no idea. The balancing in the house seems awful, at least 2 radiators are mostly stone cold. It's been like this since we moved in. So perhaps the previous owners increased the pump speed due to the poor system balance, it's certainly a possibility. So I think I will try the pump on Speed 1 to begin with when I rebalance the system.

11 rads will probably require ~ 1m3/hr
speed 3 at 6.2M will give this flowrate at a 5.2M head, speed 2 (3.0M) 2.8M, forget speed 1 (1.0M)
Constant pressure CP 2 at 4.5M might be a good starting point and then just possibly either speed 2 above or Cp1 at 3M.
I have 10 rads that require 3.6M with all TRVs calling for full heat which my Wilo Yonos Pico supplies at a 4.7M PP (proportional pressure) setting.