Second circulating pump, Flow or Return pipe.

[casaco]

Hi, we have a problem with a large property, 25 radiators, 2 x 29Kw boilers on a manifold, zoned into two areas, the radiators furthest away in master bedroom, about 30 meters, just not getting hot, all flushed out and clean, the pump on its own is not powerful enough, there are other radiators 20 meters in the opposite direction to master bedroom but that circuit is working fine. Which pipe would be best to install a second pump on.
My business partner who normally does the design work died in November, pneumonia, so I am on my own now, any helpful suggestions appreciated.

Thanks
casaco

 

[Howsie]

The pump may be fine if its been sized right. Try balancing it first. Google balance radiators and you'll have all the info you need.

 

[chris watkins]

Would need to see the layout of the existing system, any drawings ? What size pipework are we talking about, 58kW for 25 rads seems a bit overkill ? did the system stop working ?

 

[casaco]

Hi Chris, actually there could be more than 25 rads if you count the towel rails and there is a huge unvented cylinder, the owner wanted hot water fast and plenty of it, when you isolate one wing of the property, the other wing does heat up, i have tried balancing the rads but when both zones are open one wing cools down.
I know a second pump will solve the problem and I think the return pipe would be best, I was just wondering if that was the popular consensus.
Thanks for the reply.

 

[Whn1]

Surely if one zone is getting priority due to bad pipe lay out putting an extra pump on he return won't solve anything. Saying that it's hard to say without being here and seeing for myself.

 

[diamondgas]

Hi casaco

having an additional pump added adds complications IMHO ... Have you inherited the problem, new or old installation?

 

[dancinplumba]

why not put each boiler on each zone with their own pump

 

[Roger Welton]

What dancin says, I'd be thinking low loss header then separate pumps for each wing

 

[diamondgas]

What dancin says, I'd be thinking low loss header then separate pumps for each wing

Thought the same for each 'zone', but depends whether it's worth getting involved in in the first place eh?

 

[Howsie]

Hi Chris, actually there could be more than 25 rads if you count the towel rails and there is a huge unvented cylinder, the owner wanted hot water fast and plenty of it, when you isolate one wing of the property, the other wing does heat up, i have tried balancing the rads but when both zones are open one wing cools down.
I know a second pump will solve the problem and I think the return pipe would be best, I was just wondering if that was the popular consensus.
Thanks for the reply.

Why ask for advice when you ignore it?

 

[sgph]

Why ask for advice when you ignore it?

i thought that. also second pump at best would need fine balancing due to "starvation" of working zone!.
split system or re-pipe to suit.. IMHO TA steve

 

[Howsie]

There's a joke in this thread if you look hard enough...