Second pump on circuit

[Billy Bob Bob]

Having issues with 2 large designer rads i fitted taking a long time to heat up,did explain this to the custy from the word go but they want to know can anything be done,pipework is 15mm,fed off 22mm,Rads are proving to be too restrictive for the pump,too much resistance to get round,never done it but can a second pump be put on that circuit?-

 

[Scott_D]

What about less restrictive rad valves? one pipe type?

 

[Best]

^^That's what I was thinking, - the ordinary TRVs are too restrictive.
15mm coming direct from 22mm should be okay though.
Also think about balancing the rest of system really well, giving priority to the designer rads having full flow. Fit a pump, if it outside the boiler, that is more powerful and suits restrictive rads and pipes. A 6m pump, has actually more torque than a 5m and therefore more suitable on a small house that has microbore pipes or restrictive designer rads.
Make sure if any bypass valve or hot water cylinder, if fitted, that they aren't robbing the flow and derating the pumps ability. The pump will just miss the designer rads if it has an easier circuit

 

[ShaunCorbs]

open vent or sealed system?

 

[Chalked]

Two pumps in parrelel will cause all sorts of cross circulation. Could you fit a bigger capacity main pump? And ballance the rest of the system.

 

[Billy Bob Bob]

open vent or sealed system?

Sealed system,5 year old worcester heatslave ,system fully balanced ,no trv,s they wanted designer rad valves

 

[Best]

If the other rads are turned off, does the two designer rads heat up fairly well?
I find I have to turn all the other rads lockshield valves and any other balancing valves really well down to try to get some designer rads working reasonably well on some badly piped systems.
Some pumps partly fail and can't cope with any restrictive parts, or furthest parts of systems, but put heat around the rest of system well. Especially if magnetite in pump

 

[SimonG]

Not get a bigger pump on a heatslave. Can you fit an additional pump nearer the rads and use a pipe stat to switch on and off?

 

[ShaunCorbs]

as its sealed install a bigger primary pump and balance other rads a bit more

or if one cant remove and fit and external pump

 

[Destroyer2813]

Thats what you get for having yellow and red rads

 

[Billy Bob Bob]

If the other rads are turned off, does the two designer rads heat up fairly well?
I find I have to turn all the other rads lockshield valves and any other balancing valves really well down to try to get some designer rads working reasonably well on some badly piped systems.
Some pumps partly fail and can't cope with any restrictive parts, or furthest parts of systems, but put heat around the rest of system well. Especially if magnetite in pump

not much difference,they are still slow

 

[Billy Bob Bob]

Not get a bigger pump on a heatslave. Can you fit an additional pump nearer the rads and use a pipe stat to switch on and off?

Already a 6m in there,but thinking of going down this route

Thats what you get for having yellow and red rads

LOL the colors hurt my eyes