Do i need anouther pump

[maxhat]

Hi

Boiler: glow worm 30cxi combi condensing.
Rads: 7
Pipe: 60 meters

The boiler is located in the loft, drops to the first floor to feed 3 rads, all fine, drops to the grond floor 3 rads 2 heat up fine the other heats up but takes alot longer, drops to cellar 1 rad takes about 1 1/2 hrs to heat up.

All valves are working and so is the pump.

The maximum water content is 130 litres for my system then it says in the book to fit an additional expansion vessel, don't know how to work out how many litres are in the system.

Do I need to fit an additional pump or expansion vessel to heat up the lower radiators quicker?

Max

 

[ratonnastick]

Was the system correctly balanced when the boiler was put in ?

Your symptoms sound like a badly balance system or a blockage.

Also From what i read these boilers will only work at there best if the flow and return temp is right.

 

[ratonnastick]

uhm

 

[croydoncorgi]

Sounds like you need to calculate the 'apparent' static head created by the height between your boiler and the radiator right down in the cellar. Problem is probably that the pump is fighting against the different densities of hot and cold water - and losing. Water will take the path of least resistance so instead of going to the bottom it's finding its way back to the boiler via the rads on intermediate floors. Try turning all the other rads off for a while and see if there is then enough pump power to heat up the bottom rad in a reasonable time. Once it's warmed up, the flow should go like a rocket!

If this works, then it's worth trying to re-balance the system by restricting flow to the upper rads.

 

[wilhelm]

how about increasing sealed system base pressure? or check it?
i know fkk all about sealed sysyems , does it show
awaiting.. to be ridiculed..
educate me.... thats what its all about..go lite on the sarcasm though

 

[croydoncorgi]

Aha - a masochist awaiting ritual humiliation. I'm unfortunately a sadist - so won't help!

Hint: System pressure has absolutely NOTHING to do with how far a system will pump DOWN. With a boiler in a cellar and radiators 4 floors above, 1 Bar would be JUST insufficient pressure to push water to the top of the system. The radiators there would have no water in, so would not work! 1 Bar is equivalent to about 32 feet of static head.

 

[wilhelm]

mmmm points noted, thanks

 

[maxhat]

Sounds like you need to calculate the 'apparent' static head created by the height between your boiler and the radiator right down in the cellar. Problem is probably that the pump is fighting against the different densities of hot and cold water - and losing. Water will take the path of least resistance so instead of going to the bottom it's finding its way back to the boiler via the rads on intermediate floors. Try turning all the other rads off for a while and see if there is then enough pump power to heat up the bottom rad in a reasonable time. Once it's warmed up, the flow should go like a rocket!

If this works, then it's worth trying to re-balance the system by restricting flow to the upper rads.

I switched all other rads off and it got hot in minutes, how do I balance the system??

 

[kevplumb]

get two pipe thermometers and close the locksheilds till you get a 9deg drop across all the rads very slow process

 

[brezzer]

get two pipe thermometers and close the locksheilds till you get a 9deg drop across all the rads very slow process

11deg drop that is

 

[kevplumb]

11 deg across the boiler di~~head not exactly subtle i know