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Biodiesel => Biodiesel equipment => Topic started by: Carrington on November 25, 2012, 11:01:48 PM

Title: Heating pump on the flow or return
Post by: Carrington on November 25, 2012, 11:01:48 PM

Hi all
I'm just about to start plumbing in a large heat exchange that is feed from the boiler . Just wondering if its best to have the pump coming straight out the boiler or going back into it.
The heat exchange is 80m of scaffold tube (1 1/2 ish) and the feed is the same tube but due to pipe I have to hand the return will be 1 inch.
Any advice greatly recieved or I'll just go in blindly like normal.

Paul

Title: Re: Heating pump on the flow or return
Post by: Julian on November 26, 2012, 12:22:34 AM

Fitting it on the coolest park of the circuit will be kindest to the pump.

Title: Re: Heating pump on the flow or return
Post by: Carrington on November 26, 2012, 07:40:21 AM

Yes that what I was thinking and return the flow back in at the bottom of the boiler so that it draws from the top.

Title: Re: Heating pump on the flow or return
Post by: Rotary-Motion on November 26, 2012, 08:24:39 AM

i have read this but not sure where you are and what you are doing so cant answer, but i am interested, just thought it better to write this thatn nothing, may need a pixture diagram to get a jist of your needs,,,

Title: Re: Heating pump on the flow or return
Post by: Tony on November 26, 2012, 08:27:49 AM

On our domestic boiler the pump is on the hot side before the diverter valve.  No problems in over 5 years (well, not with the pump anyway!)

Title: Re: Heating pump on the flow or return
Post by: 1958steveflying on November 26, 2012, 10:05:57 AM

Quote from: Tony on November 26, 2012, 08:27:49 AM

On our domestic boiler the pump is on the hot side before the diverter valve.  No problems in over 5 years (well, not with the pump anyway!)

Our Worcester/Bosch boiler also has it's pump on the hot side, the previous boiler which did not have an internally fitted pump had it directly above the boiler in the ceiling cavity also on the hot side.

Title: Re: Heating pump on the flow or return
Post by: julianf on November 27, 2012, 10:27:13 AM

Im 99% certain that JIM.M on the other group always advocates them on the hot side.

I cant work out why though - i think it may be something to do with header tanks, but i still have not figured it out!

Title: Re: Heating pump on the flow or return
Post by: Soft top on November 28, 2012, 04:17:52 PM

The old fashioned way was to put the pump on the return. That was because the old pumps did not like the high temps that were produced by the solid fuel boilers. Nowdays pumps are nearly always put on the flow. A modern pump can quite easily deal with high temps. A disadvantage to having the pump on the return is that if the pump is running and you try to bleed air from the system it could suck air in and cause an air lock.

Title: Re: Heating pump on the flow or return
Post by: Carrington on November 28, 2012, 04:53:50 PM

Cool looks like its going on the flow then if I cn gett the pipe work sorted ,
All going fubar at mo