fitting an extra pump

[bonesy60]

Hi I have a snooker club with 14 600 by 2000 double rads running off a baxi combi boiler that keeps losing water through the blow off i am going to fit a second expansion vessel because I think that's the problem. I also have a problem with the one leg that has 9 rads on I can't get the heat to the last 3 no matter how much i balance the system. Now to the question can I put a second pump in and pull a cable back to the boiler so that they run together and should i put it on the flow or return many thanks.

 

[shaky]

How big is the boiler

 

[bonesy60]

Its a Baxi 80 E

 

[stevetheplumber]

boiler is under sized mate 14 x2000/600 doubles is about160000 btus you need another boiler

 

[bonesy60]

I agree that the boiler is to small but it is all i have to work with I have tried to tell him but he wont spend the money. But would that explain why the water wont reach the furthest rads, if they where luke warm then yes but they are stone cold.

 

[dontknowitall]

Possibly a bigger pump too and maybe cleaning out pipework and those last 3-4 radiators.

Sounds so simple sitting here in my arm chair. Bet it's not when you're stood there looking at the system.

 

[bonesy60]

If I close the leg that has5 rads on the 9 get hot so i wanted to fit an extra pump to move the water around the system this place has sixteen tables 4 wide 4 long so you can imagine the distances of pipework

 

[stevetheplumber]

if you try adding an extra pump dont wire it to the boiler it will fry the board due to the extra load on start up

 

[Deleted member 25704]

Adding an additional pump can causes problems.

Get to the root of the problem - undersized pipework? pump too small?

Contact the manufacturer - I have fitted additional pumps to all sorts of boilers, some vaillant boilers have an additional terminal on the board for pumps, so it is driven from the boiler board, so does not affect the other mechanics of the boiler. This boiler might have similar provision.

Also check the system is two-pipe - if its one pipe there could be problems - once went to a 10K refurb of a hotel heating system, but many of the rads failed to work - it was a simple as the rad valves which were used (not suitable for one-pipe systems, which require low resistance valves).

Other cheap knacks that may make a difference is over-dosing the chemical inhibitor - this reduces friction in the pipes and liquids improve velocity, thus compensating for undersized pipework. Or service the existing pump and check there are no blockages in the impellors and that it is running smoothly - grunfos can type pumps can be easily serviced by knocking out the can - contact manufacturer for full details.