Piping my flow and return

[HawkWhiteFinger]

Hi there,

I'm running a new heating system in my house and I want advice on the end of my flow and return. Here's a drawing

So, should I link it to maintain flow and return? Link with a balancing valve? Or have the radiator linked and balanced within the flow and return?

What really matters and what are the pros and cons of each set up?

Thanks.

 

[dancinplumba]

link it: water wont go thru rads.
use auto bypass on other way

 

[HawkWhiteFinger]

I don't understand about auto bypass on other way?

 

[dancinplumba]

place an automatic bypass valve between flow and return, this will automatically adjust to resistances causd by trv's shutting also allows minimum flow thru boiler that boiler requires and stops pump straining

 

[dancinplumba]

you dont need to join flow and return at the end of each rad run,
you can put auto bypass a couple of metres after boiler, and after pump but before any valves, tho check boilers mi's

 

[ecowarm]

Just like the revised pic

 

[HawkWhiteFinger]

In the revised pic the last rad is through the end of the circuit, so is that rad balanced to allow the flow to continue?

 

[ecowarm]

How many rads are you installing? Its usual to install as per my pic and a by-pass if needed is fitted after the pump between F/R.

All rads are then balanced

 

[HawkWhiteFinger]

I have 7 in total. Was thinking of two zones, with three rads on one zone and four rads on another zone. So an auto bypass sounds good after the pump in that case, then the last radiator on the end of each zone can be plumbed through the circuit at the end.

 

[ecowarm]

Thermo rad valves on all rads execpt the one where the room stat is

 

[HawkWhiteFinger]

Thermo rad valves on all rads execpt the one where the room stat is

What goes on the rad where the stat is then? Lock sheilds each end? If so could I use that to balance the system instead of a bypass valve?

 

[ecowarm]

Some boilers require an auto by-pass valve as well, yes lock sheilds

 

[HawkWhiteFinger]

Its a Potterton Promax 30 HE, can't remember without looking but I don't think it needs an auto bypass.

 

[HawkWhiteFinger]

Actually, can I do it like this? With a balancing valve at the end of the circuit, rather than elsewhere, so that I've still got the option to shut off radiators when I like and there's still flow throughout the circuit?

 

[wheeto]

Actually, can I do it like this? With a balancing valve at the end of the circuit, rather than elsewhere, so that I've still got the option to shut off radiators when I like and there's still flow throughout the circuit?

Yes but it's silly - you want the bypass as close to the boiler as possible so that when the TRVs close, hot water doesn't have to flow all the way around the circuit! On the furthest radiator, you just fit an elbow to connect it to F & R rather than a Tee ... because there's nowhere else the water needs to go.

 

[ecowarm]

Why do you want flow through the circuit? if you have a room stat and 2 or 3port valve and the house is up to temp why have flow round the rads?

 

[dancinplumba]

Actually, can I do it like this? With a balancing valve at the end of the circuit, rather than elsewhere, so that I've still got the option to shut off radiators when I like and there's still flow throughout the circuit?

???????????????????????????
why would you ????????????
and wont turn off rads

 

[dancinplumba]

mi's say this boiler doesn't require a bypass

 

[desrob]

agree with dancing plum.you can pipe it up any way you like,you have asked for advice and you've recieved some good advice, my advice is to take note..!...i came across a situation were the boiler had an integral bypass,first off the flow and return was a towel rail two lock shields, then a home made by pass(15mm connection)between flow and return,there was no circulation around the system,the flow was fine but it would not cycle back round the return,the temp differance on flow and return was around 40 degrees,the only part of the systems that was any were near normal was betweem boiler and bypass(home made one),because of the way it was piped up the boiler was knocking on reaching temp and knocking off,i made one amendment and every thing worked fine...???????

 

[HawkWhiteFinger]

Thanks for all the repies. Has given me some good thought for completing the system.