Back boiler pump direction

[Corkplumber]

Had to replace an old circulating pump today for a back boiler. Before I removed the pump i checked the direction it was pumping by looking at the arrow.
It later occurred to me what if the pump was already out? How would you work out what way to put in a new one? How would you know which way to point the arrow?

 

[Irish]

You'd have to trace the pipework back to the cylinder and then work it out from the zone valves

 

[GQuigley67]

what if the system didnt have any zone valves ??? I just ripped out a back boiler system with no zone valves, had 1" primaries to cylinder and the pump was on the return from the heating circuit which then went into a Tee where the secondary from the cylinder joined in

I generally don't know the answer but there was 100% no zone valves

 

[Michaelskite]

normally have the pump on the return pumping into the boiler

 

[Mrjo2thec]

It can go on the flow facing away from the boiler but only after the open vent (and usually after cold feed) but obviously before the valve/s. Not too close to feed or it will pull air in. It can also go last on the return facing the boiler. it should work either way. Alot of back boilers have it facing the boiler but not all. You can determine the flow and return by looking in the manufacurers instructions or the pipe that gets hottest first etc.on gravity hot water systems (no zone valves etc) the pump was more often fitted to the return pipe with arrow facing the boiler.

 

[GQuigley67]

how did you control hot water and system seperately then without the zone valves ??? I need to read up on my notes again lol

 

[tamz]

If it is a gravity system the pump will usually be on the return but not always. It can be hard to trace the pipes as they may cross in the fireplace and if the pump is under the floor you may have to remove the pipebox too. Feeling them won't do much good after it has been swapped as you will have reverse circulation.

We have all done it :lol:

Just make sure you remember which way around it was or since most have a camera phone, maybe take a wee photy.

 

[tamz]

how did you control hot water and system seperately then without the zone valves ??? I need to read up on my notes again lol

The HW worked on gravity. The boiler lit and it went itself.
Turning on the heating just starts the pump too.
You can't have CH without HW unless a zone valve is fitted (C plan)

 

[GQuigley67]

makes sense now, i dont really think about these things when im on the job just where am i connecting my pipes lol

 

[tamz]

You'll learn. It just takes time and a few f ups and it sticks in your head.

 

[heliotrope]

makes sense now, i dont really think about these things when im on the job just where am i connecting my pipes lol

:heart: I don't even think where I am connecting when I am on the job, as long as I'm on the job :wink::wink:. I'll ask her name
in the morning.

 

[GQuigley67]

what you talking about willis ?